In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis

In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis | 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 In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis Niloufar Entezari Moghaddam, Farmehr Fadaei Tirani, Mohammad Aghaali, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6710371/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Nov, 2025 Read the published version in BMC Oral Health → Version 1 posted 14 You are reading this latest preprint version Abstract Background Primary teeth are necessary for mastication, speech, and guiding the eruption of permanent teeth. Dental caries often requires pulpectomy treatment to preserve these teeth. The success of pulpectomy depends on root canal obturation quality. This study aimed to compare the filling quality of zinc oxide-eugenol (ZOE) and Endofloss using lentulo and reverse rotary techniques, assessed by micro-computed tomography. Methods An in vitro study was conducted on 32 extracted human primary mandibular second molars. Teeth were randomly divided into four groups (n = 8) based on obturation material (ZOE or Endofloss) and technique (lentulo spiral or reverse rotary file). After standard canal preparation, obturation was performed. Micro-computed tomography assessed the quality of obturation by measuring the percentage of void and filling volume. Statistical analysis was performed using ANOVA test (p < 0.05). Results The lowest total void percentage was observed in the (ZOE + Lentulo) group (22.61 ± 9.00), and the highest in the (Endofloss|+Lentulo) group (35.97 ± 5.90). ZOE obturation resulted in lower voids (24.09 ± 8.50) compared to Endofloss (30.70 ± 8.50). The reverse rotary technique showed non significant lower voids (25.50 ± 7.60) than Lentulo (29.29 ± 10.10) (p = 0.181). A significant interaction effect was observed between material and technique in term of total voids (p = 0.021). (ZOE + Lentulo) group showed the highest filling volume (76.50 ± 9.10), while(Endofloss + Lentulo) had the lowest (64.02 ± 5.90). ZOE yielded higher filling volume (75.47 ± 8.50) compared to Endofloss (69.22 ± 8.50), with a significant material effect (p = 0.034), but no significant effect of technique (p = 0.138). Conclusion ZOE + Lentulo technique provided the most root canal obturation quality, while Endofloss + Lentulo showed the least quality. The root canal filling quality was more influenced by the obturation material than the technique used. Root Canal Therapy Deciduous teeth Endofloss Zinc Oxide-Eugenol Micro-Computed Tomography Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Eruption of primary teeth is a crucial process in human development and plays a significant role in mastication, guiding the eruption of permanent succedaneous teeth, jaws growth, digestion, and speech development ( 1 , 2 ). Loss of primary teeth due to caries is common. Dental caries is the most prevalent chronic disease worldwide and one of the most common diseases in children ( 3 , 4 ). This multifactorial disease is caused by bacteria and their acid production. Factors such as improper nutrition, unfavorable socioeconomic status, and poor oral hygiene increase the risk of primary tooth caries ( 5 ). In children, this disease can lead to nutritional problems, growth impairment, speech difficulties, and compromised permanent teeth health ( 6 ). Untreated primary teeth will be lost. Preserving posterior primary teeth until the eruption of their permanent successors is crucial, as their early loss can result in space deficiency, jaws and dental developmental issues, malnutrition, and aesthetic problems ( 7 ). Pulpal therapy in primary teeth is divided into vital pulp therapy (for healthy pulp or reversible pulpitis) and non-vital pulp therapy (for irreversible pulpitis or pulp necrosis) ( 8 ). For primary teeth with irreversible pulpitis, chronic inflammation, or necrosis in the radicular pulp, pulpectomy is performed. The aim of this treatment is to preserve a tooth that would otherwise be extracted. The success of this procedure depends on microbial reduction, proper canal preparation, irrigation, and adequate sealing by the filling material ( 9 ). An ideal root canal filling material should possess sufficient adhesion, ease of application, biocompatibility with vital tissues and the permanent tooth germ, a resorption rate similar to that of primary root resorption, antibacterial properties, radio opacity, no tooth discoloration, and rapid resorption if extruded beyond the apex. To date, no single material fully meets all these criteria ( 10 ). Various materials, including zinc oxide-eugenol (ZOE) and combination pastes (Endofloss), are used for filling root canals of primary teeth. Although Zinc oxide-eugenol (ZOE) is an age-old material with a palliative effect, it has drawbacks such as a slow resorption rate and potential tissue irritation ( 11 ). Combination pastes (Endofloss) have a composition similar to calcium hydroxide and iodoform (Vitapex) and ZOE, exhibiting good antimicrobial properties. Their resorption rate is close to the rate of root resorption. However, they may cause tooth discoloration ( 12 ). In addition to the material utilized, the quality of the root canal filling and achieving a homogenous and void-free obturation is a key factor in the success of pulpectomy in primary teeth ( 13 ). Various techniques, such as endodontic pressure syringes, lentulo spirals (manual and engine-driven), and rotary (reverse) instruments, have been developed for filling root canals of primary teeth ( 14 ). Although the reverse using of nickel-titanium rotary instruments for intracanal drug delivery in permanent teeth has been studied, limited research exists in this area for primary teeth. Various methods can be used to evaluate the quality of root canal filling, such as conventional periapical radiography, histological sectioning, scanning electron microscopy, stereomicroscopy, and micro-computed tomography (micro-CT). Micro-CT imaging is recognized as the most accurate non-invasive method for evaluating root canal treatment outcomes, providing three-dimensional assessment of root anatomy and differentiation of materials, canal structure, and potential voids ( 15 ). Therefore, the aim of the present study is to compare the filling quality of primary teeth root canals using two instruments, lentulo spirals and reverse rotary files, with two materials, ZOE and Endofloss, utilizing micro-computed tomography. Methods & Materials This experimental in vitro study was approved by Research Ethics Committee of Qom university of medical sciences and conducted on 32 extracted human primary second mandibular molar teeth (E) in Qom dental faculty, Qom, Iran in 2023–2024. According to previous studies and using a two-mean comparison formula with α = 0.05, β = 0.2, σ₁ = 0.113, σ₂ = 0.04, µ₁ = 0.1, and µ₂ = 0.32, the sample size was calculated as 8 per group ( 15 ). The inclusion criteria were a root length of 7 to 12 mm, the absence of any caries and internal or external root resorption in the tooth, the absence of fractures and cracks in the root and crown, and the absence of root canal calcifications. The exclusion criteria included a prolonged time interval between tooth extraction and the start of the preparation procedures and the presence of pulp stones in the pulp chamber. All criteria were confirmed by visual inspection and periapical radiography. Samples preparation After removing excess tissue attached to the teeth by low-speed prophylactic brushing, all extracted teeth were immersed in a 0.5% thymol solution in distilled water for 48 hours for disinfection and then stored in distilled water for subsequent procedures ( 16 ). Root canal preparation To create access cavities in the teeth, the pulp chamber roof was completely removed using a high-speed diamond bur, and direct access to the orifices of all canals was established. After complete removal of the pulp tissue using a barbed broach and Hedstrom files (Mani, Japan), the canal length was assessed using a #10 K-file (Mani, Japan) until it reached the point of penetration, and the working length (WL) of the roots was determined to be 1 mm behind the apex. Subsequently, all teeth were surrounded by red wax around the root apex (for easier identification in radiographs) and then mounted in acrylic resin. A standard preparation technique was used for canal cleaning and shaping. After each filing, the canals were irrigated with a 1% normal saline solution. Following complete root preparation and shaping, the teeth were randomly divided into 4 groups (n = 8 in each group): * Group 1: Teeth were obturated with ZOE (Kemdent Wiltshire, England) using a #25 Lentulo spiral (Medin, South Korea) attached to a low-speed handpiece. To prevent changes in the consistency of the ZOE material, the powder and liquid were mixed according to the manufacturer's instructions. To ensure accurate WL determination and ease of operation, half the length of the Lentulo spiral was cut (due to the shorter length of primary tooth canals), and the working length was then marked with a rubber stop. The Lentulo spiral was coated with the material and inserted into the canals, then moved along all canal walls at low speed. This process was repeated 3 to 4 times in each canal. * Group 2: Teeth were obturated with Endofloss (Sanlor laboratories, USA) using a #25 Lentulo spiral filler attached to a low-speed handpiece. The mixing of the powder, liquid, and accelerator of Endofloss was performed according to the manufacturer's instructions. * Group 3: Teeth were obturated with ZOE using an M3 Immature rotary file (UDG company, China) with reverse rotation. A #25 rotary file with a length of 16 mm and a rubber stop set at the canal length was used. The file, coated with the filling material, was inserted into the canal to the working length with a reverse rotation motion and moved along the canal walls. This process was repeated 3 to 4 times. * Group 4: Teeth were obturated with Endofloss using an M3 Immature rotary file with reverse rotation. To prevent bias due to operator fatigue, only 5 teeth were prepared and then obturated in each session. All preparation and obturation procedures were performed by a single professional operator to avoid inter-operator variability, and one person was present monitoring throughout all stages to ensure consistency in the preparation and obturation procedures across all teeth and groups. After completion of the root canal filling procedures, micro-CT imaging (Lotus-NDT, Behin Negareh, Iran) was used to evaluate the quality of the filling in the teeth of each group. All necessary information was recorded on a pre-set checklist. The percentage volume of the filling material in the canals and the percentage volume of voids (areas free of filling material) were determined for each canal using micro-CT imaging ( 17 ). The data were entered into SPSS-26 software, and statistical analysis was performed at both descriptive and inferential levels. Descriptive statistics included using the means and standard deviations, along with relevant graphical representations. Inferential analysis involved the use of mean comparison tests and ANOVA to analyze the results at a significance level of p < 0.05. Results Evaluation of total void, void in and void out: The mean percentage of total void (void in + void out) in mm³ was lowest in (ZOE + Lentulo technique) group (22.61 ± 9.00) and highest in (Endofloss + Lentulo technique) group (35.97 ± 5.90). Moreover, the mean percentage of total void in teeth obturated with ZOE (24.09 ± 8.50) was overally lower than in teeth obturated with Endofloss (30.70 ± 8.50). Additionally, the mean percentage of total void using the reverse rotary obturation technique (25.50 ± 7.60) was lower than that using the Lentulo technique (29.29 ± 10.10). The overall mean percentage of total void across all obturated teeth was 27.39 ± 9.00. The mean percentages of void in and void out in (ZOE + Lentulo technique) group were the lowest (14.05 ± 8.40) and (8.63 ± 4.20), respectively. The highest percentages of void in and void out were observed in (Endofloss + Lentulo technique) group (23.08 ± 6.80) and (12.88 ± 3.40), respectively (Table 1 ). Table 1 The mean percentage and standard deviation of total void, void in, and void out in each study group separately Total void Obturation material Obturation technique Percentage average Standard deviation number ZOE Lentulo Reverse rotary Total 22.61 25.56 24.09 9.00 8.30 8.50 8 8 16 Endofloss Lentulo Reverse rotary Total 35.97 25.44 30.70 5.90 7.40 8.50 8 8 16 Total (ZOE + Endofloss) Lentulo Reverse rotary Total 29.29 25.50 27.39 10.10 7.60 9.00 16 16 32 Void in Obturation material Obturation technique Percentage average Standard deviation number ZOE Lentulo Reverse rotary Total 14.05 16.35 15.20 8.40 9.00 8.50 8 8 16 Endofloss Lentulo Reverse rotary Total 23.08 16.44 19.76 6.80 9.00 8.50 8 8 16 Total (ZOE + Endofloss) Lentulo Reverse rotary Total 18.56 16.40 17.48 8.73 8.73 8.66 16 16 32 Void out Obturation material Obturation technique Percentage average Standard deviation number ZOE Lentulo Reverse rotary Total 8.63 9.20 8.91 4.20 2.40 3.30 8 8 16 Endofloss Lentulo Reverse rotary Total 12.88 9.00 10.94 3.40 2.30 3.90 8 8 16 Total (ZOE + Endofloss) Lentulo Reverse rotary Total 10.75 9.10 9.93 4.60 2.30 3.70 16 16 32 Based on the analysis of variance (ANOVA), there was a statistically significant association between the amount of total void and the type of obturation material used (p = 0.023). In addition, no statistically significant association was found between the amount of total void and the obturation technique (p = 0.181). However, the interaction effect between the obturation material and technique revealed a statistically significant difference among the four groups in terms of total void (p = 0.021). There was no statistically significant relation between the amount of void in and void out separately and the type of material, the obturation technique, or the interaction between them (Table 2 ). Table 2 Association between obturation material, obturation technique, and their interaction with total void, void in, and void out (ANOVA: one-way and two-way). Total void Variable significance level (p value) Obturation material 0.023 Obturation technique 0.181 Interaction effect of Obturation material and technique 0.021 Void in Variable significance level (p value) Obturation material 0.134 Obturation technique 0.470 Interaction effect of Obturation material and technique 0.142 Void out Variable significance level (p value) Obturation material 0.105 Obturation technique 0.182 Interaction effect of Obturation material and technique 0.076 In the reverse rotary obturation technique, the type of obturation material (Endofloss or ZOE) had no effect on the amount of total void and void in. However, in the Lentulo obturation technique, the type of obturation material influenced the amount of total void and void in, with a higher total void and void in observed in the Endofloss group (Graph 1 and 2). However, in the reverse rotary obturation technique, the type of obturation material (Endofloss or ZOE) had a slight effect on the amount of void out with a higher void out in ZOE group. In addition, in the Lentulo obturation technique, the type of obturation material influenced the amount of void out, with a higher void out observed in the Endofloss group (Graph 3). Evaluation of filling volume The mean percentage of filling volume (in mm³) was highest in (ZOE + Lentulo technique) group (76.50 ± 9.10) and lowest in (Endofloss + Lentulo technique) group (64.02 ± 5.90). Moreover, the mean percentage of filling volume in teeth obturated with ZOE (75.47 ± 8.50) was overally higher than that in teeth obturated with Endofloss (69.22 ± 8.50). Additionally, the mean percentage of filling volume in teeth obturated using the reverse rotary technique (70.49 ± 7.60) was slightly higher than that using the Lentulo technique (70.26 ± 9.80). The overall mean percentage of filling volume in all obturated teeth was 72.38 ± 8.90 (Table 3 ). Table 3 Mean percentage and standard deviation of filling volume in each study group Obturation material Obturation technique Percentage average Standard deviation number ZOE Lentulo Reverse rotary Total 76.50 74.43 75.47 9.10 8.30 8.50 8 8 16 Endofloss Lentulo Reverse rotary Total 64.02 74.55 69.29 5.90 7.40 8.50 8 8 16 Total (ZOE + Endofloss) Lentulo Reverse rotary Total 70.26 70.49 72.38 9.80 7.60 8.90 16 16 32 Based on the analysis of variance (ANOVA), there was a statistically significant association between the amount of filling volume and the type of obturation material used (p = 0.034). In addition, no statistically significant association was found between the amount of filling volume and the obturation technique (p = 0.138). However, the interaction effect between the obturation material and technique revealed a statistically significant difference among the four groups in terms of filling volume (p = 0.031) (Table 4 ). Table 4 Results of the association between obturation material, obturation technique, and the interaction effect of material and technique with filling volume using ANOVA (one-way and two-way). Variable significance level (p value) Obturation material 0.034 Obturation technique 0.138 Interaction effect of Obturation material and technique 0.031 In the reverse rotary obturation technique, the type of obturation material (ZOE or Endofloss) had no significant effect on the filling volume of primary tooth root canals. However, in the Lentulo technique, ZOE showed a significantly higher filling volume compared to Endofloss (Graph 4). Discussion The presence of voids in the apical and middle thirds of the root may provide a pathway for leakage and bacterial accumulation, potentially leading to treatment failure ( 18 ). In the present study, regardless of the obturation material, the mean percentage of total void volume in the Lentulo technique group was higher than the reverse rotary technique group. Although the difference between these two techniques was not statistically significant, it may still hold clinical relevance. Regardless of the technique, the mean percentage of total void volume in samples obturated with ZOE was significantly lower than that in Endofloss samples. Moreover, the highest mean total void volume was observed in the (Endofloss + Lentulo) group and the lowest in the (ZOE + Lentulo) group and this difference was significant. Studies evaluating the quality of obturation with the Lentulo technique in term of voids have reported conflicting results. Peters et al. and Pandranki et al. (2005) found that the Lentulo technique resulted in fewer voids within the root canal ( 19 ). However, in contrast, studies by Vashista et al.(2015) ( 20 ) and the present investigation observed a higher void volume in the Lentulo technique compared to other methods. Jafarzadeh et al.(2019)similarly reported the highest void volume in the condensation method and the lowest in the Lentulo technique ( 18 ). These discrepancies may be attributed to differences in obturation techniques, irrigants used, and methodological variations between studies. To our knowledge, no previous study has compared the reverse rotary obturation technique with other techniques. Another potential explanation for the differences between the current study and others lies in the use of rotary instrumentation for canal preparation, which may have facilitated better access to the apical region ( 21 ). Nonetheless, challenges associated with the Lentulo spiral include the risk of instrument fracture and a tendency to extrude material beyond the apex. Additionally, improper adjustment of the rubber stop on the Lentulo may hinder accurate working length determination, increasing the risk of apical extrusion of obturating material ( 22 – 24 ). In the present study, regardless of material, the mean percentage of filling volume was slightly higher in the reverse rotary technique compared to the Lentulo technique. while no significant difference was reported between the Lentulo and reverse rotary techniques, though clinically relevant. Additionally, regardless of technique, the mean filling volume was significantly higher in samples obturated with ZOE compared to Endofloss. Furthermore, the highest mean filling volume was observed in the (ZOE + Lentulo) group (76.50%), while the lowest was in the (Endofloss + Lentulo) group (64.02%). Similarly, Bawazir et al.(2006) reported that 64% of primary teeth obturated with ZOE using the Lentulo technique were adequately filled ( 23 ). In the present study the interaction between obturation material and technique demonstrated a statistically significant difference among the four groups. Jafarzadeh et al. (2019) also reported acceptable obturation quality with the Lentulo technique, with 55% of canals adequately filled ( 18 ). This finding is consistent with results from Dandashi et al. (1993), Memarpour et al. (2013), and Nagaveni et al(2017) ( 22 , 25 , 26 ). A retrospective study in 2003 reported that nearly 70% of Endofloss-obturated teeth exhibited successful outcomes after 6–52 months of follow-up, with 83% success in flush and underfilled cases, and 58% in overfilled cases, suggesting Endofloss as a suitable alternative to traditional filling materials ( 27 ). In a study using micro-CT, Babashahi et al (2019). reported a higher filling volume percentage for ZOE (96.54%) compared to Metapex (87.97%) and nano-chitosan 3% (74.74%), although the differences were not statistically significant ( 28 ). Similarly, Priya Subramaniam and Kanupriya Gilhotra (2011) found no significant difference in clinical and radiographic success rate among Endofloss, ZOE, and Metapex ( 29 ). Differences in the study design (clinical vs. in vitro) and variables may explain discrepancies with the present findings. Inconsistent with our study, some reports suggest that Endofloss might achieve higher success rates than ZOE ( 30 ). A systematic review (2024) reported that ZOE was associated with higher failure rates than Endofloss, supporting Endofloss as a superior root-filling material for primary teeth ( 31 ). The review included clinical studies with 6- and 9-month follow-ups in children aged 3–9, whereas the present study was an in vitro study. Therefore, the reports of that study was based on the clinical and radiographic assessments in follow-up sessions rather than laboratory evaluation. Pandey et al. (1982) found the highest and lowest filling volume in canals obturated with Endofloss (88.87%) and ZOE (27.22%), respectively. They also reported better sealing ability with Endofloss than Metapex and ZOE ( 32 ). Contrary with the present study, Pandey et al. employed first and second primary molars (mandibular and maxillary). Additionally, the brands of ZOE material was different in their investigation. They also employed cone beam computed tomography for evaluating quality of root canal obturation, while micro-CT provides higher resolution, precise and non-destructive 3D imaging, enabling volumetric measurements and detailed analysis of void distribution and continuity following root canal obturation ( 33 ). Micro-CT is the only technique allowing assessment of size, type and location of voids in endodontic obturation without destroying or sectioning the samples which is critical to prevent contamination of obturation materials and ensure accurate evaluation. Additionally, micro-CT can detect voids as small as 7 microns, facilitating comparative evaluation of sealers and techniques to enhance obturation quality ( 34 ). Our study reported that the mean total void volume in the Endofloss + Lentulo group was 35.97%, and in the Endofloss + reverse rotary group was 25.44%, suggesting that obturation technique (reverse rotary vs. Lentulo) had a greater effect on total void percentage using Endofloss. However, Pandranki et al. found no significant difference in obturation length among different techniques using Endofloss ( 35 ). Our findings indicate that in the reverse rotary technique, obturation quality (in terms of total void and filling volume) was not significantly influenced by material employed; however, material choice significantly influenced on obturation quality in the Lentulo technique. Although several studies reported similar obturation quality between Lentulo and other techniques ( 36 , 37 ), to best our knowledge, none compared Lentulo with reverse rotary. The occurrence of voids following obturation can be attributed to several factors, including the anatomical complexity of the root canal, the quality of the preparation, the skill level of the operator, and the techniques employed during the obturation process ( 15 , 38 ). In this study, all biomechanical preparations were performed by a single operator using one rotary system to ensure reproducibility. Nonetheless, the material’s viscosity and density may influence the number and size of voids ( 39 , 40 ), potentially explaining the observed differences between materials. A notable strength of this study is evaluation of internal and external voids separately, enabling a more detailed analysis not addressed in other studies. Additionally, using micro-CT provided accurate 3D evaluation. Another strength was the obturation and assessment of all root canals of the tooth, while most studies assessed only one root. Conclusion In the base of findings of this study: Among the four groups evaluated in this study, the most effective obturation method was the use of zinc oxide eugenol (ZOE) with the Lentulo technique, while the least effective one was the use of Endofloss with the Lentulo technique. Superior root canal filling quality was seen in ZOE compared to Endofloss. The use of the reverse rotary file showed no considerable difference in the filling quality compared to the Lentulo technique. Therefore, the quality of obturation appears to be more dependent on the type of obturation material rather than the technique employed. However, the interaction between obturation material and technique plays a significant role in the quality of root canal obturation. Further in vitro and clinical studies with larger sample sizes and a variety of filling materials in primary teeth are needed in this area. Abbreviations ZOE Zinc oxide-eugenol Micro-CT Micro-computed tomography Declarations Availability of data and materials The dataset generated or analyzed during the current study are not publicly available due to the subject matter specialization, but are available from the corresponding author upon reasonable request and with permission of Qom University of Medical Sciences. Acknowledgements Authors would like to thank Clinical Research and development Unit, Shahid Beheshti Hospital, Qom University of Medical Sciences, Qom, Iran. Author contributions NEM and AM developed and supervised the work. FFT performed the data collection. MA performed the data analysis. AM and AS drafted the manuscript. NEM, AM and AS contributed to data interpretation. All authors reviewed and edited the manuscript. All authors read and approved the final manuscript. Ethics approval and consent to participate Ethical committee approval (Code No. IR.MUQ.REC.1402.208) was obtained from the Ethical Committee of Qom University of Medical Sciences, and the study was conducted in accordance with the Declaration of Helsinki. All subjects who donated their teeth for the current study and/or their legal guardians voluntarily agreed, and informed consent was obtained. Consent for publication Not applicable. Competing interests The authors declare no competing interests. Funding None (This research received no grant from any funding agency) References Nemezio MA, De Oliveira KM, Romualdo PC, Queiroz AM, Paula-e-Silva FW, Silva RA, et al. Association between fever and primary tooth eruption: a systematic review and meta-analysis. Int J Clin Pediatr Dent . 2017;10(3):293. Al-Shahrani N, Al-Amri A, Hegazi F, Al-Rowis K, Al-Madani A, Hassan KS. The prevalence of premature loss of primary teeth and its impact on malocclusion in the Eastern Province of Saudi Arabia. Acta Odontol Scand . 2015;73(7):544–9. Tafakhori Z, Shahrokhi E. An evaluation of the ability of the senior dental students of Rafsanjan University of Medical Sciences in detecting proximal caries in digital bitewing radiography in the academic year of 2019–2020. Sadra Med J . 2021;9(1):25–34. Al Dhubayb S, Al Sultan M, Al Sudairi S, Hakami F, Al Sweleh FS. Ability of dentists and students to detect caries by using the International Caries Detection and Assessment System. Clin Cosmet Investig Dent . 2021;13:379–87. Mehdipour A, Fateh R, Fuladvand F, Aghaali M, Keykha E, Hadilou M. Association between sleep pattern, salivary cariogenic bacteria and fungi populations, pH and buffering capacity in children: a comparative study. Dent Med Probl . 2024;61(2):217–24. Kazeminia M, Abdi A, Shohaimi S, Jalali R, Vaisi-Raygani A, Salari N, et al. Dental caries in primary and permanent teeth in children worldwide, 1995 to 2019: a systematic review and meta-analysis. Head Face Med . 2020;16:1–21. Warkhandkar A, Habib L, Warkhankar A. Effects of premature primary tooth loss on midline deviation and asymmetric molar relationship in the context of orthodontic treatment. Cureus . 2023;15(7):e12345. Sanusi SY, Al-Batayneh OB. Pulp therapy of primary dentition; its relevance despite insufficient histological evidence: a review. Iran Endod J . 2023;18(1):15. Mehdipour A, Heidari F, Nattaj MH, Torabi S, Aghaali M, Saleh A. Comparison of the sealability of four mineral trioxide aggregate materials in repairing of furcal perforation of the deciduous teeth: an in vitro study. Int J Clin Pediatr Dent . 2025;18(1):13. Hachem CE, Chedid JCA, Nehme W, Kaloustian MK, Ghosn N, Sahnouni H, et al. Physicochemical and antibacterial properties of conventional and two premixed root canal filling materials in primary teeth. J Funct Biomater . 2022;13(4):177. Elicherla SR, Bandi S, Saikiran KV, Nunna M, Sahiti PS, Nuvvula S. The clinical and radiographic success of Endoflas compared with other root canal obturating materials in primary teeth: a systematic review. Dent Res J (Isfahan) . 2022;19(1):72. Xavier SR, Pilownic KJ, Gastmann AH, Echeverria MS, Romano AR, Geraldo Pappen F. Bovine tooth discoloration induced by endodontic filling materials for primary teeth. Int J Dent . 2017;2017:7401962. Zargar N, Rezvani Y, Eftekhar L. Characteristics of root canal filling materials for primary teeth: a review of literature. J Dent Sch Shahid Beheshti Univ Med Sci . 2021;39:110–4. Almutairi M, Almutairi R, Almogbel S, Alfarhan A, Alharbi W, Alayoub RA, et al. Comparative evaluation of the quality of obturation between three obturation techniques in primary canines: an in vitro study. Cureus . 2024;16(7): e23456. Orhan AI, Tatli EC. Evaluation of root canal obturation quality in deciduous molars with different obturation materials: an in vitro micro‐computed tomography study. Biomed Res Int . 2021; 2021:6567161. Secilmis A, Dilber E, Gokmen F, Ozturk N, Telatar T. Effects of storage solutions on mineral contents of dentin. J Dent Sci . 2011;6(4):189–94. Zhang P, Yuan K, Jin Q, Zhao F, Huang Z. Presence of voids after three obturation techniques in band‐shaped isthmuses: a micro‐computed tomography study. BMC Oral Health . 2021;21(1):227. Jafarzadeh M, Saatchi M, Jafarnejadi P, Gooran M. Digital radiographic evaluation of the quality of different root canal obturation techniques in deciduous mandibular molars after preparation with rotary technique. J Dent (Tehran) . 2019;20(3):152. Peters CI, Koka R, Highsmith S, Peters OA. Calcium hydroxide dressings using different preparation and application modes: density and dissolution by simulated tissue pressure. Int Endod J . 2005;38(12):889–95. Vashista K, Sandhu M, Sachdev V. Comparative evaluation of obturating techniques in primary teeth: an in vivo study. Int J Clin Pediatr Dent . 2015;8(3):176. Buerklein S, Arias A. Effectiveness of root canal instrumentation for the treatment of apical periodontitis: a systematic review and meta‐analysis. Int Endod J. 2023;56:395–421. Memarpour M, Shahidi S, Meshki R. Comparison of different obturation techniques for primary molars by digital radiography. Pediatr Dent . 2013;35(3):236–40. Bawazir OA, Salama FS. Clinical evaluation of root canal obturation methods in primary teeth. Pediatr Dent . 2006;28(1):39–47. Huybrechts B, Bud M, Bergmans L, Lambrechts P, Jacobs R. Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images. Int Endod J . 2009;42(8):675–85. Dandashi MB, Nazif MM, Zullo T, Elliott MA, Schneider LG, Czonstkowsky M. An in vitro comparison of three endodontic techniques for primary incisors. Pediatr Dent . 1993;15:253–6. Nagaveni N, Yadav S, Poornima P, Reddy VS, Roshan N. Volumetric evaluation of different obturation techniques in primary teeth using spiral computed tomography. J Clin Pediatr Dent . 2017;41(1):27–31. Fuks A, Eidelman E, Pauker N. Root fillings with Endoflas in primary teeth: a retrospective study. J Clin Pediatr Dent . 2003;27(1):41–5. Babashahi E, Kartalaie MM, Basir L, Rakhshan V. Volumetric assessment of root canal obturation using 3% nano-chitosan versus zinc oxide eugenol (ZOE) and iodoform-calcium hydroxide (Metapex), in primary root canals shaped with rotary versus manual methods: a preliminary in-vitro spiral CT study. Front Dent . 2019;16(1):45. Subramaniam P, Gilhotra K. Endoflas, zinc oxide eugenol and Metapex as root canal filling materials in primary molars—a comparative clinical study. J Clin Pediatr Dent . 2011;35(4):365–70. Rewal N, Thakur AS, Sachdev V, Mahajan N. Comparison of Endoflas and zinc oxide eugenol as root canal filling materials in primary dentition. J Indian Soc Pedod Prev Dent . 2014;32(4):317–21. Awad R, Musa M, Elhoumed M, Liu F, Guo Q. Comparison of Endoflas and zinc oxide eugenol (ZOE) as root canal filling materials for pulpectomy in deciduous teeth: a systematic review and meta-analysis. Saudi Dent J . 2024. Pandey A, Avinash A, Pathivada L, Kumar B, Kapur D. Comparative volumetric analysis of three different obturating materials in primary molars under cone beam computed tomography: an in-vitro study. Minerva Dent Oral Sci . 2022;72(1):31–6. Ozturk G, Aydinbelge M, Gumus H. Comparison of various root canal filling materials and obturation techniques for primary teeth using microcomputed tomography. J Adv Oral Res . 2022;13(1):53–61. Loiacono R, Gómez A, Clavín MCG, Pinasco LB, Vázquez DJ, Gualtieri AF, et al. Micro-CT evaluation of the presence of voids in endodontic obturation. Acta Odontol Latinoam . 2024;37(1):3. Pandranki J, Vanga NR, Chandrabhatla SK. Zinc oxide eugenol and Endoflas pulpectomy in primary molars: 24-month clinical and radiographic evaluation. J Indian Soc Pedod Prev Dent . 2018;36(2):173–80. Shalan HM, Awad SM, Wahba AH, Mohamed HB. Comparative evaluation of different obturation techniques in primary molars pulpectomy: a clinical study. Acta Sci Dent Sci . 2022;6(3). Nagarathna C, Vishwanathan S, Krishnamurthy NH, Bhat PK. Primary molar pulpectomy using two different obturation techniques: a clinical study. Contemp Clin Dent . 2018;9(2):231–6. Keleş A, Alcin H, Kamalak A, Versiani M. Micro-CT evaluation of root filling quality in oval-shaped canals. Int Endod J . 2014;47(12):1177–84. Aragão AC, Pintor AVB, Marceliano-Alves M, Primo LG, Silva ASdS, Lopes RT, et al. Root canal obturation materials and filling techniques for primary teeth: in vitro evaluation in polymer-based prototyped incisors. Int J Paediatr Dent . 2020;30(3):381–9. Gandhi M, Tandon S, Vijay A, Kalia G, Rathore K. Clinical assessment of various obturating techniques for primary teeth: a comparative study. J Clin Diagn Res . 2017;11(7):ZC48. Graphs Graphs 1 to 4 are available in the Supplementary Files section Additional Declarations No competing interests reported. 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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-6710371","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":468205823,"identity":"f293ddc4-9791-496a-99a3-6f66828c6285","order_by":0,"name":"Niloufar Entezari Moghaddam","email":"","orcid":"","institution":"Qom University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Niloufar","middleName":"Entezari","lastName":"Moghaddam","suffix":""},{"id":468205824,"identity":"705a5082-439c-41af-9077-f6cb0b93736b","order_by":1,"name":"Farmehr Fadaei Tirani","email":"","orcid":"","institution":"Qom University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Farmehr","middleName":"Fadaei","lastName":"Tirani","suffix":""},{"id":468205825,"identity":"88d3c7d0-07cd-48ac-bbf8-5930c2952761","order_by":2,"name":"Mohammad Aghaali","email":"","orcid":"","institution":"Qom University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Aghaali","suffix":""},{"id":468205826,"identity":"e7bd3d0e-5104-4cb8-953b-300cbc103a33","order_by":3,"name":"Aida Mehdipour","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA70lEQVRIiWNgGAWjYFACHgaJBCjzAA+DDQODBIla0ojUgsQ+TFiLbnvvwRsPd9jImTcwPzzwpuZ8Yv/s5oMPGGpsonFpMTtzLtki8UyascwBNoODc47dTpxx51iyAcOxtNwGXFpu5JhJJLYdTpzBwGBwmIftdmIDSISx4TBuLfffwLSwfzjM8+9c4nyCWm7wwLTwGBzmbTuQuIGgljM5xmC/SDDwFByc25dsvPFGWrJBAj6/HD9jePMnMMQkGNg3f3jzzU523o3kgw8+1Njg1AIGjCBZ+QdgtiNYZQI+5XAtUGBPSPEoGAWjYBSMPAAAlxthi8X8PDoAAAAASUVORK5CYII=","orcid":"","institution":"Qom University of Medical Sciences","correspondingAuthor":true,"prefix":"","firstName":"Aida","middleName":"","lastName":"Mehdipour","suffix":""},{"id":468205827,"identity":"0c766f98-2f0d-4ec1-85f0-af4b03cdab49","order_by":4,"name":"Ali Saleh","email":"","orcid":"","institution":"Qom University of Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Ali","middleName":"","lastName":"Saleh","suffix":""}],"badges":[],"createdAt":"2025-05-20 18:53:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6710371/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6710371/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12903-025-07165-x","type":"published","date":"2025-11-16T15:57:23+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84190701,"identity":"4ea17feb-88f7-4cc3-90af-16c2ca2a3400","added_by":"auto","created_at":"2025-06-09 06:47:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":67584,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional slices along the longitudinal axis and axial sections at the coronal (A), middle (B), and apical (C) levels of a primary second molar root obturated with ZOE using the Lentulo obturation technique\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/d6c238f169629b0cdd839b3f.png"},{"id":84192531,"identity":"815cddae-1ce8-4435-a26a-a54405383f7d","added_by":"auto","created_at":"2025-06-09 07:03:01","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":172133,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional slices along the longitudinal axis and axial sections at the coronal (A), middle (B), and apical (C) levels of a primary second molar root obturated with ZOE using the reverse rotary obturation technique.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/a189031ba899f04904c8f7be.png"},{"id":84191599,"identity":"be3dd886-89d3-47d1-ae2e-df98243915f0","added_by":"auto","created_at":"2025-06-09 06:55:01","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":185015,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional slices along the longitudinal axis and axial sections at the coronal (A), middle (B), and apical (C) levels of a primary second molar root obturated with Endofloss using the reverse rotary obturation technique\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/bd6ea274abee73ebf3db725b.png"},{"id":84190704,"identity":"d9be8607-cab6-4ca6-98e5-838e9a5a15b5","added_by":"auto","created_at":"2025-06-09 06:47:01","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":122632,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional slices along the longitudinal axis and axial sections at the coronal (A), middle (B), and apical (C) levels of a primary second molar root obturated with Endofloss using the Lentulo obturation technique\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/9fb7e5b5212493f6eac0065e.png"},{"id":84190702,"identity":"efcb450c-bede-4c7c-99cd-c85806eef607","added_by":"auto","created_at":"2025-06-09 06:47:01","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":126769,"visible":true,"origin":"","legend":"\u003cp\u003eThe volume of void in and void out in the obturated samples (a–d)\u003c/p\u003e\n\u003cp\u003ea- The volume of void in and void out in the sample obturated with ZOE using the Lentulo obturation technique\u003c/p\u003e\n\u003cp\u003eb- The volume of void in and void out in the sample obturated with ZOE using the reverse rotary obturation technique\u003c/p\u003e\n\u003cp\u003ec- The volume of void in and void out in the sample obturated with Endofloss using the reverse rotary obturation technique\u003c/p\u003e\n\u003cp\u003ed- The volume of void in and void out in the sample obturated with Endofloss using the Lentulo obturation technique\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/5af2400c0f9b4f21e3559935.png"},{"id":96105245,"identity":"69fd4785-e913-48eb-bb2e-89642211db87","added_by":"auto","created_at":"2025-11-17 16:10:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1532540,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/646d4155-9675-421e-b208-ff452e4a33c5.pdf"},{"id":84191598,"identity":"fe7476d4-0716-4956-a058-16e0b7d02d5f","added_by":"auto","created_at":"2025-06-09 06:55:01","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":89171,"visible":true,"origin":"","legend":"","description":"","filename":"Graphs.docx","url":"https://assets-eu.researchsquare.com/files/rs-6710371/v1/53b90c4c620da73ac63b03ed.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eEruption of primary teeth is a crucial process in human development and plays a significant role in mastication, guiding the eruption of permanent succedaneous teeth, jaws growth, digestion, and speech development (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Loss of primary teeth due to caries is common. Dental caries is the most prevalent chronic disease worldwide and one of the most common diseases in children (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). This multifactorial disease is caused by bacteria and their acid production. Factors such as improper nutrition, unfavorable socioeconomic status, and poor oral hygiene increase the risk of primary tooth caries (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn children, this disease can lead to nutritional problems, growth impairment, speech difficulties, and compromised permanent teeth health (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Untreated primary teeth will be lost. Preserving posterior primary teeth until the eruption of their permanent successors is crucial, as their early loss can result in space deficiency, jaws and dental developmental issues, malnutrition, and aesthetic problems (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Pulpal therapy in primary teeth is divided into vital pulp therapy (for healthy pulp or reversible pulpitis) and non-vital pulp therapy (for irreversible pulpitis or pulp necrosis) (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). For primary teeth with irreversible pulpitis, chronic inflammation, or necrosis in the radicular pulp, pulpectomy is performed. The aim of this treatment is to preserve a tooth that would otherwise be extracted. The success of this procedure depends on microbial reduction, proper canal preparation, irrigation, and adequate sealing by the filling material (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAn ideal root canal filling material should possess sufficient adhesion, ease of application, biocompatibility with vital tissues and the permanent tooth germ, a resorption rate similar to that of primary root resorption, antibacterial properties, radio opacity, no tooth discoloration, and rapid resorption if extruded beyond the apex. To date, no single material fully meets all these criteria (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVarious materials, including zinc oxide-eugenol (ZOE) and combination pastes (Endofloss), are used for filling root canals of primary teeth. Although Zinc oxide-eugenol (ZOE) is an age-old material with a palliative effect, it has drawbacks such as a slow resorption rate and potential tissue irritation (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eCombination pastes (Endofloss) have a composition similar to calcium hydroxide and iodoform (Vitapex) and ZOE, exhibiting good antimicrobial properties. Their resorption rate is close to the rate of root resorption. However, they may cause tooth discoloration (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn addition to the material utilized, the quality of the root canal filling and achieving a homogenous and void-free obturation is a key factor in the success of pulpectomy in primary teeth (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVarious techniques, such as endodontic pressure syringes, lentulo spirals (manual and engine-driven), and rotary (reverse) instruments, have been developed for filling root canals of primary teeth (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough the reverse using of nickel-titanium rotary instruments for intracanal drug delivery in permanent teeth has been studied, limited research exists in this area for primary teeth.\u003c/p\u003e \u003cp\u003eVarious methods can be used to evaluate the quality of root canal filling, such as conventional periapical radiography, histological sectioning, scanning electron microscopy, stereomicroscopy, and micro-computed tomography (micro-CT). Micro-CT imaging is recognized as the most accurate non-invasive method for evaluating root canal treatment outcomes, providing three-dimensional assessment of root anatomy and differentiation of materials, canal structure, and potential voids (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTherefore, the aim of the present study is to compare the filling quality of primary teeth root canals using two instruments, lentulo spirals and reverse rotary files, with two materials, ZOE and Endofloss, utilizing micro-computed tomography.\u003c/p\u003e"},{"header":"Methods \u0026 Materials","content":"\u003cp\u003eThis experimental in vitro study was approved by Research Ethics Committee of Qom university of medical sciences and conducted on 32 extracted human primary second mandibular molar teeth (E) in Qom dental faculty, Qom, Iran in 2023\u0026ndash;2024. According to previous studies and using a two-mean comparison formula with α\u0026thinsp;=\u0026thinsp;0.05, β\u0026thinsp;=\u0026thinsp;0.2, σ₁ = 0.113, σ₂ = 0.04, \u0026micro;₁ = 0.1, and \u0026micro;₂ = 0.32, the sample size was calculated as 8 per group (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe inclusion criteria were a root length of 7 to 12 mm, the absence of any caries and internal or external root resorption in the tooth, the absence of fractures and cracks in the root and crown, and the absence of root canal calcifications. The exclusion criteria included a prolonged time interval between tooth extraction and the start of the preparation procedures and the presence of pulp stones in the pulp chamber. All criteria were confirmed by visual inspection and periapical radiography.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSamples preparation\u003c/h2\u003e \u003cp\u003eAfter removing excess tissue attached to the teeth by low-speed prophylactic brushing, all extracted teeth were immersed in a 0.5% thymol solution in distilled water for 48 hours for disinfection and then stored in distilled water for subsequent procedures (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eRoot canal preparation\u003c/h3\u003e\n\u003cp\u003eTo create access cavities in the teeth, the pulp chamber roof was completely removed using a high-speed diamond bur, and direct access to the orifices of all canals was established. After complete removal of the pulp tissue using a barbed broach and Hedstrom files (Mani, Japan), the canal length was assessed using a #10 K-file (Mani, Japan) until it reached the point of penetration, and the working length (WL) of the roots was determined to be 1 mm behind the apex.\u003c/p\u003e \u003cp\u003eSubsequently, all teeth were surrounded by red wax around the root apex (for easier identification in radiographs) and then mounted in acrylic resin.\u003c/p\u003e \u003cp\u003eA standard preparation technique was used for canal cleaning and shaping. After each filing, the canals were irrigated with a 1% normal saline solution.\u003c/p\u003e \u003cp\u003eFollowing complete root preparation and shaping, the teeth were randomly divided into 4 groups (n\u0026thinsp;=\u0026thinsp;8 in each group):\u003c/p\u003e \u003cp\u003e* Group 1: Teeth were obturated with ZOE (Kemdent Wiltshire, England) using a #25 Lentulo spiral (Medin, South Korea) attached to a low-speed handpiece. To prevent changes in the consistency of the ZOE material, the powder and liquid were mixed according to the manufacturer's instructions. To ensure accurate WL determination and ease of operation, half the length of the Lentulo spiral was cut (due to the shorter length of primary tooth canals), and the working length was then marked with a rubber stop. The Lentulo spiral was coated with the material and inserted into the canals, then moved along all canal walls at low speed. This process was repeated 3 to 4 times in each canal.\u003c/p\u003e \u003cp\u003e* Group 2: Teeth were obturated with Endofloss (Sanlor laboratories, USA) using a #25 Lentulo spiral filler attached to a low-speed handpiece. The mixing of the powder, liquid, and accelerator of Endofloss was performed according to the manufacturer's instructions.\u003c/p\u003e \u003cp\u003e* Group 3: Teeth were obturated with ZOE using an M3 Immature rotary file (UDG company, China) with reverse rotation. A #25 rotary file with a length of 16 mm and a rubber stop set at the canal length was used. The file, coated with the filling material, was inserted into the canal to the working length with a reverse rotation motion and moved along the canal walls. This process was repeated 3 to 4 times.\u003c/p\u003e \u003cp\u003e* Group 4: Teeth were obturated with Endofloss using an M3 Immature rotary file with reverse rotation.\u003c/p\u003e \u003cp\u003eTo prevent bias due to operator fatigue, only 5 teeth were prepared and then obturated in each session. All preparation and obturation procedures were performed by a single professional operator to avoid inter-operator variability, and one person was present monitoring throughout all stages to ensure consistency in the preparation and obturation procedures across all teeth and groups.\u003c/p\u003e \u003cp\u003eAfter completion of the root canal filling procedures, micro-CT imaging (Lotus-NDT, Behin Negareh, Iran) was used to evaluate the quality of the filling in the teeth of each group. All necessary information was recorded on a pre-set checklist.\u003c/p\u003e \u003cp\u003eThe percentage volume of the filling material in the canals and the percentage volume of voids (areas free of filling material) were determined for each canal using micro-CT imaging (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe data were entered into SPSS-26 software, and statistical analysis was performed at both descriptive and inferential levels. Descriptive statistics included using the means and standard deviations, along with relevant graphical representations. Inferential analysis involved the use of mean comparison tests and ANOVA to analyze the results at a significance level of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eEvaluation of total void, void in and void out:\u003c/h2\u003e \u003cp\u003eThe mean percentage of total void (void in +\u0026thinsp;void out) in mm\u0026sup3; was lowest in (ZOE\u0026thinsp;+\u0026thinsp;Lentulo technique) group (22.61\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00) and highest in (Endofloss\u0026thinsp;+\u0026thinsp;Lentulo technique) group (35.97\u0026thinsp;\u0026plusmn;\u0026thinsp;5.90). Moreover, the mean percentage of total void in teeth obturated with ZOE (24.09\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50) was overally lower than in teeth obturated with Endofloss (30.70\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50). Additionally, the mean percentage of total void using the reverse rotary obturation technique (25.50\u0026thinsp;\u0026plusmn;\u0026thinsp;7.60) was lower than that using the Lentulo technique (29.29\u0026thinsp;\u0026plusmn;\u0026thinsp;10.10). The overall mean percentage of total void across all obturated teeth was 27.39\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00. The mean percentages of void in and void out in (ZOE\u0026thinsp;+\u0026thinsp;Lentulo technique) group were the lowest (14.05\u0026thinsp;\u0026plusmn;\u0026thinsp;8.40) and (8.63\u0026thinsp;\u0026plusmn;\u0026thinsp;4.20), respectively. The highest percentages of void in and void out were observed in (Endofloss\u0026thinsp;+\u0026thinsp;Lentulo technique) group (23.08\u0026thinsp;\u0026plusmn;\u0026thinsp;6.80) and (12.88\u0026thinsp;\u0026plusmn;\u0026thinsp;3.40), respectively (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\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\u003eThe mean percentage and standard deviation of total void, void in, and void out in each study group separately\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=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTotal void\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage average\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003enumber\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZOE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.61\u003c/p\u003e \u003cp\u003e25.56\u003c/p\u003e \u003cp\u003e24.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.00\u003c/p\u003e \u003cp\u003e8.30\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndofloss\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.97\u003c/p\u003e \u003cp\u003e25.44\u003c/p\u003e \u003cp\u003e30.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.90\u003c/p\u003e \u003cp\u003e7.40\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal (ZOE\u0026thinsp;+\u0026thinsp;Endofloss)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.29\u003c/p\u003e \u003cp\u003e25.50\u003c/p\u003e \u003cp\u003e27.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.10\u003c/p\u003e \u003cp\u003e7.60\u003c/p\u003e \u003cp\u003e9.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVoid in\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage average\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003enumber\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZOE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.05\u003c/p\u003e \u003cp\u003e16.35\u003c/p\u003e \u003cp\u003e15.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.40\u003c/p\u003e \u003cp\u003e9.00\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndofloss\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.08\u003c/p\u003e \u003cp\u003e16.44\u003c/p\u003e \u003cp\u003e19.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.80\u003c/p\u003e \u003cp\u003e9.00\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal (ZOE\u0026thinsp;+\u0026thinsp;Endofloss)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.56\u003c/p\u003e \u003cp\u003e16.40\u003c/p\u003e \u003cp\u003e17.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.73\u003c/p\u003e \u003cp\u003e8.73\u003c/p\u003e \u003cp\u003e8.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVoid out\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage average\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003enumber\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZOE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.63\u003c/p\u003e \u003cp\u003e9.20\u003c/p\u003e \u003cp\u003e8.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.20\u003c/p\u003e \u003cp\u003e2.40\u003c/p\u003e \u003cp\u003e3.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndofloss\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.88\u003c/p\u003e \u003cp\u003e9.00\u003c/p\u003e \u003cp\u003e10.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.40\u003c/p\u003e \u003cp\u003e2.30\u003c/p\u003e \u003cp\u003e3.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal (ZOE\u0026thinsp;+\u0026thinsp;Endofloss)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.75\u003c/p\u003e \u003cp\u003e9.10\u003c/p\u003e \u003cp\u003e9.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.60\u003c/p\u003e \u003cp\u003e2.30\u003c/p\u003e \u003cp\u003e3.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e32\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\u003eBased on the analysis of variance (ANOVA), there was a statistically significant association between the amount of total void and the type of obturation material used (p\u0026thinsp;=\u0026thinsp;0.023). In addition, no statistically significant association was found between the amount of total void and the obturation technique (p\u0026thinsp;=\u0026thinsp;0.181). However, the interaction effect between the obturation material and technique revealed a statistically significant difference among the four groups in terms of total void (p\u0026thinsp;=\u0026thinsp;0.021). There was no statistically significant relation between the amount of void in and void out separately and the type of material, the obturation technique, or the interaction between them (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\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\u003eAssociation between obturation material, obturation technique, and their interaction with total void, void in, and void out (ANOVA: one-way and two-way).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eTotal void\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003esignificance level (p value)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.023\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.181\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInteraction effect of Obturation material and technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.021\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVoid in\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003esignificance level (p value)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.134\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.470\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInteraction effect of Obturation material and technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.142\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVoid out\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003esignificance level (p value)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.105\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.182\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInteraction effect of Obturation material and technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.076\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 reverse rotary obturation technique, the type of obturation material (Endofloss or ZOE) had no effect on the amount of total void and void in. However, in the Lentulo obturation technique, the type of obturation material influenced the amount of total void and void in, with a higher total void and void in observed in the Endofloss group (Graph 1 and 2). However, in the reverse rotary obturation technique, the type of obturation material (Endofloss or ZOE) had a slight effect on the amount of void out with a higher void out in ZOE group. In addition, in the Lentulo obturation technique, the type of obturation material influenced the amount of void out, with a higher void out observed in the Endofloss group (Graph 3).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEvaluation of filling volume\u003c/h3\u003e\n\u003cp\u003eThe mean percentage of filling volume (in mm\u0026sup3;) was highest in (ZOE\u0026thinsp;+\u0026thinsp;Lentulo technique) group (76.50\u0026thinsp;\u0026plusmn;\u0026thinsp;9.10) and lowest in (Endofloss\u0026thinsp;+\u0026thinsp;Lentulo technique) group (64.02\u0026thinsp;\u0026plusmn;\u0026thinsp;5.90). Moreover, the mean percentage of filling volume in teeth obturated with ZOE (75.47\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50) was overally higher than that in teeth obturated with Endofloss (69.22\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50). Additionally, the mean percentage of filling volume in teeth obturated using the reverse rotary technique (70.49\u0026thinsp;\u0026plusmn;\u0026thinsp;7.60) was slightly higher than that using the Lentulo technique (70.26\u0026thinsp;\u0026plusmn;\u0026thinsp;9.80). The overall mean percentage of filling volume in all obturated teeth was 72.38\u0026thinsp;\u0026plusmn;\u0026thinsp;8.90 (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean percentage and standard deviation of filling volume in each study group\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=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" 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\u003eObturation material\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePercentage average\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003enumber\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZOE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e76.50\u003c/p\u003e \u003cp\u003e74.43\u003c/p\u003e \u003cp\u003e75.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.10\u003c/p\u003e \u003cp\u003e8.30\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndofloss\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64.02\u003c/p\u003e \u003cp\u003e74.55\u003c/p\u003e \u003cp\u003e69.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.90\u003c/p\u003e \u003cp\u003e7.40\u003c/p\u003e \u003cp\u003e8.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal (ZOE\u0026thinsp;+\u0026thinsp;Endofloss)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLentulo\u003c/p\u003e \u003cp\u003eReverse rotary\u003c/p\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e70.26\u003c/p\u003e \u003cp\u003e70.49\u003c/p\u003e \u003cp\u003e72.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.80\u003c/p\u003e \u003cp\u003e7.60\u003c/p\u003e \u003cp\u003e8.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e16\u003c/p\u003e \u003cp\u003e32\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\u003eBased on the analysis of variance (ANOVA), there was a statistically significant association between the amount of filling volume and the type of obturation material used (p\u0026thinsp;=\u0026thinsp;0.034). In addition, no statistically significant association was found between the amount of filling volume and the obturation technique (p\u0026thinsp;=\u0026thinsp;0.138). However, the interaction effect between the obturation material and technique revealed a statistically significant difference among the four groups in terms of filling volume (p\u0026thinsp;=\u0026thinsp;0.031) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResults of the association between obturation material, obturation technique, and the interaction effect of material and technique with filling volume using ANOVA (one-way and two-way).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003esignificance level (p value)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation material\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.034\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObturation technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.138\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInteraction effect of Obturation material and technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.031\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 reverse rotary obturation technique, the type of obturation material (ZOE or Endofloss) had no significant effect on the filling volume of primary tooth root canals. However, in the Lentulo technique, ZOE showed a significantly higher filling volume compared to Endofloss (Graph 4).\u003c/p\u003e "},{"header":"Discussion","content":"\u003cp\u003eThe presence of voids in the apical and middle thirds of the root may provide a pathway for leakage and bacterial accumulation, potentially leading to treatment failure (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the present study, regardless of the obturation material, the mean percentage of total void volume in the Lentulo technique group was higher than the reverse rotary technique group. Although the difference between these two techniques was not statistically significant, it may still hold clinical relevance. Regardless of the technique, the mean percentage of total void volume in samples obturated with ZOE was significantly lower than that in Endofloss samples.\u003c/p\u003e \u003cp\u003eMoreover, the highest mean total void volume was observed in the (Endofloss\u0026thinsp;+\u0026thinsp;Lentulo) group and the lowest in the (ZOE\u0026thinsp;+\u0026thinsp;Lentulo) group and this difference was significant.\u003c/p\u003e \u003cp\u003eStudies evaluating the quality of obturation with the Lentulo technique in term of voids have reported conflicting results. Peters et al. and Pandranki et al. (2005) found that the Lentulo technique resulted in fewer voids within the root canal (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). However, in contrast, studies by Vashista et al.(2015) (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) and the present investigation observed a higher void volume in the Lentulo technique compared to other methods. Jafarzadeh et al.(2019)similarly reported the highest void volume in the condensation method and the lowest in the Lentulo technique (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). These discrepancies may be attributed to differences in obturation techniques, irrigants used, and methodological variations between studies. To our knowledge, no previous study has compared the reverse rotary obturation technique with other techniques.\u003c/p\u003e \u003cp\u003eAnother potential explanation for the differences between the current study and others lies in the use of rotary instrumentation for canal preparation, which may have facilitated better access to the apical region (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). Nonetheless, challenges associated with the Lentulo spiral include the risk of instrument fracture and a tendency to extrude material beyond the apex. Additionally, improper adjustment of the rubber stop on the Lentulo may hinder accurate working length determination, increasing the risk of apical extrusion of obturating material (\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the present study, regardless of material, the mean percentage of filling volume was slightly higher in the reverse rotary technique compared to the Lentulo technique. while no significant difference was reported between the Lentulo and reverse rotary techniques, though clinically relevant. Additionally, regardless of technique, the mean filling volume was significantly higher in samples obturated with ZOE compared to Endofloss. Furthermore, the highest mean filling volume was observed in the (ZOE\u0026thinsp;+\u0026thinsp;Lentulo) group (76.50%), while the lowest was in the (Endofloss\u0026thinsp;+\u0026thinsp;Lentulo) group (64.02%). Similarly, Bawazir et al.(2006) reported that 64% of primary teeth obturated with ZOE using the Lentulo technique were adequately filled (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). In the present study the interaction between obturation material and technique demonstrated a statistically significant difference among the four groups.\u003c/p\u003e \u003cp\u003eJafarzadeh et al. (2019) also reported acceptable obturation quality with the Lentulo technique, with 55% of canals adequately filled (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). This finding is consistent with results from Dandashi et al. (1993), Memarpour et al. (2013), and Nagaveni et al(2017) (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA retrospective study in 2003 reported that nearly 70% of Endofloss-obturated teeth exhibited successful outcomes after 6\u0026ndash;52 months of follow-up, with 83% success in flush and underfilled cases, and 58% in overfilled cases, suggesting Endofloss as a suitable alternative to traditional filling materials (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn a study using micro-CT, Babashahi et al (2019). reported a higher filling volume percentage for ZOE (96.54%) compared to Metapex (87.97%) and nano-chitosan 3% (74.74%), although the differences were not statistically significant (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSimilarly, Priya Subramaniam and Kanupriya Gilhotra (2011) found no significant difference in clinical and radiographic success rate among Endofloss, ZOE, and Metapex (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). Differences in the study design (clinical vs. in vitro) and variables may explain discrepancies with the present findings. Inconsistent with our study, some reports suggest that Endofloss might achieve higher success rates than ZOE (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). A systematic review (2024) reported that ZOE was associated with higher failure rates than Endofloss, supporting Endofloss as a superior root-filling material for primary teeth (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). The review included clinical studies with 6- and 9-month follow-ups in children aged 3\u0026ndash;9, whereas the present study was an in vitro study. Therefore, the reports of that study was based on the clinical and radiographic assessments in follow-up sessions rather than laboratory evaluation.\u003c/p\u003e \u003cp\u003ePandey et al. (1982) found the highest and lowest filling volume in canals obturated with Endofloss (88.87%) and ZOE (27.22%), respectively. They also reported better sealing ability with Endofloss than Metapex and ZOE (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e). Contrary with the present study, Pandey et al. employed first and second primary molars (mandibular and maxillary). Additionally, the brands of ZOE material was different in their investigation. They also employed cone beam computed tomography for evaluating quality of root canal obturation, while micro-CT provides higher resolution, precise and non-destructive 3D imaging, enabling volumetric measurements and detailed analysis of void distribution and continuity following root canal obturation (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMicro-CT is the only technique allowing assessment of size, type and location of voids in endodontic obturation without destroying or sectioning the samples which is critical to prevent contamination of obturation materials and ensure accurate evaluation. Additionally, micro-CT can detect voids as small as 7 microns, facilitating comparative evaluation of sealers and techniques to enhance obturation quality (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOur study reported that the mean total void volume in the Endofloss\u0026thinsp;+\u0026thinsp;Lentulo group was 35.97%, and in the Endofloss\u0026thinsp;+\u0026thinsp;reverse rotary group was 25.44%, suggesting that obturation technique (reverse rotary vs. Lentulo) had a greater effect on total void percentage using Endofloss. However, Pandranki et al. found no significant difference in obturation length among different techniques using Endofloss (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOur findings indicate that in the reverse rotary technique, obturation quality (in terms of total void and filling volume) was not significantly influenced by material employed; however, material choice significantly influenced on obturation quality in the Lentulo technique. Although several studies reported similar obturation quality between Lentulo and other techniques (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e), to best our knowledge, none compared Lentulo with reverse rotary.\u003c/p\u003e \u003cp\u003eThe occurrence of voids following obturation can be attributed to several factors, including the anatomical complexity of the root canal, the quality of the preparation, the skill level of the operator, and the techniques employed during the obturation process (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). In this study, all biomechanical preparations were performed by a single operator using one rotary system to ensure reproducibility. Nonetheless, the material\u0026rsquo;s viscosity and density may influence the number and size of voids (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e), potentially explaining the observed differences between materials.\u003c/p\u003e \u003cp\u003eA notable strength of this study is evaluation of internal and external voids separately, enabling a more detailed analysis not addressed in other studies. Additionally, using micro-CT provided accurate 3D evaluation. Another strength was the obturation and assessment of all root canals of the tooth, while most studies assessed only one root.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn the base of findings of this study:\u003c/p\u003e \u003cp\u003eAmong the four groups evaluated in this study, the most effective obturation method was the use of zinc oxide eugenol (ZOE) with the Lentulo technique, while the least effective one was the use of Endofloss with the Lentulo technique. Superior root canal filling quality was seen in ZOE compared to Endofloss. The use of the reverse rotary file showed no considerable difference in the filling quality compared to the Lentulo technique. Therefore, the quality of obturation appears to be more dependent on the type of obturation material rather than the technique employed. However, the interaction between obturation material and technique plays a significant role in the quality of root canal obturation.\u003c/p\u003e \u003cp\u003eFurther in vitro and clinical studies with larger sample sizes and a variety of filling materials in primary teeth are needed in this area.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eZOE \u0026nbsp;Zinc oxide-eugenol\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMicro-CT \u0026nbsp;Micro-computed tomography\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset generated or analyzed during the current study are not publicly available due to the subject matter specialization, but are available from the corresponding author upon reasonable request and with permission of Qom University of Medical Sciences.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors would like to thank Clinical Research and development Unit, Shahid Beheshti Hospital, Qom University of Medical Sciences, Qom, Iran.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNEM and AM developed and supervised the work. FFT performed the data collection. MA performed the data analysis. AM and AS drafted the manuscript. NEM, AM and AS contributed to data interpretation. All authors reviewed and edited the manuscript. All authors read and approved the final manuscript.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical committee approval (Code No. IR.MUQ.REC.1402.208)\u0026nbsp;was obtained from the Ethical Committee of\u0026nbsp;Qom University of Medical Sciences, and the study was conducted in accordance with the Declaration of Helsinki. All subjects who donated their teeth for the current study and/or their legal guardians voluntarily agreed, and informed consent was obtained.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone (This research received no grant from any funding agency)\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNemezio MA, De Oliveira KM, Romualdo PC, Queiroz AM, Paula-e-Silva FW, Silva RA, et al. Association between fever and primary tooth eruption: a systematic review and meta-analysis. \u003cem\u003eInt J Clin Pediatr Dent\u003c/em\u003e. 2017;10(3):293.\u003c/li\u003e\n\u003cli\u003eAl-Shahrani N, Al-Amri A, Hegazi F, Al-Rowis K, Al-Madani A, Hassan KS. The prevalence of premature loss of primary teeth and its impact on malocclusion in the Eastern Province of Saudi Arabia. \u003cem\u003eActa Odontol Scand\u003c/em\u003e. 2015;73(7):544\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eTafakhori Z, Shahrokhi E. An evaluation of the ability of the senior dental students of Rafsanjan University of Medical Sciences in detecting proximal caries in digital bitewing radiography in the academic year of 2019\u0026ndash;2020. \u003cem\u003eSadra Med J\u003c/em\u003e. 2021;9(1):25\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eAl Dhubayb S, Al Sultan M, Al Sudairi S, Hakami F, Al Sweleh FS. Ability of dentists and students to detect caries by using the International Caries Detection and Assessment System. \u003cem\u003eClin Cosmet Investig Dent\u003c/em\u003e. 2021;13:379\u0026ndash;87.\u003c/li\u003e\n\u003cli\u003eMehdipour A, Fateh R, Fuladvand F, Aghaali M, Keykha E, Hadilou M. Association between sleep pattern, salivary cariogenic bacteria and fungi populations, pH and buffering capacity in children: a comparative study. \u003cem\u003eDent Med Probl\u003c/em\u003e. 2024;61(2):217\u0026ndash;24.\u003c/li\u003e\n\u003cli\u003eKazeminia M, Abdi A, Shohaimi S, Jalali R, Vaisi-Raygani A, Salari N, et al. Dental caries in primary and permanent teeth in children worldwide, 1995 to 2019: a systematic review and meta-analysis. \u003cem\u003eHead Face Med\u003c/em\u003e. 2020;16:1\u0026ndash;21.\u003c/li\u003e\n\u003cli\u003eWarkhandkar A, Habib L, Warkhankar A. Effects of premature primary tooth loss on midline deviation and asymmetric molar relationship in the context of orthodontic treatment. \u003cem\u003eCureus\u003c/em\u003e. 2023;15(7):e12345.\u003c/li\u003e\n\u003cli\u003eSanusi SY, Al-Batayneh OB. Pulp therapy of primary dentition; its relevance despite insufficient histological evidence: a review. \u003cem\u003eIran Endod J\u003c/em\u003e. 2023;18(1):15.\u003c/li\u003e\n\u003cli\u003eMehdipour A, Heidari F, Nattaj MH, Torabi S, Aghaali M, Saleh A. Comparison of the sealability of four mineral trioxide aggregate materials in repairing of furcal perforation of the deciduous teeth: an in vitro study. \u003cem\u003eInt J Clin Pediatr Dent\u003c/em\u003e. 2025;18(1):13.\u003c/li\u003e\n\u003cli\u003eHachem CE, Chedid JCA, Nehme W, Kaloustian MK, Ghosn N, Sahnouni H, et al. Physicochemical and antibacterial properties of conventional and two premixed root canal filling materials in primary teeth. \u003cem\u003eJ Funct Biomater\u003c/em\u003e. 2022;13(4):177.\u003c/li\u003e\n\u003cli\u003eElicherla SR, Bandi S, Saikiran KV, Nunna M, Sahiti PS, Nuvvula S. The clinical and radiographic success of Endoflas compared with other root canal obturating materials in primary teeth: a systematic review. \u003cem\u003eDent Res J (Isfahan)\u003c/em\u003e. 2022;19(1):72.\u003c/li\u003e\n\u003cli\u003eXavier SR, Pilownic KJ, Gastmann AH, Echeverria MS, Romano AR, Geraldo Pappen F. Bovine tooth discoloration induced by endodontic filling materials for primary teeth. \u003cem\u003eInt J Dent\u003c/em\u003e. 2017;2017:7401962.\u003c/li\u003e\n\u003cli\u003eZargar N, Rezvani Y, Eftekhar L. Characteristics of root canal filling materials for primary teeth: a review of literature. \u003cem\u003eJ Dent Sch Shahid Beheshti Univ Med Sci\u003c/em\u003e. 2021;39:110\u0026ndash;4.\u003c/li\u003e\n\u003cli\u003eAlmutairi M, Almutairi R, Almogbel S, Alfarhan A, Alharbi W, Alayoub RA, et al. Comparative evaluation of the quality of obturation between three obturation techniques in primary canines: an in vitro study. \u003cem\u003eCureus\u003c/em\u003e. 2024;16(7): e23456.\u003c/li\u003e\n\u003cli\u003eOrhan AI, Tatli EC. Evaluation of root canal obturation quality in deciduous molars with different obturation materials: an in vitro micro‐computed tomography study. \u003cem\u003eBiomed Res Int\u003c/em\u003e. 2021; 2021:6567161.\u003c/li\u003e\n\u003cli\u003eSecilmis A, Dilber E, Gokmen F, Ozturk N, Telatar T. Effects of storage solutions on mineral contents of dentin. \u003cem\u003eJ Dent Sci\u003c/em\u003e. 2011;6(4):189\u0026ndash;94.\u003c/li\u003e\n\u003cli\u003eZhang P, Yuan K, Jin Q, Zhao F, Huang Z. Presence of voids after three obturation techniques in band‐shaped isthmuses: a micro‐computed tomography study. \u003cem\u003eBMC Oral Health\u003c/em\u003e. 2021;21(1):227.\u003c/li\u003e\n\u003cli\u003eJafarzadeh M, Saatchi M, Jafarnejadi P, Gooran M. Digital radiographic evaluation of the quality of different root canal obturation techniques in deciduous mandibular molars after preparation with rotary technique. \u003cem\u003eJ Dent (Tehran)\u003c/em\u003e. 2019;20(3):152.\u003c/li\u003e\n\u003cli\u003ePeters CI, Koka R, Highsmith S, Peters OA. Calcium hydroxide dressings using different preparation and application modes: density and dissolution by simulated tissue pressure. \u003cem\u003eInt Endod J\u003c/em\u003e. 2005;38(12):889\u0026ndash;95.\u003c/li\u003e\n\u003cli\u003eVashista K, Sandhu M, Sachdev V. Comparative evaluation of obturating techniques in primary teeth: an in vivo study. \u003cem\u003eInt J Clin Pediatr Dent\u003c/em\u003e. 2015;8(3):176.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eBuerklein S, Arias A. Effectiveness of root canal instrumentation for the treatment of apical periodontitis: a systematic review and meta‐analysis. Int Endod J. 2023;56:395\u0026ndash;421.\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eMemarpour M, Shahidi S, Meshki R. Comparison of different obturation techniques for primary molars by digital radiography. \u003cem\u003ePediatr Dent\u003c/em\u003e. 2013;35(3):236\u0026ndash;40.\u003c/li\u003e\n\u003cli\u003eBawazir OA, Salama FS. Clinical evaluation of root canal obturation methods in primary teeth. \u003cem\u003ePediatr Dent\u003c/em\u003e. 2006;28(1):39\u0026ndash;47.\u003c/li\u003e\n\u003cli\u003eHuybrechts B, Bud M, Bergmans L, Lambrechts P, Jacobs R. Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images. \u003cem\u003eInt Endod J\u003c/em\u003e. 2009;42(8):675\u0026ndash;85.\u003c/li\u003e\n\u003cli\u003eDandashi MB, Nazif MM, Zullo T, Elliott MA, Schneider LG, Czonstkowsky M. An in vitro comparison of three endodontic techniques for primary incisors. \u003cem\u003ePediatr Dent\u003c/em\u003e. 1993;15:253\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eNagaveni N, Yadav S, Poornima P, Reddy VS, Roshan N. Volumetric evaluation of different obturation techniques in primary teeth using spiral computed tomography. \u003cem\u003eJ Clin Pediatr Dent\u003c/em\u003e. 2017;41(1):27\u0026ndash;31.\u003c/li\u003e\n\u003cli\u003eFuks A, Eidelman E, Pauker N. Root fillings with Endoflas in primary teeth: a retrospective study. \u003cem\u003eJ Clin Pediatr Dent\u003c/em\u003e. 2003;27(1):41\u0026ndash;5.\u003c/li\u003e\n\u003cli\u003eBabashahi E, Kartalaie MM, Basir L, Rakhshan V. Volumetric assessment of root canal obturation using 3% nano-chitosan versus zinc oxide eugenol (ZOE) and iodoform-calcium hydroxide (Metapex), in primary root canals shaped with rotary versus manual methods: a preliminary in-vitro spiral CT study. \u003cem\u003eFront Dent\u003c/em\u003e. 2019;16(1):45.\u003c/li\u003e\n\u003cli\u003eSubramaniam P, Gilhotra K. Endoflas, zinc oxide eugenol and Metapex as root canal filling materials in primary molars\u0026mdash;a comparative clinical study. \u003cem\u003eJ Clin Pediatr Dent\u003c/em\u003e. 2011;35(4):365\u0026ndash;70.\u003c/li\u003e\n\u003cli\u003eRewal N, Thakur AS, Sachdev V, Mahajan N. Comparison of Endoflas and zinc oxide eugenol as root canal filling materials in primary dentition. \u003cem\u003eJ Indian Soc Pedod Prev Dent\u003c/em\u003e. 2014;32(4):317\u0026ndash;21.\u003c/li\u003e\n\u003cli\u003eAwad R, Musa M, Elhoumed M, Liu F, Guo Q. Comparison of Endoflas and zinc oxide eugenol (ZOE) as root canal filling materials for pulpectomy in deciduous teeth: a systematic review and meta-analysis. \u003cem\u003eSaudi Dent J\u003c/em\u003e. 2024.\u003c/li\u003e\n\u003cli\u003ePandey A, Avinash A, Pathivada L, Kumar B, Kapur D. Comparative volumetric analysis of three different obturating materials in primary molars under cone beam computed tomography: an in-vitro study. \u003cem\u003eMinerva Dent Oral Sci\u003c/em\u003e. 2022;72(1):31\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eOzturk G, Aydinbelge M, Gumus H. Comparison of various root canal filling materials and obturation techniques for primary teeth using microcomputed tomography. \u003cem\u003eJ Adv Oral Res\u003c/em\u003e. 2022;13(1):53\u0026ndash;61.\u003c/li\u003e\n\u003cli\u003eLoiacono R, G\u0026oacute;mez A, Clav\u0026iacute;n MCG, Pinasco LB, V\u0026aacute;zquez DJ, Gualtieri AF, et al. Micro-CT evaluation of the presence of voids in endodontic obturation. \u003cem\u003eActa Odontol Latinoam\u003c/em\u003e. 2024;37(1):3.\u003c/li\u003e\n\u003cli\u003ePandranki J, Vanga NR, Chandrabhatla SK. Zinc oxide eugenol and Endoflas pulpectomy in primary molars: 24-month clinical and radiographic evaluation. \u003cem\u003eJ Indian Soc Pedod Prev Dent\u003c/em\u003e. 2018;36(2):173\u0026ndash;80.\u003c/li\u003e\n\u003cli\u003eShalan HM, Awad SM, Wahba AH, Mohamed HB. Comparative evaluation of different obturation techniques in primary molars pulpectomy: a clinical study. \u003cem\u003eActa Sci Dent Sci\u003c/em\u003e. 2022;6(3).\u003c/li\u003e\n\u003cli\u003eNagarathna C, Vishwanathan S, Krishnamurthy NH, Bhat PK. Primary molar pulpectomy using two different obturation techniques: a clinical study. \u003cem\u003eContemp Clin Dent\u003c/em\u003e. 2018;9(2):231\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eKeleş A, Alcin H, Kamalak A, Versiani M. Micro-CT evaluation of root filling quality in oval-shaped canals. \u003cem\u003eInt Endod J\u003c/em\u003e. 2014;47(12):1177\u0026ndash;84.\u003c/li\u003e\n\u003cli\u003eArag\u0026atilde;o AC, Pintor AVB, Marceliano-Alves M, Primo LG, Silva ASdS, Lopes RT, et al. Root canal obturation materials and filling techniques for primary teeth: in vitro evaluation in polymer-based prototyped incisors. \u003cem\u003eInt J Paediatr Dent\u003c/em\u003e. 2020;30(3):381\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eGandhi M, Tandon S, Vijay A, Kalia G, Rathore K. Clinical assessment of various obturating techniques for primary teeth: a comparative study. \u003cem\u003eJ Clin Diagn Res\u003c/em\u003e. 2017;11(7):ZC48.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Graphs","content":"\u003cp\u003eGraphs 1 to 4 are available in the Supplementary Files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Root Canal Therapy, Deciduous teeth, Endofloss, Zinc Oxide-Eugenol, Micro-Computed Tomography","lastPublishedDoi":"10.21203/rs.3.rs-6710371/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6710371/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePrimary teeth are necessary for mastication, speech, and guiding the eruption of permanent teeth. Dental caries often requires pulpectomy treatment to preserve these teeth. The success of pulpectomy depends on root canal obturation quality. This study aimed to compare the filling quality of zinc oxide-eugenol (ZOE) and Endofloss using lentulo and reverse rotary techniques, assessed by micro-computed tomography.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eAn in vitro study was conducted on 32 extracted human primary mandibular second molars. Teeth were randomly divided into four groups (n\u0026thinsp;=\u0026thinsp;8) based on obturation material (ZOE or Endofloss) and technique (lentulo spiral or reverse rotary file). After standard canal preparation, obturation was performed. Micro-computed tomography assessed the quality of obturation by measuring the percentage of void and filling volume. Statistical analysis was performed using ANOVA test (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe lowest total void percentage was observed in the (ZOE\u0026thinsp;+\u0026thinsp;Lentulo) group (22.61\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00), and the highest in the (Endofloss|+Lentulo) group (35.97\u0026thinsp;\u0026plusmn;\u0026thinsp;5.90). ZOE obturation resulted in lower voids (24.09\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50) compared to Endofloss (30.70\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50). The reverse rotary technique showed non significant lower voids (25.50\u0026thinsp;\u0026plusmn;\u0026thinsp;7.60) than Lentulo (29.29\u0026thinsp;\u0026plusmn;\u0026thinsp;10.10) (p\u0026thinsp;=\u0026thinsp;0.181). A significant interaction effect was observed between material and technique in term of total voids (p\u0026thinsp;=\u0026thinsp;0.021). (ZOE\u0026thinsp;+\u0026thinsp;Lentulo) group showed the highest filling volume (76.50\u0026thinsp;\u0026plusmn;\u0026thinsp;9.10), while(Endofloss\u0026thinsp;+\u0026thinsp;Lentulo) had the lowest (64.02\u0026thinsp;\u0026plusmn;\u0026thinsp;5.90). ZOE yielded higher filling volume (75.47\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50) compared to Endofloss (69.22\u0026thinsp;\u0026plusmn;\u0026thinsp;8.50), with a significant material effect (p\u0026thinsp;=\u0026thinsp;0.034), but no significant effect of technique (p\u0026thinsp;=\u0026thinsp;0.138).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eZOE\u0026thinsp;+\u0026thinsp;Lentulo technique provided the most root canal obturation quality, while Endofloss\u0026thinsp;+\u0026thinsp;Lentulo showed the least quality. The root canal filling quality was more influenced by the obturation material than the technique used.\u003c/p\u003e","manuscriptTitle":"In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-09 06:46:57","doi":"10.21203/rs.3.rs-6710371/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-07T09:41:28+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-04T21:09:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-02T07:26:48+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-20T23:03:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"36924498915628286946620281944931187614","date":"2025-06-09T05:49:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"277222239900012924985873836305178447802","date":"2025-06-08T08:59:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155366449935035604801736690629216983386","date":"2025-06-08T04:56:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"270202005401316613273731604121132209754","date":"2025-06-06T19:19:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"301095591868458702853171543228181175753","date":"2025-06-05T17:11:34+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-05T11:44:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-05T11:37:40+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-28T07:36:18+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-27T18:06:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-05-27T18:05:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0dd99fe8-b025-4f2c-babb-c4aa6019060f","owner":[],"postedDate":"June 9th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T16:06:13+00:00","versionOfRecord":{"articleIdentity":"rs-6710371","link":"https://doi.org/10.1186/s12903-025-07165-x","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2025-11-16 15:57:23","publishedOnDateReadable":"November 16th, 2025"},"versionCreatedAt":"2025-06-09 06:46:57","video":"","vorDoi":"10.1186/s12903-025-07165-x","vorDoiUrl":"https://doi.org/10.1186/s12903-025-07165-x","workflowStages":[]},"version":"v1","identity":"rs-6710371","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6710371","identity":"rs-6710371","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}