Efficacy of Advanced Cleaning Approaches in 3D Mandibular Molar Models: A Laboratory Study

Efficacy of Advanced Cleaning Approaches in 3D Mandibular Molar Models: A Laboratory Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Efficacy of Advanced Cleaning Approaches in 3D Mandibular Molar Models: A Laboratory Study Alissa Tiscareño, P.S. Ortolani-Seltenerich, Ana Ramírez-Muñoz, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5355986/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose: This study aimed to evaluate the efficacy of cleaning in minimally shaped mesial and oval distal canals of 3D models of mandibular molars, focusing on positive pressure irrigation, wireless and conventional passive ultrasonic irrigation (PUI), and diode laser (DL) at 980 nm. Methods: Forty-four replicas of natural mandibular molars were divided into four groups of eleven 3D resin models with apical size 25/.04 mesial (n=22) and 35/.04 oval distal canals (n=11) to evaluate different irrigation methods. Each root canal was uniformly filled with an artificial hydrogel to simulate a biofilm mixture. Following this preparation, the specified irrigation techniques were applied to the respective groups. Quantitative evaluations of pre- and post-irrigation images were performed to assess the efficiency of tissue removal along the entire length of the canal and in the apical, middle, and coronal thirds. Results: The findings revealed no significant differences in the initial amount of tissue between the samples, indicating uniform filling. In the apical region of mesial canals, conventional PUI showed the highest cleaning efficiency (14.1% residual tissue), significantly outperforming the other methods (p<0.05). Cordless PUI and DL also surpassed positive pressure irrigation, leaving 30.4% and 29.3% residual tissue, respectively, compared to 42.2% with positive pressure. In the middle third, all methods tested performed better than needle irrigation (p<0.05), but there were no significant differences in the coronal third or over the full canal length. Distal oval canals showed no significant differences in cleaning effectiveness among methods. Conclusions: Although no single method was superior in full canal length, supplementary techniques such as PUI and DL offer potential benefits over conventional irrigation methods, particularly in the apical third of the canal. Clinical Relevance: Complementary approaches such as conventional PUI and diode laser at 980 nm showed superior cleaning efficiency, particularly in the apical third. These results suggest their integration could improve cleaning effectiveness in minimally instrumented mesial canals. Chemomechanical preparation passive ultrasonic irrigation diode laser cleaning effectiveness root canal Figures Figure 1 Figure 2 INTRODUCTION The primary goal of endodontic treatment is to eradicate infections from the root canal system to promote the healing of the periradicular tissue [1]. Central to this process is chemomechanical preparation, which combines mechanical instrumentation and chemical irrigation [2]. This combination is crucial for effectively removing bacterial biofilm, necrotic tissue, and debris from the root canal and is essential for the success of the endodontic procedure [1, 2]. However, the complex anatomy of the root canal system often poses a challenge to the effectiveness of the chemomechanical preparation [3]. Features such as canal curvatures, isthmuses, lateral canals, and apical ramifications may result in incomplete preparation by standard instruments, leaving areas of the canal wall untreated [2]. Studies have shown that in some cases, between 18–29% of the canal surface can remain unprepared [2, 3], thus serving as a reservoir for tissue and bacterial persistence. A recent study by Siqueira, Pérez, Marceliano-Alves, Provenzano, Silva, Pires, Vieira, Rôças and Alves [3] has corroborated these findings by evaluating the morphological conditions of canal surfaces that remain uninstrumented. Using a correlative approach combining micro-computed tomography (micro-CT) and microscopy, the study revealed that apart from the coronal part of canals with vital pulp, the majority of non-instrumented areas in both vital and necrotic teeth contained tissue remnants and/or bacteria. The survival of bacteria after extensive chemomechanical preparation remains a significant concern [2, 4]. Studies have shown that tissue and bacteria remain in regions not reached by the instruments or where irrigants like sodium hypochlorite (NaOCl) are less effective [2, 3, 5]. Clinical, bacteriologic studies found bacteria in approximately 30–60% of canals after chemomechanical preparation [6–8], posing a post-treatment apical periodontitis risk due to incomplete root canal system disinfection [9]. This problem is partly due to the limitations of conventional needle and syringe irrigation techniques, which may only reach some areas within complex anatomical structures such as isthmuses, particularly in mandibular molars [2, 3, 10]. An isthmus, a narrow connection between two root canals [11], occurs in 17 to 100% of mandibular molars [12, 13]. Cleaning and disinfecting the isthmus is challenging [5], and due to physical limitations, it is almost impossible for instruments to reach the isthmus and other remote areas of the canal system. Consequently, cleaning and disinfection of these areas depends mainly on the chemical effects of irrigants [5]. Another significant challenge that can hinder the effectiveness of endodontic treatment is dealing with oval root canals [10]. The presence of oval canals presents a formidable obstacle when it comes to thoroughly cleaning, shaping, and disinfecting the root canal system, mainly when rotary instruments are used for the preparation process [10, 14]. This challenge arises because rotary instruments typically create a round cross-sectional configuration, leaving recesses unprepared at the ends of the largest diameter of the oval canal [10]. Oval canals are common in certain types of teeth, such as mandibular incisors, maxillary second premolars, and the distal root of mandibular molars [15]. Studies using micro-CT scans have shown that the unprepared canal surface in oval canals could vary from 17–80%, depending on the instrumentation techniques used [10, 16]. To overcome these limitations, there has been an increasing focus on incorporating supplementary techniques to enhance disinfection [5, 6]. These include various forms of ultrasonic activation and lasers [5, 17], which have been shown to have the potential to improve irrigation performance and reach complex anatomical areas of the canal. Passive ultrasonic irrigation (PUI) has emerged as a significant advancement in endodontic irrigation [18]. This approach is recommended to activate and agitate the irrigating solution by generating acoustic streaming and cavitation. The advent of new cordless ultrasonic activation devices has further enhanced this aspect of endodontic therapy, providing clinicians with more user-friendly options. However, the efficacy of additional PUI treatment with NaOCl, as shown in in vitro and in vivo studies, showed inconclusive results [5, 6]. Diode lasers (DL), used in endodontics for tissue dissolution in root canal treatments, have also attracted considerable attention. DL, e.g., with a wavelength of 980nm, has shown promising results in activating root canal irrigants, enabling efficient tissue dissolution of the root canal system [17]. The DL operates by inducing a rapid temperature increase, triggering the irrigant and forming vaporized bubbles, which enhance soft tissue dissolution [17]. Numerous studies have investigated the disinfection capacity of DL at wavelengths of 655–810 nm in conjunction with a photosensitizer for photodynamic therapy to optimize intracanal disinfection [19, 20]. However, the cleaning effectiveness of DL at a wavelength of 980 nm compared to other methods such as PUI or conventional needle and syringe has not yet been investigated. An important trend in endodontics is the adoption of a minimally invasive treatment approach (MIT). MIT emphasizes the preservation of structural dentin and aims to increase fracture resistance and prolong the longevity of endodontically treated teeth [21]. It is worth noting that removing dentin from the root canal may lead to a redistribution of stress towards the apical region, which in turn may reduce the tooth's resistance to flexural forces and increase the risk of fracture [21]. Nevertheless, it is essential to recognize that this conservative preparation method is associated with limitations. This is mainly because many conventional irrigation techniques rely on larger preparations for optimal fluid dynamics and antibacterial effects [22, 23]. Therefore, there is a crucial need to develop irrigation techniques consistent with the principle of treating minimally prepared root canals. To maintain the mechanical efficiency of the MIT approach, it seems essential to carefully incorporate extended conservative access cavities and minimize the removal of root dentin during shaping while ensuring that the cleanliness of the root canal system remains uncompromised. This study evaluated the cleaning effectiveness of positive pressure irrigation (control), wireless and conventional PUI, and DL at a wavelength of 980 nm in minimally prepared root canals using mesial and oval distal canals of 3D resin replicas from mandibular molars of natural teeth. MATERIALS AND METHODS Sample Preparation This study did not require approval from an ethics committee, as it did not involve the use of human or animal teeth, tissues, or cells. The sample size was determined using G*Power 3.1 software (Heinrich Heine Universität, Duesseldorf, Germany). The significance level was set at 0.05, and the statistical power at 80%. Based on this analysis, at least eight 3D dental replicas per experimental group were required. Eleven 3D resin replicas of natural mandibular molars were obtained (Surpreendente 3D tooth, Vila Nova de Gaia, Porto, Portugal). These replicas were selected according to specific criteria: Mesial Vertucci Class II mandibular molars with moderately curved roots (< 20º), consistently with an isthmus between both roots in the apical region and oval distal canals, apical diameters not exceeding size #15 for mesial canals and #30 for distal canals, and lengths between 20 and 21 mm. For a canal to be classified as oval-shaped, it was requisite that the buccolingual diameter be at least twice the magnitude of the mesiodistal diameter. The mesial and distal canal replicas were instrumented using One RECI 25/.04 (Coltene Whaledent, Altstätten, Switzerland) for the former and 35/.04 for the latter at 300–400 rpm, 1.2 N, 170°/60° according to the manufacturer's recommendations and rinsed with 2 mL of distilled water during instrumentation using a 30 gauge (G) Navitip needle (Ultradent, South Jordan, UT, USA) positioned 3 mm from the working length (WL). After instrumentation, the replicas were scanned with micro-CT. This resulted in eleven different mandibular molar anatomies, enlarged to 25/.04 in the mesial canals and 35/.04 in the distal canals, which were subsequently printed. This procedure eliminated biases associated with the instrumentation for each anatomy. Micro-CT Scanning The 3D replicas were scanned after chemomechanical preparation using a Phoenix Vitomex S240 micro-CT scanner (General Electric, Boston, MA, United States). Scan parameters included an isotropic resolution of 20.0 mm, 105 kV, 70 mA, a full 360-degree rotation around the vertical axis, and a 0.1-mm-thick filter, resulting in a scan time of approximately 25 minutes per replica. These scans were reconstructed using Phoenix-x 3D software (General Electric, Boston, MA, United States). A total of 1250 images per replica were generated with settings such as ring artifact correction at 8, beam hardening correction at 50%, and smoothing set at 6. STL files were generated from these reconstructions using 3D Slicer 5.0.3 software ( http://www.slicer.org ) to support the internal visualization of the individual anatomical structures. Manufacture of 3D Replicas in Resin The STL files of the 3D replicas were imported into AnyCubic PhotonWorkshop software ( https://www.anycubic.es ) to determine the exact positioning and support required for the printing process. Eleven anatomically identical replicas were then placed in the reservoir of the Anycubic Photon Mono M5s printer (Anycubic Technology Co., Shenzhen, China), which has a resolution of up to 10 µm. The printing file, stored on a SanDisk USB flash drive (Milpitas, California, USA), was used in the printer, which was filled with 200 mL of transparent water-soluble resin (Anycubic Technology Co., Shenzhen, China) with a wavelength of 365–405 nanometers. The printing process took about 90 minutes. After printing, the replicas were cleaned in hot water using the Anycubic Wash & Cure Plus device (Anycubic Technology Co., Shenzhen, China) to remove excess resin and subjected to a 20-minute polymerization process for final curing. The distal root of each 3D replica was separated to avoid root overlap and noise in the final image analysis. For a comprehensive comparative analysis, each group included eleven 3D resin replicas with mesial (n = 22) and distal canals (n = 11). Tissue Simulation with Hydrogel Model A 30G NaviTip needle was used to evenly fill the canal system with an artificial biofilm mixture(AB) formulated with a hydrogel. The hydrogel, which was in a liquid state at the time of injection, had excellent capillary properties and provided uniform distribution with no voids throughout all canal areas. The hydrogel was prepared as described by Robinson, Macedo, Verhaagen, Versluis, Cooper, van der Sluis and Walmsley [24], dissolving 3 g of gelatin (Merck, Darmstadt, Germany) and 0.06g of hyaluronan (sodium hyaluronate 95%, Fisher, Waltham, MA, USA) in 45 mL of deionized water at 50°C. In addition, 0.25 g of red food dye (Condi Alimentar, Camarate, Portugal) and 0.1 g of hollow glass beads (Sigma Aldrich, Bornem, Belgium) were added to improve the visibility of AB. The hydrogel was kept at 30°C before injection and solidified within 1 minute at room temperature, a process that was checked for each sample to ensure consistency. Experimental Groups Forty-four 3D replicas were divided into four groups, each consisting of eleven anatomical models of mesial (n = 22) and oval distal canals (n = 11) that were activated as follows: Positive Pressure (Control) irrigation with an open-ended 30G needle positioned 3 mm up of the WL. Cordless PUI Ultra X (Eighteeth, Jiangsu, China), with two activation cycles of 30 seg using the silver tip size 20/.02 positioned 2 mm up of the WL. Conventional PUI (Varios 370 lux, NSK, USA) with two activation cycles of 30 seg using the Irrisafe 20/.02 tip (Acteon, Merignac, France) positioned 2 mm up of the WL. DL at 980nm with a power of 1W x 16 plus (Woodpecker Medical Instrument Co., LTD, Guangdong, China) and the 0.2 mm tip positioned 3 mm up the WL. Two activation cycles of 30 seconds were done during the procedure. After initial photographic documentation, the apical foramen was sealed with TopDam (FGM, Joinville, SC, Brazil) to simulate the vapor lock effect. The teeth were then mounted vertically on a holder designed for intracanal procedures. Each canal was rinsed with 2 mL of water in the mesial roots, followed by supplementary procedural steps. This process was repeated in each canal to reapply the adjunctive methods to improve tissue debridement. For the group using needle and syringe, irrigation was performed with 4 mL of water per canal, using continuous in-and-out movements with an amplitude of 3–4 mm. A total volume of 4 mL of water was used in each canal, but the apical third ultimately received 8 mL due to confluent anatomy. In contrast, in the distal canals, an initial volume of 4 mL of water was introduced, followed by the initiation of the first 30-second cycle. A further 4 mL was introduced into the canal to activate and agitate the solution. Continuous irrigation was performed in the group using the traditional needle and syringe technique, and 8 mL of irrigation fluid was administered. A single operator, an endodontics specialist, conducted the entire procedure. Tissue Cleaning Efficiency Before and after irrigation, each model underwent microscopic photography (Carl Zeiss, Berlin, Germany) using a special holder to ensure uniform positioning. The initial and final photographic images were opened in the Keynote program (Apple Inc.), and the same size and position were confirmed by superimposing the images. The anatomical structures, such as dentin, were eliminated from the images, leaving only the red-colored root canal system (hydrogel tissue model) in the initial and final samples. For the evaluation, consideration was given to the fact that both main canals had a single apical foramen and an isthmus zone in the apical region connecting both root canals. These modified images were integrated into ImageJ 1.50d software (National Institutes of Health, Bethesda, MD) to create binary images, facilitating quantification of tissue surface area (mm 2 ) across the entire canal and in the apical, middle, and coronal thirds and the percentage of remaining tissue for each needle group was calculated based on the differences between the pre-and post-irrigation images. Statistical Analysis Data distribution was assessed using the Shapiro-Wilk normality test and graphical analysis. Given the normal distribution of data, the Student's T-test for independent samples was employed for comparative analyses of the quantitative assessment of remaining tissue between groups. All statistical analyses were conducted using SPSS statistical software (Statistical Package for the Social Sciences 21.0; IBM Corp, Armonk, NY), with the significance level set at 5%. RESULTS Table 1 presents the data from the quantitative analysis of the remaining tissue, showing no significant differences (p > 0.05) in the initial amount of tissue between the 3D replicas, suggesting a uniform and comparable filling of the samples. Table 1 Residual tissue in mesial canals on the full canal length and the apical, middle, and coronal thirds; expressed as mean (median; range) Features (mean-median-range) Conventional seringe Wireless PUI Conventional PUI Laser 1W Tissue remants All canal Surface(mm 3 ) Initial surface 17453.2 (16862.4; 6997–26698) 17168.4 (15986.3; 5909–28076) 17568.1 (16536.3; 6408–27458) 17877.4 (16398.2; 6205–27809) Final 6800.2 (6375.2; 2012–16034) 5837.4 (5640.3; 0-13482) 6944.2 (6530.3; 0-14488) 6625.4 (6909.1; 0-16164) Δ % 36.1 (36.3; 11–62) 29.1 (23.2; 0–65) 37.3 (37.2; 0–55) 35.4 (37.4; 0–80) Apical Surface(mm 3 ) Initial 3749.3 (3692.4; 933–9456) 3567.3 (3479.3; 628–8413) 3460.2 (3707.4; 107–4763) 3549.1 (3208.2; 853–8514) Final 1574.3 (870.2; 69-8192) 1246.1 (889.4; 0-3923) 484.6 (398.2; 0-6052) 1035.3 (965.1; 0-4128) Δ % 42.2 (40.3; 7–87) 30.4 (25.2; 0–84) 14.1 (1.3; 0–87) 29.3 (22.2; 0–85) Middle Surface(mm 3 ) Initial 5708.8 (5679.1; 2301–9934) 5494.2 (5463.4; 2460–9527) 5413.4 (5254.3; 2614–9644) 5277.2 (5086.1; 2795–9547) Final 1951.3 (1566.2; 0-5603) 745.2 (500.4; 0-4726) 777.2 (694.3; 0-4875) 659.2 (654.3; 0-4769) Δ % 34.3 (31.1; 0–85) 13.4 (10.2; 0–53) 14.3 (12.2; 0–67) 12.1 (10.1; 0–57) Coronal Surface(mm 3 ) Inicial 8387.7 (8229.2; 3936–11567) 8470.4 (8342.1; 3857–11760) 8153.1 (8174.1; 3466–11834) 8595.4 (8063.2; 3305–11618) Final 2995.8 (2557.1; 0-8219) 2559.4 (2483.1; 0-7609) 2453.6 (2396.3; 0-8539) 2590.3 (2457.2; 0-7997) Δ % 35.1 (34.1; 0–84) 30.4 (29.1; 0–75) 30.2 (33.2; 0–81) 30.1 (34.2; 0–83) In the mesial canals, no significant differences in cleaning efficiency were found between the four groups in the full canal length (p > 0.05). About the apical region of the canal, conventional PUI showed significantly better cleaning performance in the mesial canals of mandibular molars compared to the other groups (p < 0.05). Specifically, the percentages of residual tissue were as follows: 42.2% for positive pressure irrigation with needle and syringe, 29.3% for DL, 30.4% for cordless PUI, and 14.1% for conventional PUI, as shown in Fig. 1 and detailed in Table 1 . Furthermore, wireless PUI and DL exhibited enhanced cleaning efficiency compared to conventional needle irrigation (p 0.05). In the evaluation of the middle third, the analysis revealed no significant differences between the activation techniques (p > 0.05). Nevertheless, all methods proved significantly more effective than conventional irrigation with needle and syringe (p 0.05). When analyzing the distal oval canals, the percentage of remaining tissue over the entire length of the canal was found to range from 47.2–37.4% for the needle irrigation and DL. Comparable percentages were observed for the conventional PUI and wireless PUI groups at 38.4% and 39.4%, respectively (see Table 2 ). In contrast, the irrigation efficiency in the apical region varied between 41.2% in the cordless PUI and 40.3% in the conventional PUI group. Meanwhile, the percentages for positive pressure irrigation and the DL method were reported as 42.3% and 35.2%, respectively (Fig. 2 ). Statistical analysis revealed no significant differences between the groups regarding cleaning effectiveness, neither across the full canal length nor in any third of the canal (p > 0.05). Table 2 Residual tissue in distal oval canals on the full canal length and the apical, middle, and coronal thirds; expressed as mean (median; range) Features (mean-median-range) Conventional seringe Wireless PUI Conventional PUI Laser 1W Tissue remants All canal Surface(mm 2 ) Initial surface 14166.2 (13983.3; 6695–22107) 14037.2 (13019.2; 6416–22449) 14587.3 (13761.2; 6353–22642) 14163.3 (13045.1; 6522–22445) Final 6670.1 (4787.1; 606-17830) 5486.3 (4719.2; 0-13341) 5570.3 (4676.1; 0-18473) 5285.2 (4841.2; 0-15702) Δ % 47.2 (41.2; 9–88) 39.4 (32.3; 0–85) 38.4 (26.3; 0–77) 37.4 (23.1; 0–91) Apical Surface(mm 2 ) Initial 2788.3 (2483.2; 695–5483) 2356.4 (2129.3; 678–5266) 2425.2 (2262.2; 674–5160) 2420.3 (2396.1; 658–5381) Final 1080.4 (945.3; 216–3131) 951.3 (835.4; 0-3375) 970.1 (801.3; 0-3732) 859.2 (730.2; 0-2549) Δ % 42.3 (41.2; 13–71) 41.2 (31.3; 0–86) 40.3 (37.2; 0–85) 35.2 (31.2; 0–83) Middle Surface(mm 2 ) Initial 5620.3 (4720.1; 1700–8417) 5397.2 (4587.5 (1807–8646) 5558.4 (4565.2; 1622–8599) 5424.1 (4583.4; 1738–8506) Final 1345.4 (1293.4; 0-5248) 1771.2 (1760.1; 0-5302) 1389.3 (103.2; 0-1168) 1387.4 (1223.1; 0-5919) Δ% 24.1 (21.2; 0–85) 32.3 (21.2; 0–86) 24.4 (22.1; 0–89) 23.3 (22.2; 0–88) Coronal Surface(mm 2 ) Inicial 7636.3 (7098.1; 4795–9894) 7480.2 (7297.3; 4550–9515) 7780.3 (7584.1; 4798–9400) 7713.3 (7576.3; 4355–9502) Final 3715.2 (3084.3; 0-9255) 3170.2 (2885.4; 0-8616) 3568.4 (3308.2; 0-8692) 3631.2 (3389.1; 0-8415) Δ% 49.1 (45.3; 0–94) 41.3 (38.2; 0–97) 45.3 (41.2; 0–96) 47.3 (43.2; 0–96) DISCUSSION The objective of this study was to evaluate the cleaning effectiveness of different agitation and activation techniques in root canals that have undergone conservative preparation. The analysis has primarily highlighted the limitations of using traditional needles and syringes for root canal irrigation. Although these conventional methods are commonly used, the present study shows their suboptimal cleaning efficiency when minimal instrumentation was performed in complex anatomies, especially in the apical third of the root canal. Conventional root canal irrigation with positive pressure is mainly limited by its inability to remove tissue thoroughly [3], particularly in complex root canal anatomies [2]. This study emphasizes this limitation, showing that conventional needle irrigation is significantly less efficient at tissue removal than alternative techniques. This discrepancy is especially evident in the apical region of the mesial canals of mandibular molars, where conventional needle irrigation leaves a significantly higher percentage of residual tissue (42.2%) compared to adjunctive approaches. The findings suggest that conventional needle irrigation remains a foundational technique during chemomechanical preparation. Still, it is essential to emphasize that it needs to be complemented by more advanced techniques such as PUI or DL, specifically when dealing with teeth featuring intricate anatomical features and minimal instrumentation [25]. However, It is important to point out that in the present study, the mesial canals were instrumented up to a size 25/.04. Instrumentation of the root canal to a larger size, such as #35, is crucial for several reasons when using a needle and syringe for irrigation [22, 26]. Firstly, enlarging the canal size facilitates greater fluid dynamics, allowing for increased flow and better access of the irrigant to the canal's entirety [22], including its apical region [26]. This is particularly important because the effectiveness of needle and syringe irrigation heavily relies on the physical flow of the irrigant to remove tissue debris and disinfect the canal [27]. Larger instrumentation sizes create a wider canal space, improving the penetrability and flow of the irrigant [23], thus enhancing the renewal and exchange of the solution within the canal system [28]. The mechanical limitation of a needle and syringe is primarily its inability in narrower canals to agitate the irrigant sufficiently within the complex root canal system and achieve optimal flow [29], especially in the apical third, reducing its efficacy in tissue removal and disinfection [23]. The study's results indicate that conventional PUI outperformed other methods in the mesial canals of mandibular molars, with significantly less residual tissue (14.1% for conventional PUI compared to 42.2% for needle and syringe, 29.3% for DL, and 30.4% for cordless PUI), highlight the effectiveness of PUI in challenging areas. The results of this study agree with another where greater cleaning was observed when ultrasonic activation was used in canals with smaller apical preparations compared to using only a conventional syringe [25]. Surprisingly, traditional PUI performed significantly better than wireless PUI in the apical region of the root canal. Although both methods are based on similar principles, the results of this study suggest that conventional PUI has greater activation and agitation capabilities than wireless PUI. Future studies should validate these findings, evaluating the wavelengths and powers of both methods. The similar performance of wireless PUI and DL, both showing enhanced efficiency over needle irrigation, underscores the importance of selecting advanced irrigation methods to optimize root canal cleaning. PUI, by generating acoustic streaming and cavitation effects [18], and DL, by activating irrigants and inducing tissue dissolution through rapid temperature increases and the formation of vaporized bubbles, [17] may improve the cleaning efficacy. These advanced techniques facilitate deeper penetration of irrigants into difficult-to-reach areas, significantly improving cleaning efficacy in the root canal system [17, 25]. In the middle third of the root canals, all activation techniques proved significantly more effective than conventional irrigation with a needle and syringe, underlining the latter's inefficiency in removing tissue, probably because of the narrower space that limits their action. However, no significant differences were found among the activation methods in this region. This indicates that while activation methods are advantageous, the choice between them may not significantly impact cleaning outcomes in the middle third of the root canals. In the coronal third, the study did not reveal significant differences in cleaning ability among the various groups. This suggests that conventional needle irrigation may be comparably effective in this region to activation methods, and the choice of technique may be less critical. However, caution is required when interpreting the current study's findings. First, no comparison was made between smaller and larger apical diameters to determine whether activation and agitation techniques could replace apical enlargement in the mesial roots of mandibular molars or whether they should merely serve as supplementary methods to improve tissue removal and disinfection efficacy. Second, the main goal in managing apical periodontitis is the eradication of bacterial biofilm in the root canal system [1]. However, increasing emphasis is being placed on minimally invasive endodontic treatments, which, while increasing fracture resistance [30], could potentially compromise disinfection [31] and, consequently, treatment outcomes. A Previous study showed that when root canals are prepared to an apical size of 20 or 25, NaOCl cannot effectively reach the working length when using syringes and needles [29]. To address this problem, in vitro studies have developed activation and agitation irrigation strategies to ensure thorough disinfection of minimally prepared canals [25, 32]. To date, no clinical studies provide evidence of conducting minimal root canal preparations and relying on agitation and activation techniques to compensate for disinfection. Existing evidence suggests that larger apical diameters allow better renewal of the irrigant in the apical third of the root canal [23], resulting in enhanced disinfection [33] and, consequently, a higher success rate in endodontic treatment [34]. Future clinical investigations must validate the efficacy of minimally shaped canals in complex anatomies such as mandibular molars using adjunctive approaches, particularly regarding their disinfection ability compared to larger apical diameters. These findings could serve as a surrogate endpoint for the overall success of endodontic treatment. In this study, an important aspect was comparing eleven different anatomical variations of natural mandibular molar teeth. These molars were divided into four groups, resulting in forty-four 3D resin replicas. This meticulous approach helped us minimize any potential biases arising from anatomical differences, and it is more representative of studies on extracted natural teeth where different anatomies are utilized, as opposed to using a single anatomy repeatedly to compare different methods. Furthermore, an interesting finding was the consistency in the amount of initial tissue in the samples. Our preliminary analysis revealed no significant differences in the presence of tissue when comparing the different groups. It is also worth noting that the mandibular molars we selected with Class II Vertucci anatomy in the mesial canals and oval-shaped in the distal canals provided a representative challenge for evaluating agitation and activation techniques. Oval canals present unique challenges due to their shape, which often leaves recesses not adequately reached by rotary instruments [10], resulting in incomplete debridement and inadequate disinfection [35]. This is compounded by the difficulty of achieving thorough irrigation [10], which is crucial for removing tissue remnants and bacterial biofilms from these complex anatomical structures [10, 25]. The results of the present study showed that in the distal oval canals, the percentage of tissue remaining along the entire length of the canal ranged from 47.2–37.4% for the needle irrigation and DL groups. Comparable percentages were observed for the conventional PUI and wireless PUI groups at 38.4% and 39.4%, respectively, and no significant differences were observed in any third of the canal between the groups evaluated. These findings suggest that none of the techniques studied achieved greater tissue cleaning in oval canals than conventional syringes. The results of this study highlight the inherent limitations resulting from the canal's oval shape, which can hinder the cleaning effectiveness of even the most sophisticated irrigation methods. These findings are consistent with previous studies that found no significant differences when using different activation and agitation techniques in oval canals [14, 36]. These results are critical for several reasons. First, they suggest that while supplementary techniques can play a role in endodontic treatment, their ability to significantly outperform traditional irrigation methods in oval canals is limited [14]. This limitation is particularly pronounced given the shape of these canals, which inherently complicates the task of comprehensive tissue removal [10]. Secondly, the percentages of remaining tissue suggest that a substantial amount of the canal surface remains uncleaned, regardless of the irrigation technique used [14]. This scenario could compromise the disinfection process, leaving the canal system susceptible to persistent infection and endodontic treatment failure [37]. It is crucial to emphasize that regardless of the specific technique employed or the type of anatomical variation considered, none of the procedures completely removed the tissue, particularly in the apical third of the canal. The apical root canal area is crucial in infection control, as bacteria in this region can contribute to post-treatment apical periodontitis [38]. However, the complete tissue removal from this area remains challenging with current techniques. Our findings are consistent with previous studies that have also reported a higher incidence of residual tissue and/or bacteria in the apical region of mesial and distal canals of mandibular molars [2, 3, 10]. In addition, tissue persistence may interfere with the proper filling of the root canal, which may lead to treatment failure in necrotic teeth [39]. As demonstrated in this study, the main reason for tissue persistence is the limitation of existing techniques in the reliable delivery of irrigants to different regions of the root canal, particularly those with complex anatomical features. These findings emphasize the urgent need for innovative methods that can predictably optimize tissue removal throughout the entire root canal system. Although an innovative approach was taken in this study, in which various natural tooth anatomies were 3D printed, it is essential to recognize its limitations. First, water served as an irrigant throughout the experiment, which means that the evaluation primarily focused on evaluating the mechanical aspects of the techniques and did not consider the chemical properties or capabilities of the irrigant. F Furthermore, utilizing resin replicas instead of natural teeth might lead to variations in irrigant diffusion and tissue removal. In the resin model, there is no buffering activity of the dentin, which happens in the natural teeth when sodium hypochlorite is used. Hence, the results obtained in this study by using distilled water may be overestimated. Finally, this is an in vitro study, so caution should be exercised when extrapolating these findings to real clinical scenarios. In conclusion, conventional PUI performed better than other methods in cleaning the mesial canals of mandibular molars, especially in the apical region. Cordless PUI and DL proved to be promising alternatives that offered better cleaning compared to conventional needle irrigation. All methods proved to be superior to conventional irrigation in the middle third of the canal. However, no significant differences were found between the tested groups in the distal oval canals, suggesting that the choice of irrigation technique may have less impact on cleaning efficiency in these canals. Declarations Alissa Tiscareño : Investigation, Methodology, Software. P.S. Ortolani-Seltenerich: Investigation, Supervision. Ana Ramírez-Muñoz : Data curation. Omar Pérez-Ron : Reviewing and Editing. Pedro M. Mendez S : Software, Data curation. Carmen Leal-Moya : Conceptualization, Supervision. Gaya C. S. Vieira : Conceptualization, Reviewing and Editing. Alejandro R. Pérez : Writing- Reviewing and Editing, Conceptualization, Supervision. Ethics Approval and Consent to Participate: As no human or animal teeth, tissues, or cells were used, it was not necessary to obtain an ethics committee to conduct the current study. Funding: No funding was obtained for this study. Conflict of Interest: The authors deny any conflicts of interest. Author Contribution A.T: Investigation, Methodology, Software. P.S.O.S: Investigation, Supervision. A.R-M: Data curation. O.P-R: Reviewing and Editing. P.M. M.S: Software, Data curation. C.L-M: Conceptualization, Supervision. G.C. S.V: Conceptualization, Reviewing and Editing. A.R.P: Writing- Reviewing and Editing, Conceptualization, Supervision. Data Availability The data are available upon reasonable request from the authors References Zandi H, Petronijevic N, Mdala I, Kristoffersen AK, Enersen M, Rôças IN, Siqueira JF Jr., Ørstavik D (2019) Outcome of Endodontic Retreatment Using 2 Root Canal Irrigants and Influence of Infection on Healing as Determined by a Molecular Method: A Randomized Clinical Trial. J Endod. 10.1016/j.joen.2019.05.021 Pérez AR, Ricucci D, Vieira GCS, Provenzano JC, Alves FRF, Marceliano-Alves MF, Rôças IN, Siqueira JF Jr. (2020) Cleaning, Shaping, and Disinfecting Abilities of 2 Instrument Systems as Evaluated by a Correlative Micro-computed Tomographic and Histobacteriologic Approach. J Endod 46:846–857. 10.1016/j.joen.2020.03.017 Siqueira JF Jr., Pérez AR, Marceliano-Alves MF, Provenzano JC, Silva SG, Pires FR, Vieira GCS, Rôças (2018) IN and Alves FRF What happens to unprepared root canal walls: a correlative analysis using micro-computed tomography and histology/scanning electron microscopy. Int Endod J 51:501–508. 10.1111/iej.12753 Siqueira JF Jr., Rôças IN, Marceliano-Alves MF, Perez AR, Ricucci D (2018) Unprepared root canal surface areas: causes, clinical implications, and therapeutic strategies. Braz Oral Res 32(suppl 1):e65. 10.1590/1807-3107bor-2018.vol32.0065 Alves FR, Andrade-Junior CV, Marceliano-Alves MF, Perez AR, Rocas IN, Versiani MA, Sousa-Neto MD, Provenzano JC, Siqueira JF Jr. (2016) Adjunctive Steps for Disinfection of the Mandibular Molar Root Canal System: A Correlative Bacteriologic, Micro-Computed Tomography, and Cryopulverization Approach. J Endod 42:1667–1672. 10.1016/j.joen.2016.08.003 Paiva SSM, Siqueira JE, Rocas IN, Carmo FL, Ferreira DC, Curvelo JAR, Soares RMA, Rosado AS (2012) Supplementing the Antimicrobial Effects of Chemomechanical Debridement with Either Passive Ultrasonic Irrigation or a Final Rinse with Chlorhexidine: A Clinical Study. J Endod 38:1202–1206. 10.1016/j.joen.2012.06.023 Vianna ME, Horz HP, Gomes BP, Conrads G (2006) In vivo evaluation of microbial reduction after chemo-mechanical preparation of human root canals containing necrotic pulp tissue. Int Endod J 39:484–492. 10.1111/j.1365-2591.2006.01121.x Neves MA, Provenzano JC, Rôças IN, Siqueira JF Jr. (2016) Clinical antibacterial effectiveness of root canal preparation with reciprocating single-instrument or continuously rotating multi-instrument systems. J Endod 42:25–29. 10.1016/j.joen.2015.09.019 Sjögren U, Figdor D, Persson S, Sundqvist G (1997) Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 30:297–306 Lacerda M, Marceliano-Alves MF, Pérez AR, Provenzano JC, Neves MAS, Pires FR, Gonçalves LS, Rôças (2017) IN and Siqueira JF, Jr. Cleaning and shaping oval canals with 3 instrumentation systems: a correlative micro-computed tomographic and histologic study. J Endod 43:1878–1884. 10.1016/j.joen.2017.06.032 Weller RN, Niemczyk SP, Kim S (1995) Incidence and position of the canal isthmus. Part 1. Mesiobuccal root of the maxillary first molar. J Endod 21:380–383 Mannocci F, Peru M, Sherriff M, Cook R, Pitt Ford TR (2005) The isthmuses of the mesial root of mandibular molars: a micro-computed tomographic study. Int Endod J 38:558–563. 10.1111/j.1365-2591.2005.00994.x Harris SP, Bowles WR, Fok A, McClanahan SB (2013) An anatomic investigation of the mandibular first molar using micro-computed tomography. J Endod 39:1374–1378. 10.1016/j.joen.2013.06.034 Alves FR, Almeida BM, Neves MA, Moreno JO, Rocas IN, Siqueira JF Jr. (2011) Disinfecting oval-shaped root canals: effectiveness of different supplementary approaches. J Endod 37:496–501. 10.1016/j.joen.2010.12.008 Wu MK, R'Oris A, Barkis D, Wesselink PR (2000) Prevalence and extent of long oval canals in the apical third. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 89:739–743 Paqué F, Balmer M, Attin T, Peters OA (2010) Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. J Endod 36:703–707. 10.1016/j.joen.2009.12.020 Hongo T, Watanabe S, Yao K, Satake K, Okiji T (2019) Evaluation of cleaning efficacy-related properties of root canal irrigant activation using a computer-controlled hot tip powered with a diode laser. Asian Pac J Dentistry 19:9–15. 10.47416/apjod.19-0256 van der Sluis LW, Versluis M, Wu MK, Wesselink PR (2007) Passive ultrasonic irrigation of the root canal: a review of the literature. Int Endod J 40:415–426. 10.1111/j.1365-2591.2007.01243.x Vendramini Y, Salles A, Portella FF, Brew MC, Steier L, de Figueiredo JAP, Bavaresco CS (2020) Antimicrobial effect of photodynamic therapy on intracanal biofilm: A systematic review of in vitro studies. Photodiagn Photodyn Ther 32:102025. https://doi.org/10.1016/j.pdpdt.2020.102025 Shrestha A, Kishen A (2014) Antibiofilm efficacy of photosensitizer-functionalized bioactive nanoparticles on multispecies biofilm. J Endod 40:1604–1610. 10.1016/j.joen.2014.03.009 Kishen A, Asundi A (2002) Photomechanical investigations on post endodontically rehabilitated teeth. J Biomed Opt 7:262–270. 10.1117/1.1463046 Boutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, Van der Sluis LW (2010) The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model. Int Endod J 43:874–881. 10.1111/j.1365-2591.2010.01761.x Rodrigues RCV, Zandi H, Kristoffersen AK, Enersen M, Mdala I, Ørstavik D, Rôças (2017) IN and Siqueira JF, Jr. Influence of the apical preparation size and the irrigant type on bacterial reduction in root canal-treated teeth with apical periodontitis. J Endod 43:1058–1063. 10.1016/j.joen.2017.02.004 Robinson JP, Macedo RG, Verhaagen B, Versluis M, Cooper PR, van der Sluis LWM, Walmsley AD (2018) Cleaning lateral morphological features of the root canal: the role of streaming and cavitation. Int Endod J 51 Suppl 1e55–e64. 10.1111/iej.12804 Lee OYS, Khan K, Li KY, Shetty H, Abiad RS, Cheung GSP, Neelakantan P (2019) Influence of apical preparation size and irrigation technique on root canal debridement: a histological analysis of round and oval root canals. Int Endod J 52:1366–1376. 10.1111/iej.13127 Boutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, Van der Sluis LW (2010) The effect of root canal taper on the irrigant flow: evaluation using an unsteady Computational Fluid Dynamics model. Int Endod J 43:909–916. 10.1111/j.1365-2591.2010.01767.x Boutsioukis C, Lambrianidis T, Verhaagen B, Versluis M, Kastrinakis E, Wesselink PR, van der Sluis LW (2010) The effect of needle-insertion depth on the irrigant flow in the root canal: evaluation using an unsteady computational fluid dynamics model. J Endod 36:1664–1668. 10.1016/j.joen.2010.06.023 Siqueira JF Jr., Araujo MC, Garcia PF, Fraga RC, Dantas CJ (1997) Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J Endod 23:499–502. 10.1016/S0099-2399(97)80309-3 Boutsioukis C, Gutierrez Nova P (2021) Syringe Irrigation in Minimally Shaped Root Canals Using 3 Endodontic Needles: A Computational Fluid Dynamics Study. J Endod 47:1487–1495. 10.1016/j.joen.2021.06.001 Plotino G, Grande NM, Isufi A, Ioppolo P, Pedullà E, Bedini R, Gambarini G, Testarelli L (2017) Fracture Strength of Endodontically Treated Teeth with Different Access Cavity Designs. J Endod 43:995–1000. 10.1016/j.joen.2017.01.022 Vieira GCS, Pérez AR, Alves FRF, Provenzano JC, Mdala I, Siqueira JF Jr., Rôças (2020) IN Impact of Contracted Endodontic Cavities on Root Canal Disinfection and Shaping. J Endod 46:655–661. 10.1016/j.joen.2020.02.002 Teed C, Hussein H, Kishen A (2023) Synchronized Microbubble Photodynamic Activation to Disinfect Minimally Prepared Root Canals. J Endod 49:198–204. 10.1016/j.joen.2022.12.003 Card SJ, Sigurdsson A, Ørstavik D, Trope M (2002) The effectiveness of increased apical enlargement in reducing intracanal bacteria. J Endod 28:779–783. 10.1097/00004770-200211000-00008 Fatima S, Kumar A, Andrabi S, Mishra SK, Tewari RK (2021) Effect of Apical Third Enlargement to Different Preparation Sizes and Tapers on Postoperative Pain and Outcome of Primary Endodontic Treatment: A Prospective Randomized Clinical Trial. J Endod 47:1345–1351. 10.1016/j.joen.2021.05.010 Siqueira JF Jr., Alves FR, Almeida BM, de Oliveira JC, Rocas IN (2010) Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. J Endod 36:1860–1865. 10.1016/j.joen.2010.08.001 De-Deus G, Belladonna FG, de Siqueira Zuolo A, Perez R, Carvalho MS, Souza EM, Lopes RT, Silva E (2019) Micro-CT comparison of XP-endo Finisher and passive ultrasonic irrigation as final irrigation protocols on the removal of accumulated hard-tissue debris from oval shaped-canals. Clin Oral Investig 23:3087–3093. 10.1007/s00784-018-2729-y Arnold M, Ricucci D, Siqueira JF Jr. (2013) Infection in a complex network of apical ramifications as the cause of persistent apical periodontitis: a case report. J Endod 39:1179–1184. 10.1016/j.joen.2013.04.036 Ricucci D, Siqueira JF Jr., Bate AL, Pitt Ford TR (2009) Histologic investigation of root canal-treated teeth with apical periodontitis: a retrospective study from twenty-four patients. J Endod 35:493–502. 10.1016/j.joen.2008.12.014 Siqueira JF Jr., Antunes HS, Pérez AR, Alves FRF, Mdala I, Silva E, Belladonna FG, Rôças (2020) IN The Apical Root Canal System of Teeth with Posttreatment Apical Periodontitis: Correlating Microbiologic, Tomographic, and Histopathologic Findings. J Endod 46:1195–1203. 10.1016/j.joen.2020.05.020 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5355986","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":376900468,"identity":"29c3ad48-b5fd-4417-9635-126f3386fefa","order_by":0,"name":"Alissa Tiscareño","email":"","orcid":"","institution":"University of Guadalajara","correspondingAuthor":false,"prefix":"","firstName":"Alissa","middleName":"","lastName":"Tiscareño","suffix":""},{"id":376900469,"identity":"956e1ae0-6efc-46f9-b6c6-7ae91ef936e7","order_by":1,"name":"P.S. Ortolani-Seltenerich","email":"","orcid":"","institution":"Universidad Católica San Antonio de Murcia","correspondingAuthor":false,"prefix":"","firstName":"P.S.","middleName":"","lastName":"Ortolani-Seltenerich","suffix":""},{"id":376900470,"identity":"25a352c8-d338-4b0d-a20b-39d1d5953f9f","order_by":2,"name":"Ana Ramírez-Muñoz","email":"","orcid":"","institution":"King Juan Carlos University","correspondingAuthor":false,"prefix":"","firstName":"Ana","middleName":"","lastName":"Ramírez-Muñoz","suffix":""},{"id":376900471,"identity":"39209c4d-bf5d-4d46-bd20-bbe682fa88b4","order_by":3,"name":"Omar Pérez-Ron","email":"","orcid":"","institution":"Surpreendente Group","correspondingAuthor":false,"prefix":"","firstName":"Omar","middleName":"","lastName":"Pérez-Ron","suffix":""},{"id":376900472,"identity":"0c347fdc-d916-4c0a-ad46-3c7f1927c1db","order_by":4,"name":"Pedro M. Mendez S","email":"","orcid":"","institution":"Surpreendente Group","correspondingAuthor":false,"prefix":"","firstName":"Pedro","middleName":"M. Mendez","lastName":"S","suffix":""},{"id":376900473,"identity":"3745d245-8fad-4ed4-8479-24b2a3eae435","order_by":5,"name":"Carmen Leal-Moya","email":"","orcid":"","institution":"University of Guadalajara","correspondingAuthor":false,"prefix":"","firstName":"Carmen","middleName":"","lastName":"Leal-Moya","suffix":""},{"id":376900474,"identity":"68867d39-a6d3-4fad-8231-8b0802888007","order_by":6,"name":"Gaya C.S. Vieira","email":"","orcid":"","institution":"Private Practice","correspondingAuthor":false,"prefix":"","firstName":"Gaya","middleName":"C.S.","lastName":"Vieira","suffix":""},{"id":376900475,"identity":"fd7cfeb2-3067-4c96-89d4-4bf114d9bffb","order_by":7,"name":"Alejandro R. Pérez","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYDACdijNDyISCojRwgylJRtAWgxI0WJwAEwSoYO/mfnYg497bPKMz69O/PDAgEGeX+wAfi0Sh9nSDWc8Sys2u/F2swTQYYYzZycQsOYwj5k0z4HDidtunN0A0pJgcJuAFvnD/N/AWjbPOLv5B1FaDA7zsIG1bODv3UacLYaH2cwNZxxIS5xxg3ebRYKBBGG/yB1vfvbgwwGbxP7+s5tv/qiwkeeXJqAFCNgglARYpQRB5Uha+A8QpXoUjIJRMApGIAAAB2xE84a0KmgAAAAASUVORK5CYII=","orcid":"","institution":"King Juan Carlos University","correspondingAuthor":true,"prefix":"","firstName":"Alejandro","middleName":"R.","lastName":"Pérez","suffix":""}],"badges":[],"createdAt":"2024-10-29 16:38:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5355986/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5355986/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":69462204,"identity":"e8217c0a-3895-4859-8087-f93f487323a9","added_by":"auto","created_at":"2024-11-20 15:01:22","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1632112,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative images of mesial root canals instrumented to size 25/.04 and with the presence of hydrogel model before (A, C, E, G) and remaining tissue in the apical third (expressed in percentage) after (B) using Positive Pressure (42.2%). (D) Cordless PUI (30.4%). (F) Conventional PUI (14.1%), and (H) Diode Laser (29.3%).\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-5355986/v1/15c38367b29318a569adcd73.png"},{"id":69462206,"identity":"a55a3ba9-359a-4526-a3d9-a7edbd3804c6","added_by":"auto","created_at":"2024-11-20 15:01:22","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1383765,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrative visuals of remaining tissue in the apical region (expressed in percentage) with the different adjunctive approaches in oval distal canals. Images were taken before (A, C, E, G) and after irrigation with (B) Positive Pressure (42.3%). (D) Cordless PUI (41.2%). (F) Conventional PUI (40.3%), and (H) Diode Laser (35.2%).\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-5355986/v1/e8db4ebca3e9958fb02703c9.png"},{"id":79414491,"identity":"692f8a93-b934-49f4-8675-a414228b0f88","added_by":"auto","created_at":"2025-03-28 07:01:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4675981,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5355986/v1/4fa7aba2-d967-4958-b96c-a899a86548f2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Efficacy of Advanced Cleaning Approaches in 3D Mandibular Molar Models: A Laboratory Study","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe primary goal of endodontic treatment is to eradicate infections from the root canal system to promote the healing of the periradicular tissue [1]. Central to this process is chemomechanical preparation, which combines mechanical instrumentation and chemical irrigation [2]. This combination is crucial for effectively removing bacterial biofilm, necrotic tissue, and debris from the root canal and is essential for the success of the endodontic procedure [1, 2].\u003c/p\u003e \u003cp\u003eHowever, the complex anatomy of the root canal system often poses a challenge to the effectiveness of the chemomechanical preparation [3]. Features such as canal curvatures, isthmuses, lateral canals, and apical ramifications may result in incomplete preparation by standard instruments, leaving areas of the canal wall untreated [2]. Studies have shown that in some cases, between 18\u0026ndash;29% of the canal surface can remain unprepared [2, 3], thus serving as a reservoir for tissue and bacterial persistence.\u003c/p\u003e \u003cp\u003eA recent study by Siqueira, P\u0026eacute;rez, Marceliano-Alves, Provenzano, Silva, Pires, Vieira, R\u0026ocirc;\u0026ccedil;as and Alves [3] has corroborated these findings by evaluating the morphological conditions of canal surfaces that remain uninstrumented. Using a correlative approach combining micro-computed tomography (micro-CT) and microscopy, the study revealed that apart from the coronal part of canals with vital pulp, the majority of non-instrumented areas in both vital and necrotic teeth contained tissue remnants and/or bacteria.\u003c/p\u003e \u003cp\u003eThe survival of bacteria after extensive chemomechanical preparation remains a significant concern [2, 4]. Studies have shown that tissue and bacteria remain in regions not reached by the instruments or where irrigants like sodium hypochlorite (NaOCl) are less effective [2, 3, 5]. Clinical, bacteriologic studies found bacteria in approximately 30\u0026ndash;60% of canals after chemomechanical preparation [6\u0026ndash;8], posing a post-treatment apical periodontitis risk due to incomplete root canal system disinfection [9].\u003c/p\u003e \u003cp\u003eThis problem is partly due to the limitations of conventional needle and syringe irrigation techniques, which may only reach some areas within complex anatomical structures such as isthmuses, particularly in mandibular molars [2, 3, 10]. An isthmus, a narrow connection between two root canals [11], occurs in 17 to 100% of mandibular molars [12, 13]. Cleaning and disinfecting the isthmus is challenging [5], and due to physical limitations, it is almost impossible for instruments to reach the isthmus and other remote areas of the canal system. Consequently, cleaning and disinfection of these areas depends mainly on the chemical effects of irrigants [5].\u003c/p\u003e \u003cp\u003eAnother significant challenge that can hinder the effectiveness of endodontic treatment is dealing with oval root canals [10]. The presence of oval canals presents a formidable obstacle when it comes to thoroughly cleaning, shaping, and disinfecting the root canal system, mainly when rotary instruments are used for the preparation process [10, 14]. This challenge arises because rotary instruments typically create a round cross-sectional configuration, leaving recesses unprepared at the ends of the largest diameter of the oval canal [10]. Oval canals are common in certain types of teeth, such as mandibular incisors, maxillary second premolars, and the distal root of mandibular molars [15]. Studies using micro-CT scans have shown that the unprepared canal surface in oval canals could vary from 17\u0026ndash;80%, depending on the instrumentation techniques used [10, 16].\u003c/p\u003e \u003cp\u003eTo overcome these limitations, there has been an increasing focus on incorporating supplementary techniques to enhance disinfection [5, 6]. These include various forms of ultrasonic activation and lasers [5, 17], which have been shown to have the potential to improve irrigation performance and reach complex anatomical areas of the canal.\u003c/p\u003e \u003cp\u003ePassive ultrasonic irrigation (PUI) has emerged as a significant advancement in endodontic irrigation [18]. This approach is recommended to activate and agitate the irrigating solution by generating acoustic streaming and cavitation. The advent of new cordless ultrasonic activation devices has further enhanced this aspect of endodontic therapy, providing clinicians with more user-friendly options. However, the efficacy of additional PUI treatment with NaOCl, as shown in in vitro and in vivo studies, showed inconclusive results [5, 6].\u003c/p\u003e \u003cp\u003eDiode lasers (DL), used in endodontics for tissue dissolution in root canal treatments, have also attracted considerable attention. DL, e.g., with a wavelength of 980nm, has shown promising results in activating root canal irrigants, enabling efficient tissue dissolution of the root canal system [17]. The DL operates by inducing a rapid temperature increase, triggering the irrigant and forming vaporized bubbles, which enhance soft tissue dissolution [17].\u003c/p\u003e \u003cp\u003eNumerous studies have investigated the disinfection capacity of DL at wavelengths of 655\u0026ndash;810 nm in conjunction with a photosensitizer for photodynamic therapy to optimize intracanal disinfection [19, 20]. However, the cleaning effectiveness of DL at a wavelength of 980 nm compared to other methods such as PUI or conventional needle and syringe has not yet been investigated.\u003c/p\u003e \u003cp\u003eAn important trend in endodontics is the adoption of a minimally invasive treatment approach (MIT). MIT emphasizes the preservation of structural dentin and aims to increase fracture resistance and prolong the longevity of endodontically treated teeth [21]. It is worth noting that removing dentin from the root canal may lead to a redistribution of stress towards the apical region, which in turn may reduce the tooth's resistance to flexural forces and increase the risk of fracture [21]. Nevertheless, it is essential to recognize that this conservative preparation method is associated with limitations. This is mainly because many conventional irrigation techniques rely on larger preparations for optimal fluid dynamics and antibacterial effects [22, 23].\u003c/p\u003e \u003cp\u003eTherefore, there is a crucial need to develop irrigation techniques consistent with the principle of treating minimally prepared root canals. To maintain the mechanical efficiency of the MIT approach, it seems essential to carefully incorporate extended conservative access cavities and minimize the removal of root dentin during shaping while ensuring that the cleanliness of the root canal system remains uncompromised.\u003c/p\u003e \u003cp\u003eThis study evaluated the cleaning effectiveness of positive pressure irrigation (control), wireless and conventional PUI, and DL at a wavelength of 980 nm in minimally prepared root canals using mesial and oval distal canals of 3D resin replicas from mandibular molars of natural teeth.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSample Preparation\u003c/h2\u003e \u003cp\u003eThis study did not require approval from an ethics committee, as it did not involve the use of human or animal teeth, tissues, or cells. The sample size was determined using G*Power 3.1 software (Heinrich Heine Universit\u0026auml;t, Duesseldorf, Germany). The significance level was set at 0.05, and the statistical power at 80%. Based on this analysis, at least eight 3D dental replicas per experimental group were required.\u003c/p\u003e \u003cp\u003eEleven 3D resin replicas of natural mandibular molars were obtained (Surpreendente 3D tooth, Vila Nova de Gaia, Porto, Portugal). These replicas were selected according to specific criteria: Mesial Vertucci Class II mandibular molars with moderately curved roots (\u0026lt;\u0026thinsp;20\u0026ordm;), consistently with an isthmus between both roots in the apical region and oval distal canals, apical diameters not exceeding size #15 for mesial canals and #30 for distal canals, and lengths between 20 and 21 mm. For a canal to be classified as oval-shaped, it was requisite that the buccolingual diameter be at least twice the magnitude of the mesiodistal diameter.\u003c/p\u003e \u003cp\u003eThe mesial and distal canal replicas were instrumented using One RECI 25/.04 (Coltene Whaledent, Altst\u0026auml;tten, Switzerland) for the former and 35/.04 for the latter at 300\u0026ndash;400 rpm, 1.2 N, 170\u0026deg;/60\u0026deg; according to the manufacturer's recommendations and rinsed with 2 mL of distilled water during instrumentation using a 30 gauge (G) Navitip needle (Ultradent, South Jordan, UT, USA) positioned 3 mm from the working length (WL).\u003c/p\u003e \u003cp\u003eAfter instrumentation, the replicas were scanned with micro-CT. This resulted in eleven different mandibular molar anatomies, enlarged to 25/.04 in the mesial canals and 35/.04 in the distal canals, which were subsequently printed. This procedure eliminated biases associated with the instrumentation for each anatomy.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMicro-CT Scanning\u003c/h3\u003e\n\u003cp\u003eThe 3D replicas were scanned after chemomechanical preparation using a Phoenix Vitomex S240 micro-CT scanner (General Electric, Boston, MA, United States). Scan parameters included an isotropic resolution of 20.0 mm, 105 kV, 70 mA, a full 360-degree rotation around the vertical axis, and a 0.1-mm-thick filter, resulting in a scan time of approximately 25 minutes per replica. These scans were reconstructed using Phoenix-x 3D software (General Electric, Boston, MA, United States). A total of 1250 images per replica were generated with settings such as ring artifact correction at 8, beam hardening correction at 50%, and smoothing set at 6. STL files were generated from these reconstructions using 3D Slicer 5.0.3 software (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.slicer.org\u003c/span\u003e\u003cspan address=\"http://www.slicer.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) to support the internal visualization of the individual anatomical structures.\u003c/p\u003e\n\u003ch3\u003eManufacture of 3D Replicas in Resin\u003c/h3\u003e\n\u003cp\u003eThe STL files of the 3D replicas were imported into AnyCubic PhotonWorkshop software (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.anycubic.es\u003c/span\u003e\u003cspan address=\"https://www.anycubic.es\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) to determine the exact positioning and support required for the printing process. Eleven anatomically identical replicas were then placed in the reservoir of the Anycubic Photon Mono M5s printer (Anycubic Technology Co., Shenzhen, China), which has a resolution of up to 10 \u0026micro;m. The printing file, stored on a SanDisk USB flash drive (Milpitas, California, USA), was used in the printer, which was filled with 200 mL of transparent water-soluble resin (Anycubic Technology Co., Shenzhen, China) with a wavelength of 365\u0026ndash;405 nanometers. The printing process took about 90 minutes.\u003c/p\u003e \u003cp\u003eAfter printing, the replicas were cleaned in hot water using the Anycubic Wash \u0026amp; Cure Plus device (Anycubic Technology Co., Shenzhen, China) to remove excess resin and subjected to a 20-minute polymerization process for final curing. The distal root of each 3D replica was separated to avoid root overlap and noise in the final image analysis. For a comprehensive comparative analysis, each group included eleven 3D resin replicas with mesial (n\u0026thinsp;=\u0026thinsp;22) and distal canals (n\u0026thinsp;=\u0026thinsp;11).\u003c/p\u003e\n\u003ch3\u003eTissue Simulation with Hydrogel Model\u003c/h3\u003e\n\u003cp\u003eA 30G NaviTip needle was used to evenly fill the canal system with an artificial biofilm mixture(AB) formulated with a hydrogel. The hydrogel, which was in a liquid state at the time of injection, had excellent capillary properties and provided uniform distribution with no voids throughout all canal areas.\u003c/p\u003e \u003cp\u003eThe hydrogel was prepared as described by Robinson, Macedo, Verhaagen, Versluis, Cooper, van der Sluis and Walmsley [24], dissolving 3 g of gelatin (Merck, Darmstadt, Germany) and 0.06g of hyaluronan (sodium hyaluronate 95%, Fisher, Waltham, MA, USA) in 45 mL of deionized water at 50\u0026deg;C. In addition, 0.25 g of red food dye (Condi Alimentar, Camarate, Portugal) and 0.1 g of hollow glass beads (Sigma Aldrich, Bornem, Belgium) were added to improve the visibility of AB. The hydrogel was kept at 30\u0026deg;C before injection and solidified within 1 minute at room temperature, a process that was checked for each sample to ensure consistency.\u003c/p\u003e\n\u003ch3\u003eExperimental Groups\u003c/h3\u003e\n\u003cp\u003eForty-four 3D replicas were divided into four groups, each consisting of eleven anatomical models of mesial (n\u0026thinsp;=\u0026thinsp;22) and oval distal canals (n\u0026thinsp;=\u0026thinsp;11) that were activated as follows:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePositive Pressure (Control)\u003c/b\u003e irrigation with an open-ended 30G needle positioned 3 mm up of the WL.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eCordless PUI\u003c/b\u003e Ultra X (Eighteeth, Jiangsu, China), with two activation cycles of 30 seg using the silver tip size 20/.02 positioned 2 mm up of the WL.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eConventional PUI\u003c/b\u003e (Varios 370 lux, NSK, USA) with two activation cycles of 30 seg using the Irrisafe 20/.02 tip (Acteon, Merignac, France) positioned 2 mm up of the WL.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eDL at 980nm\u003c/b\u003e with a power of 1W x 16 plus (Woodpecker Medical Instrument Co., LTD, Guangdong, China) and the 0.2 mm tip positioned 3 mm up the WL. Two activation cycles of 30 seconds were done during the procedure.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eAfter initial photographic documentation, the apical foramen was sealed with TopDam (FGM, Joinville, SC, Brazil) to simulate the vapor lock effect. The teeth were then mounted vertically on a holder designed for intracanal procedures. Each canal was rinsed with 2 mL of water in the mesial roots, followed by supplementary procedural steps. This process was repeated in each canal to reapply the adjunctive methods to improve tissue debridement. For the group using needle and syringe, irrigation was performed with 4 mL of water per canal, using continuous in-and-out movements with an amplitude of 3\u0026ndash;4 mm. A total volume of 4 mL of water was used in each canal, but the apical third ultimately received 8 mL due to confluent anatomy.\u003c/p\u003e \u003cp\u003eIn contrast, in the distal canals, an initial volume of 4 mL of water was introduced, followed by the initiation of the first 30-second cycle. A further 4 mL was introduced into the canal to activate and agitate the solution. Continuous irrigation was performed in the group using the traditional needle and syringe technique, and 8 mL of irrigation fluid was administered. A single operator, an endodontics specialist, conducted the entire procedure.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eTissue Cleaning Efficiency\u003c/h2\u003e \u003cp\u003eBefore and after irrigation, each model underwent microscopic photography (Carl Zeiss, Berlin, Germany) using a special holder to ensure uniform positioning. The initial and final photographic images were opened in the Keynote program (Apple Inc.), and the same size and position were confirmed by superimposing the images. The anatomical structures, such as dentin, were eliminated from the images, leaving only the red-colored root canal system (hydrogel tissue model) in the initial and final samples. For the evaluation, consideration was given to the fact that both main canals had a single apical foramen and an isthmus zone in the apical region connecting both root canals.\u003c/p\u003e \u003cp\u003eThese modified images were integrated into ImageJ 1.50d software (National Institutes of Health, Bethesda, MD) to create binary images, facilitating quantification of tissue surface area (mm\u003csup\u003e2\u003c/sup\u003e) across the entire canal and in the apical, middle, and coronal thirds and the percentage of remaining tissue for each needle group was calculated based on the differences between the pre-and post-irrigation images. \u003cb\u003eStatistical Analysis\u003c/b\u003e\u003c/p\u003e \u003cp\u003eData distribution was assessed using the Shapiro-Wilk normality test and graphical analysis. Given the normal distribution of data, the Student's T-test for independent samples was employed for comparative analyses of the quantitative assessment of remaining tissue between groups. All statistical analyses were conducted using SPSS statistical software (Statistical Package for the Social Sciences 21.0; IBM Corp, Armonk, NY), with the significance level set at 5%.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the data from the quantitative analysis of the remaining tissue, showing no significant differences (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) in the initial amount of tissue between the 3D replicas, suggesting a uniform and comparable filling of the samples.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResidual tissue in mesial canals on the full canal length and the apical, middle, and coronal thirds; expressed as mean (median; range)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeatures (mean-median-range)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eConventional seringe\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWireless PUI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eConventional PUI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLaser 1W\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTissue remants\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAll canal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17453.2 (16862.4; 6997\u0026ndash;26698)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17168.4 (15986.3; 5909\u0026ndash;28076)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17568.1 (16536.3; 6408\u0026ndash;27458)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e17877.4 (16398.2; 6205\u0026ndash;27809)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6800.2 (6375.2; 2012\u0026ndash;16034)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5837.4 (5640.3; 0-13482)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6944.2 (6530.3; 0-14488)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6625.4 (6909.1; 0-16164)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e36.1 (36.3; 11\u0026ndash;62)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29.1 (23.2; 0\u0026ndash;65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e37.3 (37.2; 0\u0026ndash;55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e35.4 (37.4; 0\u0026ndash;80)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eApical\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3749.3 (3692.4; 933\u0026ndash;9456)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3567.3 (3479.3; 628\u0026ndash;8413)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3460.2 (3707.4; 107\u0026ndash;4763)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3549.1 (3208.2; 853\u0026ndash;8514)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1574.3 (870.2; 69-8192)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1246.1 (889.4; 0-3923)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e484.6 (398.2; 0-6052)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1035.3 (965.1; 0-4128)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e42.2 (40.3; 7\u0026ndash;87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30.4 (25.2; 0\u0026ndash;84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.1 (1.3; 0\u0026ndash;87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e29.3 (22.2; 0\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMiddle\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5708.8 (5679.1; 2301\u0026ndash;9934)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5494.2 (5463.4; 2460\u0026ndash;9527)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5413.4 (5254.3; 2614\u0026ndash;9644)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5277.2 (5086.1; 2795\u0026ndash;9547)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1951.3 (1566.2; 0-5603)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e745.2 (500.4; 0-4726)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e777.2 (694.3; 0-4875)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e659.2 (654.3; 0-4769)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34.3 (31.1; 0\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13.4 (10.2; 0\u0026ndash;53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.3 (12.2; 0\u0026ndash;67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12.1 (10.1; 0\u0026ndash;57)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCoronal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInicial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8387.7 (8229.2; 3936\u0026ndash;11567)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8470.4 (8342.1; 3857\u0026ndash;11760)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8153.1 (8174.1; 3466\u0026ndash;11834)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8595.4 (8063.2; 3305\u0026ndash;11618)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2995.8 (2557.1; 0-8219)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2559.4 (2483.1; 0-7609)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2453.6 (2396.3; 0-8539)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2590.3 (2457.2; 0-7997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35.1 (34.1; 0\u0026ndash;84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30.4 (29.1; 0\u0026ndash;75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.2 (33.2; 0\u0026ndash;81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30.1 (34.2; 0\u0026ndash;83)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn the mesial canals, no significant differences in cleaning efficiency were found between the four groups in the full canal length (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). About the apical region of the canal, conventional PUI showed significantly better cleaning performance in the mesial canals of mandibular molars compared to the other groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Specifically, the percentages of residual tissue were as follows: 42.2% for positive pressure irrigation with needle and syringe, 29.3% for DL, 30.4% for cordless PUI, and 14.1% for conventional PUI, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and detailed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFurthermore, wireless PUI and DL exhibited enhanced cleaning efficiency compared to conventional needle irrigation (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), with no significant differences in cleaning efficiency observed between DL and wireless PUI (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eIn the evaluation of the middle third, the analysis revealed no significant differences between the activation techniques (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Nevertheless, all methods proved significantly more effective than conventional irrigation with needle and syringe (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In the coronal third, the study revealed no significant differences in the cleaning ability of the root canals between the groups (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eWhen analyzing the distal oval canals, the percentage of remaining tissue over the entire length of the canal was found to range from 47.2\u0026ndash;37.4% for the needle irrigation and DL. Comparable percentages were observed for the conventional PUI and wireless PUI groups at 38.4% and 39.4%, respectively (see Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In contrast, the irrigation efficiency in the apical region varied between 41.2% in the cordless PUI and 40.3% in the conventional PUI group. Meanwhile, the percentages for positive pressure irrigation and the DL method were reported as 42.3% and 35.2%, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Statistical analysis revealed no significant differences between the groups regarding cleaning effectiveness, neither across the full canal length nor in any third of the canal (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResidual tissue in distal oval canals on the full canal length and the apical, middle, and coronal thirds; expressed as mean (median; range)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeatures (mean-median-range)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eConventional seringe\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWireless PUI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eConventional PUI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLaser 1W\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTissue remants\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAll canal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14166.2 (13983.3; 6695\u0026ndash;22107)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14037.2 (13019.2; 6416\u0026ndash;22449)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14587.3 (13761.2; 6353\u0026ndash;22642)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14163.3 (13045.1; 6522\u0026ndash;22445)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6670.1 (4787.1; 606-17830)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5486.3 (4719.2; 0-13341)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5570.3 (4676.1; 0-18473)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5285.2 (4841.2; 0-15702)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47.2 (41.2; 9\u0026ndash;88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e39.4 (32.3; 0\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e38.4 (26.3; 0\u0026ndash;77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e37.4 (23.1; 0\u0026ndash;91)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eApical\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2788.3 (2483.2; 695\u0026ndash;5483)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2356.4 (2129.3; 678\u0026ndash;5266)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2425.2 (2262.2; 674\u0026ndash;5160)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2420.3 (2396.1; 658\u0026ndash;5381)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1080.4 (945.3; 216\u0026ndash;3131)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e951.3 (835.4; 0-3375)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e970.1 (801.3; 0-3732)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e859.2 (730.2; 0-2549)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e42.3 (41.2; 13\u0026ndash;71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41.2 (31.3; 0\u0026ndash;86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e40.3 (37.2; 0\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e35.2 (31.2; 0\u0026ndash;83)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMiddle\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5620.3 (4720.1; 1700\u0026ndash;8417)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5397.2 (4587.5 (1807\u0026ndash;8646)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5558.4 (4565.2; 1622\u0026ndash;8599)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5424.1 (4583.4; 1738\u0026ndash;8506)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1345.4 (1293.4; 0-5248)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1771.2 (1760.1; 0-5302)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1389.3 (103.2; 0-1168)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1387.4 (1223.1; 0-5919)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e24.1 (21.2; 0\u0026ndash;85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32.3 (21.2; 0\u0026ndash;86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24.4 (22.1; 0\u0026ndash;89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e23.3 (22.2; 0\u0026ndash;88)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCoronal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface(mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInicial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7636.3 (7098.1; 4795\u0026ndash;9894)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7480.2 (7297.3; 4550\u0026ndash;9515)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7780.3 (7584.1; 4798\u0026ndash;9400)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7713.3 (7576.3; 4355\u0026ndash;9502)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3715.2 (3084.3; 0-9255)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3170.2 (2885.4; 0-8616)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3568.4 (3308.2; 0-8692)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3631.2 (3389.1; 0-8415)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔ%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49.1 (45.3; 0\u0026ndash;94)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41.3 (38.2; 0\u0026ndash;97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e45.3 (41.2; 0\u0026ndash;96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e47.3 (43.2; 0\u0026ndash;96)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe objective of this study was to evaluate the cleaning effectiveness of different agitation and activation techniques in root canals that have undergone conservative preparation.\u003c/p\u003e \u003cp\u003eThe analysis has primarily highlighted the limitations of using traditional needles and syringes for root canal irrigation. Although these conventional methods are commonly used, the present study shows their suboptimal cleaning efficiency when minimal instrumentation was performed in complex anatomies, especially in the apical third of the root canal.\u003c/p\u003e \u003cp\u003eConventional root canal irrigation with positive pressure is mainly limited by its inability to remove tissue thoroughly [3], particularly in complex root canal anatomies [2]. This study emphasizes this limitation, showing that conventional needle irrigation is significantly less efficient at tissue removal than alternative techniques. This discrepancy is especially evident in the apical region of the mesial canals of mandibular molars, where conventional needle irrigation leaves a significantly higher percentage of residual tissue (42.2%) compared to adjunctive approaches.\u003c/p\u003e \u003cp\u003eThe findings suggest that conventional needle irrigation remains a foundational technique during chemomechanical preparation. Still, it is essential to emphasize that it needs to be complemented by more advanced techniques such as PUI or DL, specifically when dealing with teeth featuring intricate anatomical features and minimal instrumentation [25].\u003c/p\u003e \u003cp\u003eHowever, It is important to point out that in the present study, the mesial canals were instrumented up to a size 25/.04. Instrumentation of the root canal to a larger size, such as #35, is crucial for several reasons when using a needle and syringe for irrigation [22, 26]. Firstly, enlarging the canal size facilitates greater fluid dynamics, allowing for increased flow and better access of the irrigant to the canal's entirety [22], including its apical region [26]. This is particularly important because the effectiveness of needle and syringe irrigation heavily relies on the physical flow of the irrigant to remove tissue debris and disinfect the canal [27]. Larger instrumentation sizes create a wider canal space, improving the penetrability and flow of the irrigant [23], thus enhancing the renewal and exchange of the solution within the canal system [28].\u003c/p\u003e \u003cp\u003eThe mechanical limitation of a needle and syringe is primarily its inability in narrower canals to agitate the irrigant sufficiently within the complex root canal system and achieve optimal flow [29], especially in the apical third, reducing its efficacy in tissue removal and disinfection [23].\u003c/p\u003e \u003cp\u003eThe study's results indicate that conventional PUI outperformed other methods in the mesial canals of mandibular molars, with significantly less residual tissue (14.1% for conventional PUI compared to 42.2% for needle and syringe, 29.3% for DL, and 30.4% for cordless PUI), highlight the effectiveness of PUI in challenging areas. The results of this study agree with another where greater cleaning was observed when ultrasonic activation was used in canals with smaller apical preparations compared to using only a conventional syringe [25].\u003c/p\u003e \u003cp\u003eSurprisingly, traditional PUI performed significantly better than wireless PUI in the apical region of the root canal. Although both methods are based on similar principles, the results of this study suggest that conventional PUI has greater activation and agitation capabilities than wireless PUI. Future studies should validate these findings, evaluating the wavelengths and powers of both methods.\u003c/p\u003e \u003cp\u003eThe similar performance of wireless PUI and DL, both showing enhanced efficiency over needle irrigation, underscores the importance of selecting advanced irrigation methods to optimize root canal cleaning. PUI, by generating acoustic streaming and cavitation effects [18], and DL, by activating irrigants and inducing tissue dissolution through rapid temperature increases and the formation of vaporized bubbles, [17] may improve the cleaning efficacy. These advanced techniques facilitate deeper penetration of irrigants into difficult-to-reach areas, significantly improving cleaning efficacy in the root canal system [17, 25].\u003c/p\u003e \u003cp\u003eIn the middle third of the root canals, all activation techniques proved significantly more effective than conventional irrigation with a needle and syringe, underlining the latter's inefficiency in removing tissue, probably because of the narrower space that limits their action. However, no significant differences were found among the activation methods in this region. This indicates that while activation methods are advantageous, the choice between them may not significantly impact cleaning outcomes in the middle third of the root canals.\u003c/p\u003e \u003cp\u003eIn the coronal third, the study did not reveal significant differences in cleaning ability among the various groups. This suggests that conventional needle irrigation may be comparably effective in this region to activation methods, and the choice of technique may be less critical.\u003c/p\u003e \u003cp\u003eHowever, caution is required when interpreting the current study's findings. First, no comparison was made between smaller and larger apical diameters to determine whether activation and agitation techniques could replace apical enlargement in the mesial roots of mandibular molars or whether they should merely serve as supplementary methods to improve tissue removal and disinfection efficacy.\u003c/p\u003e \u003cp\u003eSecond, the main goal in managing apical periodontitis is the eradication of bacterial biofilm in the root canal system [1]. However, increasing emphasis is being placed on minimally invasive endodontic treatments, which, while increasing fracture resistance [30], could potentially compromise disinfection [31] and, consequently, treatment outcomes.\u003c/p\u003e \u003cp\u003eA Previous study showed that when root canals are prepared to an apical size of 20 or 25, NaOCl cannot effectively reach the working length when using syringes and needles [29]. To address this problem, in vitro studies have developed activation and agitation irrigation strategies to ensure thorough disinfection of minimally prepared canals [25, 32]. To date, no clinical studies provide evidence of conducting minimal root canal preparations and relying on agitation and activation techniques to compensate for disinfection.\u003c/p\u003e \u003cp\u003eExisting evidence suggests that larger apical diameters allow better renewal of the irrigant in the apical third of the root canal [23], resulting in enhanced disinfection [33] and, consequently, a higher success rate in endodontic treatment [34]. Future clinical investigations must validate the efficacy of minimally shaped canals in complex anatomies such as mandibular molars using adjunctive approaches, particularly regarding their disinfection ability compared to larger apical diameters. These findings could serve as a surrogate endpoint for the overall success of endodontic treatment.\u003c/p\u003e \u003cp\u003eIn this study, an important aspect was comparing eleven different anatomical variations of natural mandibular molar teeth. These molars were divided into four groups, resulting in forty-four 3D resin replicas. This meticulous approach helped us minimize any potential biases arising from anatomical differences, and it is more representative of studies on extracted natural teeth where different anatomies are utilized, as opposed to using a single anatomy repeatedly to compare different methods.\u003c/p\u003e \u003cp\u003eFurthermore, an interesting finding was the consistency in the amount of initial tissue in the samples. Our preliminary analysis revealed no significant differences in the presence of tissue when comparing the different groups. It is also worth noting that the mandibular molars we selected with Class II Vertucci anatomy in the mesial canals and oval-shaped in the distal canals provided a representative challenge for evaluating agitation and activation techniques.\u003c/p\u003e \u003cp\u003eOval canals present unique challenges due to their shape, which often leaves recesses not adequately reached by rotary instruments [10], resulting in incomplete debridement and inadequate disinfection [35]. This is compounded by the difficulty of achieving thorough irrigation [10], which is crucial for removing tissue remnants and bacterial biofilms from these complex anatomical structures [10, 25].\u003c/p\u003e \u003cp\u003eThe results of the present study showed that in the distal oval canals, the percentage of tissue remaining along the entire length of the canal ranged from 47.2\u0026ndash;37.4% for the needle irrigation and DL groups. Comparable percentages were observed for the conventional PUI and wireless PUI groups at 38.4% and 39.4%, respectively, and no significant differences were observed in any third of the canal between the groups evaluated. These findings suggest that none of the techniques studied achieved greater tissue cleaning in oval canals than conventional syringes.\u003c/p\u003e \u003cp\u003eThe results of this study highlight the inherent limitations resulting from the canal's oval shape, which can hinder the cleaning effectiveness of even the most sophisticated irrigation methods. These findings are consistent with previous studies that found no significant differences when using different activation and agitation techniques in oval canals [14, 36].\u003c/p\u003e \u003cp\u003eThese results are critical for several reasons. First, they suggest that while supplementary techniques can play a role in endodontic treatment, their ability to significantly outperform traditional irrigation methods in oval canals is limited [14]. This limitation is particularly pronounced given the shape of these canals, which inherently complicates the task of comprehensive tissue removal [10]. Secondly, the percentages of remaining tissue suggest that a substantial amount of the canal surface remains uncleaned, regardless of the irrigation technique used [14]. This scenario could compromise the disinfection process, leaving the canal system susceptible to persistent infection and endodontic treatment failure [37].\u003c/p\u003e \u003cp\u003eIt is crucial to emphasize that regardless of the specific technique employed or the type of anatomical variation considered, none of the procedures completely removed the tissue, particularly in the apical third of the canal. The apical root canal area is crucial in infection control, as bacteria in this region can contribute to post-treatment apical periodontitis [38]. However, the complete tissue removal from this area remains challenging with current techniques. Our findings are consistent with previous studies that have also reported a higher incidence of residual tissue and/or bacteria in the apical region of mesial and distal canals of mandibular molars [2, 3, 10].\u003c/p\u003e \u003cp\u003eIn addition, tissue persistence may interfere with the proper filling of the root canal, which may lead to treatment failure in necrotic teeth [39]. As demonstrated in this study, the main reason for tissue persistence is the limitation of existing techniques in the reliable delivery of irrigants to different regions of the root canal, particularly those with complex anatomical features. These findings emphasize the urgent need for innovative methods that can predictably optimize tissue removal throughout the entire root canal system.\u003c/p\u003e \u003cp\u003eAlthough an innovative approach was taken in this study, in which various natural tooth anatomies were 3D printed, it is essential to recognize its limitations. First, water served as an irrigant throughout the experiment, which means that the evaluation primarily focused on evaluating the mechanical aspects of the techniques and did not consider the chemical properties or capabilities of the irrigant. F Furthermore, utilizing resin replicas instead of natural teeth might lead to variations in irrigant diffusion and tissue removal. In the resin model, there is no buffering activity of the dentin, which happens in the natural teeth when sodium hypochlorite is used. Hence, the results obtained in this study by using distilled water may be overestimated. Finally, this is an in vitro study, so caution should be exercised when extrapolating these findings to real clinical scenarios.\u003c/p\u003e \u003cp\u003eIn conclusion, conventional PUI performed better than other methods in cleaning the mesial canals of mandibular molars, especially in the apical region. Cordless PUI and DL proved to be promising alternatives that offered better cleaning compared to conventional needle irrigation. All methods proved to be superior to conventional irrigation in the middle third of the canal. However, no significant differences were found between the tested groups in the distal oval canals, suggesting that the choice of irrigation technique may have less impact on cleaning efficiency in these canals.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAlissa Tiscare\u0026ntilde;o\u003c/strong\u003e:\u0026nbsp;Investigation, Methodology, Software.\u003cstrong\u003e\u0026nbsp;P.S. Ortolani-Seltenerich:\u0026nbsp;\u003c/strong\u003eInvestigation, Supervision.\u0026nbsp;\u003cstrong\u003eAna Ram\u0026iacute;rez-Mu\u0026ntilde;oz\u003c/strong\u003e: Data curation.\u0026nbsp;\u003cstrong\u003eOmar P\u0026eacute;rez-Ron\u003c/strong\u003e: Reviewing and Editing.\u0026nbsp;\u003cstrong\u003ePedro M. Mendez S\u003c/strong\u003e:\u0026nbsp;Software, Data curation.\u003cstrong\u003e\u0026nbsp;Carmen Leal-Moya\u003c/strong\u003e:\u0026nbsp;Conceptualization, Supervision.\u003cstrong\u003eGaya C. S. Vieira\u003c/strong\u003e\u003cem\u003e:\u003c/em\u003e Conceptualization, Reviewing and Editing.\u003cstrong\u003eAlejandro R. P\u0026eacute;rez\u003c/strong\u003e:\u0026nbsp;Writing- Reviewing and Editing, Conceptualization, Supervision.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate:\u0026nbsp;\u003c/strong\u003eAs no human or animal teeth, tissues, or cells were used, it was not necessary to obtain an ethics committee to conduct the current study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eNo funding was obtained for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e The authors deny any conflicts of interest.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA.T: Investigation, Methodology, Software. P.S.O.S: Investigation, Supervision. A.R-M: Data curation. O.P-R: Reviewing and Editing. P.M. M.S: Software, Data curation. C.L-M: Conceptualization, Supervision. G.C. S.V: Conceptualization, Reviewing and Editing. A.R.P: Writing- Reviewing and Editing, Conceptualization, Supervision.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data are available upon reasonable request from the authors\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZandi H, Petronijevic N, Mdala I, Kristoffersen AK, Enersen M, R\u0026ocirc;\u0026ccedil;as IN, Siqueira JF Jr., \u0026Oslash;rstavik D (2019) Outcome of Endodontic Retreatment Using 2 Root Canal Irrigants and Influence of Infection on Healing as Determined by a Molecular Method: A Randomized Clinical Trial. J Endod. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2019.05.021\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2019.05.021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eP\u0026eacute;rez AR, Ricucci D, Vieira GCS, Provenzano JC, Alves FRF, Marceliano-Alves MF, R\u0026ocirc;\u0026ccedil;as IN, Siqueira JF Jr. (2020) Cleaning, Shaping, and Disinfecting Abilities of 2 Instrument Systems as Evaluated by a Correlative Micro-computed Tomographic and Histobacteriologic Approach. J Endod 46:846\u0026ndash;857. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2020.03.017\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2020.03.017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiqueira JF Jr., P\u0026eacute;rez AR, Marceliano-Alves MF, Provenzano JC, Silva SG, Pires FR, Vieira GCS, R\u0026ocirc;\u0026ccedil;as (2018) IN and Alves FRF What happens to unprepared root canal walls: a correlative analysis using micro-computed tomography and histology/scanning electron microscopy. Int Endod J 51:501\u0026ndash;508. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/iej.12753\u003c/span\u003e\u003cspan address=\"10.1111/iej.12753\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiqueira JF Jr., R\u0026ocirc;\u0026ccedil;as IN, Marceliano-Alves MF, Perez AR, Ricucci D (2018) Unprepared root canal surface areas: causes, clinical implications, and therapeutic strategies. Braz Oral Res 32(suppl 1):e65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1590/1807-3107bor-2018.vol32.0065\u003c/span\u003e\u003cspan address=\"10.1590/1807-3107bor-2018.vol32.0065\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlves FR, Andrade-Junior CV, Marceliano-Alves MF, Perez AR, Rocas IN, Versiani MA, Sousa-Neto MD, Provenzano JC, Siqueira JF Jr. (2016) Adjunctive Steps for Disinfection of the Mandibular Molar Root Canal System: A Correlative Bacteriologic, Micro-Computed Tomography, and Cryopulverization Approach. J Endod 42:1667\u0026ndash;1672. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2016.08.003\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2016.08.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePaiva SSM, Siqueira JE, Rocas IN, Carmo FL, Ferreira DC, Curvelo JAR, Soares RMA, Rosado AS (2012) Supplementing the Antimicrobial Effects of Chemomechanical Debridement with Either Passive Ultrasonic Irrigation or a Final Rinse with Chlorhexidine: A Clinical Study. J Endod 38:1202\u0026ndash;1206. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2012.06.023\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2012.06.023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVianna ME, Horz HP, Gomes BP, Conrads G (2006) In vivo evaluation of microbial reduction after chemo-mechanical preparation of human root canals containing necrotic pulp tissue. Int Endod J 39:484\u0026ndash;492. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1365-2591.2006.01121.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2591.2006.01121.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNeves MA, Provenzano JC, R\u0026ocirc;\u0026ccedil;as IN, Siqueira JF Jr. (2016) Clinical antibacterial effectiveness of root canal preparation with reciprocating single-instrument or continuously rotating multi-instrument systems. J Endod 42:25\u0026ndash;29. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2015.09.019\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2015.09.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSj\u0026ouml;gren U, Figdor D, Persson S, Sundqvist G (1997) Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 30:297\u0026ndash;306\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLacerda M, Marceliano-Alves MF, P\u0026eacute;rez AR, Provenzano JC, Neves MAS, Pires FR, Gon\u0026ccedil;alves LS, R\u0026ocirc;\u0026ccedil;as (2017) IN and Siqueira JF, Jr. Cleaning and shaping oval canals with 3 instrumentation systems: a correlative micro-computed tomographic and histologic study. J Endod 43:1878\u0026ndash;1884. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2017.06.032\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2017.06.032\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeller RN, Niemczyk SP, Kim S (1995) Incidence and position of the canal isthmus. Part 1. Mesiobuccal root of the maxillary first molar. J Endod 21:380\u0026ndash;383\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMannocci F, Peru M, Sherriff M, Cook R, Pitt Ford TR (2005) The isthmuses of the mesial root of mandibular molars: a micro-computed tomographic study. Int Endod J 38:558\u0026ndash;563. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1365-2591.2005.00994.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2591.2005.00994.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarris SP, Bowles WR, Fok A, McClanahan SB (2013) An anatomic investigation of the mandibular first molar using micro-computed tomography. J Endod 39:1374\u0026ndash;1378. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2013.06.034\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2013.06.034\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlves FR, Almeida BM, Neves MA, Moreno JO, Rocas IN, Siqueira JF Jr. (2011) Disinfecting oval-shaped root canals: effectiveness of different supplementary approaches. J Endod 37:496\u0026ndash;501. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2010.12.008\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2010.12.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu MK, R'Oris A, Barkis D, Wesselink PR (2000) Prevalence and extent of long oval canals in the apical third. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 89:739\u0026ndash;743\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePaqu\u0026eacute; F, Balmer M, Attin T, Peters OA (2010) Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. J Endod 36:703\u0026ndash;707. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2009.12.020\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2009.12.020\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHongo T, Watanabe S, Yao K, Satake K, Okiji T (2019) Evaluation of cleaning efficacy-related properties of root canal irrigant activation using a computer-controlled hot tip powered with a diode laser. Asian Pac J Dentistry 19:9\u0026ndash;15. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.47416/apjod.19-0256\u003c/span\u003e\u003cspan address=\"10.47416/apjod.19-0256\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan der Sluis LW, Versluis M, Wu MK, Wesselink PR (2007) Passive ultrasonic irrigation of the root canal: a review of the literature. Int Endod J 40:415\u0026ndash;426. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1365-2591.2007.01243.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2591.2007.01243.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVendramini Y, Salles A, Portella FF, Brew MC, Steier L, de Figueiredo JAP, Bavaresco CS (2020) Antimicrobial effect of photodynamic therapy on intracanal biofilm: A systematic review of in vitro studies. Photodiagn Photodyn Ther 32:102025. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.pdpdt.2020.102025\u003c/span\u003e\u003cspan address=\"10.1016/j.pdpdt.2020.102025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShrestha A, Kishen A (2014) Antibiofilm efficacy of photosensitizer-functionalized bioactive nanoparticles on multispecies biofilm. J Endod 40:1604\u0026ndash;1610. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2014.03.009\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2014.03.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKishen A, Asundi A (2002) Photomechanical investigations on post endodontically rehabilitated teeth. J Biomed Opt 7:262\u0026ndash;270. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1117/1.1463046\u003c/span\u003e\u003cspan address=\"10.1117/1.1463046\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, Van der Sluis LW (2010) The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model. Int Endod J 43:874\u0026ndash;881. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1365-2591.2010.01761.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2591.2010.01761.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodrigues RCV, Zandi H, Kristoffersen AK, Enersen M, Mdala I, \u0026Oslash;rstavik D, R\u0026ocirc;\u0026ccedil;as (2017) IN and Siqueira JF, Jr. Influence of the apical preparation size and the irrigant type on bacterial reduction in root canal-treated teeth with apical periodontitis. J Endod 43:1058\u0026ndash;1063. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2017.02.004\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2017.02.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRobinson JP, Macedo RG, Verhaagen B, Versluis M, Cooper PR, van der Sluis LWM, Walmsley AD (2018) Cleaning lateral morphological features of the root canal: the role of streaming and cavitation. Int Endod J 51 Suppl 1e55\u0026ndash;e64. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/iej.12804\u003c/span\u003e\u003cspan address=\"10.1111/iej.12804\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee OYS, Khan K, Li KY, Shetty H, Abiad RS, Cheung GSP, Neelakantan P (2019) Influence of apical preparation size and irrigation technique on root canal debridement: a histological analysis of round and oval root canals. Int Endod J 52:1366\u0026ndash;1376. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/iej.13127\u003c/span\u003e\u003cspan address=\"10.1111/iej.13127\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, Van der Sluis LW (2010) The effect of root canal taper on the irrigant flow: evaluation using an unsteady Computational Fluid Dynamics model. Int Endod J 43:909\u0026ndash;916. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1365-2591.2010.01767.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2591.2010.01767.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoutsioukis C, Lambrianidis T, Verhaagen B, Versluis M, Kastrinakis E, Wesselink PR, van der Sluis LW (2010) The effect of needle-insertion depth on the irrigant flow in the root canal: evaluation using an unsteady computational fluid dynamics model. J Endod 36:1664\u0026ndash;1668. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2010.06.023\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2010.06.023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiqueira JF Jr., Araujo MC, Garcia PF, Fraga RC, Dantas CJ (1997) Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J Endod 23:499\u0026ndash;502. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0099-2399(97)80309-3\u003c/span\u003e\u003cspan address=\"10.1016/S0099-2399(97)80309-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoutsioukis C, Gutierrez Nova P (2021) Syringe Irrigation in Minimally Shaped Root Canals Using 3 Endodontic Needles: A Computational Fluid Dynamics Study. J Endod 47:1487\u0026ndash;1495. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2021.06.001\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2021.06.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePlotino G, Grande NM, Isufi A, Ioppolo P, Pedull\u0026agrave; E, Bedini R, Gambarini G, Testarelli L (2017) Fracture Strength of Endodontically Treated Teeth with Different Access Cavity Designs. J Endod 43:995\u0026ndash;1000. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2017.01.022\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2017.01.022\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVieira GCS, P\u0026eacute;rez AR, Alves FRF, Provenzano JC, Mdala I, Siqueira JF Jr., R\u0026ocirc;\u0026ccedil;as (2020) IN Impact of Contracted Endodontic Cavities on Root Canal Disinfection and Shaping. J Endod 46:655\u0026ndash;661. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2020.02.002\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2020.02.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTeed C, Hussein H, Kishen A (2023) Synchronized Microbubble Photodynamic Activation to Disinfect Minimally Prepared Root Canals. J Endod 49:198\u0026ndash;204. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2022.12.003\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2022.12.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCard SJ, Sigurdsson A, \u0026Oslash;rstavik D, Trope M (2002) The effectiveness of increased apical enlargement in reducing intracanal bacteria. J Endod 28:779\u0026ndash;783. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00004770-200211000-00008\u003c/span\u003e\u003cspan address=\"10.1097/00004770-200211000-00008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFatima S, Kumar A, Andrabi S, Mishra SK, Tewari RK (2021) Effect of Apical Third Enlargement to Different Preparation Sizes and Tapers on Postoperative Pain and Outcome of Primary Endodontic Treatment: A Prospective Randomized Clinical Trial. J Endod 47:1345\u0026ndash;1351. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2021.05.010\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2021.05.010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiqueira JF Jr., Alves FR, Almeida BM, de Oliveira JC, Rocas IN (2010) Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. J Endod 36:1860\u0026ndash;1865. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2010.08.001\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2010.08.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe-Deus G, Belladonna FG, de Siqueira Zuolo A, Perez R, Carvalho MS, Souza EM, Lopes RT, Silva E (2019) Micro-CT comparison of XP-endo Finisher and passive ultrasonic irrigation as final irrigation protocols on the removal of accumulated hard-tissue debris from oval shaped-canals. Clin Oral Investig 23:3087\u0026ndash;3093. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00784-018-2729-y\u003c/span\u003e\u003cspan address=\"10.1007/s00784-018-2729-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArnold M, Ricucci D, Siqueira JF Jr. (2013) Infection in a complex network of apical ramifications as the cause of persistent apical periodontitis: a case report. J Endod 39:1179\u0026ndash;1184. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2013.04.036\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2013.04.036\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRicucci D, Siqueira JF Jr., Bate AL, Pitt Ford TR (2009) Histologic investigation of root canal-treated teeth with apical periodontitis: a retrospective study from twenty-four patients. J Endod 35:493\u0026ndash;502. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2008.12.014\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2008.12.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiqueira JF Jr., Antunes HS, P\u0026eacute;rez AR, Alves FRF, Mdala I, Silva E, Belladonna FG, R\u0026ocirc;\u0026ccedil;as (2020) IN The Apical Root Canal System of Teeth with Posttreatment Apical Periodontitis: Correlating Microbiologic, Tomographic, and Histopathologic Findings. J Endod 46:1195\u0026ndash;1203. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.joen.2020.05.020\u003c/span\u003e\u003cspan address=\"10.1016/j.joen.2020.05.020\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Chemomechanical preparation, passive ultrasonic irrigation, diode laser, cleaning effectiveness, root canal","lastPublishedDoi":"10.21203/rs.3.rs-5355986/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5355986/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose:\u003c/strong\u003e This study aimed to evaluate the efficacy of cleaning in minimally shaped mesial and oval distal canals of 3D models of mandibular molars, focusing on positive pressure irrigation, wireless and conventional passive ultrasonic irrigation (PUI), and diode laser (DL) at 980 nm.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e Forty-four replicas of natural mandibular molars were divided into four groups of eleven 3D resin models with apical size 25/.04 mesial (n=22) and 35/.04 oval distal canals (n=11) to evaluate different irrigation methods. Each root canal was uniformly filled with an artificial hydrogel to simulate a biofilm mixture. Following this preparation, the specified irrigation techniques were applied to the respective groups. Quantitative evaluations of pre- and post-irrigation images were performed to assess the efficiency of tissue removal along the entire length of the canal and in the apical, middle, and coronal thirds.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The findings revealed no significant differences in the initial amount of tissue between the samples, indicating uniform filling. In the apical region of mesial canals, conventional PUI showed the highest cleaning efficiency (14.1% residual tissue), significantly outperforming the other methods (p\u0026lt;0.05). Cordless PUI and DL also surpassed positive pressure irrigation, leaving 30.4% and 29.3% residual tissue, respectively, compared to 42.2% with positive pressure. In the middle third, all methods tested performed better than needle irrigation (p\u0026lt;0.05), but there were no significant differences in the coronal third or over the full canal length. Distal oval canals showed no significant differences in cleaning effectiveness among methods.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e Although no single method was superior in full canal length, supplementary techniques such as PUI and DL offer potential benefits over conventional irrigation methods, particularly in the apical third of the canal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Relevance: \u003c/strong\u003eComplementary approaches such as conventional PUI and diode laser at 980 nm showed superior cleaning efficiency, particularly in the apical third. These results suggest their integration could improve cleaning effectiveness in minimally instrumented mesial canals.\u003c/p\u003e","manuscriptTitle":"Efficacy of Advanced Cleaning Approaches in 3D Mandibular Molar Models: A Laboratory Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-20 15:01:17","doi":"10.21203/rs.3.rs-5355986/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"78c17778-5fef-48c9-9b52-034d3025fe18","owner":[],"postedDate":"November 20th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-03-28T06:53:48+00:00","versionOfRecord":[],"versionCreatedAt":"2024-11-20 15:01:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5355986","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5355986","identity":"rs-5355986","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}