The effect of Chlorohexidine, Er:YAG Laser and Diode Laser 980 nm as Dental Cavity Disinfectants on Dentine Morphology and Microleakage of Composite Restoration: An In Vitro Study

The effect of Chlorohexidine, Er:YAG Laser and Diode Laser 980 nm as Dental Cavity Disinfectants on Dentine Morphology and Microleakage of Composite Restoration: An In Vitro Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article The effect of Chlorohexidine, Er:YAG Laser and Diode Laser 980 nm as Dental Cavity Disinfectants on Dentine Morphology and Microleakage of Composite Restoration: An In Vitro Study menna khafagi, Mostafa Gheith, Haythem Moharrum, Mohammed Ahmed, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7345490/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 Jan, 2026 Read the published version in BDJ Open → Version 1 posted 4 You are reading this latest preprint version Abstract Introduction Residual microorganisms may remain even after thorough mechanical cavity preparation, leading to secondary caries. Additionally, the smear layer generated during this process can impair the adhesion between composite resin and dentine and limit the penetration of disinfectants into dentinal tubules. This study aimed to compare the effects of 2% chlorhexidine (CHX), 980 nm diode laser, and Er:YAG laser as cavity disinfectants on dentine morphology, mineral content, and microleakage of composite restorations. Materials and Methods Forty extracted sound human primary molars were randomly assigned to four groups (n = 10): Group I (negative control, no disinfection), Group II (2% CHX application), Group III (980 nm diode laser, 1 W, continuous wave), and Group IV (Er:YAG laser, 1.2 W). Dentine morphology and restoration microleakage were examined via Scanning Electron Microscopy: (SEM), while mineral content was evaluated using Energy-Dispersive X-ray Spectroscopy (EDX). Results SEM analysis showed that CHX (Group II) left smear layer residues with narrowed tubules, while the diode laser (Group III) partially removed the smear layer. Er:YAG laser (Group IV) resulted in complete smear layer removal, wider tubules. EDX revealed significantly higher mineral content in Group IV compared to Groups II and group III (p < 0.001), with no significant difference between Groups II and III. Microleakage was highest in the control group and lowest in the Er:YAG group (p < 0.001). Conclusion The Er:YAG laser showed superior outcomes in improving dentine morphology, increasing mineral content, and minimizing microleakage, making it the most effective disinfectant tested. Health sciences/Health care/Dentistry Health sciences/Health care/Dentistry/Paediatric dentistry Erbium:YAG laser diode laser chlorhexidine dentin morphology mineral content microleakage cavity disinfection composite restoration Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Introduction Dental caries is a highly prevalent condition globally that represents a multifactorial disease arising from the complex interplay between cariogenic bacteria, dietary sugars, and host-related factors. These microorganisms metabolize dietary sugars, generating acids that gradually demineralize the tooth's hard tissues, ultimately resulting in tooth decay [ 1 ] Cervical caries is a common form of tooth decay, often resulting from poor oral hygiene, and a highly cariogenic diet. Residual microorganisms can persist even after thorough mechanical preparation, particularly in cases of incomplete caries removal. [ 2 ] These bacteria may penetrate the restoration-tooth interface, promoting microleakage and increasing the risk of secondary or recurrent caries⁽¹¹⁾. To minimize this risk, disinfecting the dentin surface is recommended following cavity preparation and before placing any restorative material [ 3 ]. Additionally, a smear layer formed during cavity preparation can be a barrier preventing adequate bonding between composite resin restoration and dentine and disinfectants from effectively penetrating the dentinal tubules [ 2 ]. Dentin, a mineralized tissue, is composed of both organic and inorganic components. Its inorganic portion mainly consists of hydroxyapatite crystals containing calcium (Ca) and phosphorus (P). The typical calcium-to-phosphorus (Ca/P) ratio in dentin hydroxyapatite is approximately 1.67, which reflects a stable and consistent mineral composition. However, this ratio can vary depending on crystal type, calcium availability, anatomical location, and measurement method [ 4 ] Chemical agents used during dental procedures may alter the Ca/P ratio, leading to changes in the structural and chemical integrity of dentin, including its permeability and solubility which can consequently disrupt the balance between dentin’s organic and inorganic components and negatively impact its physical properties such as micro-hardness and roughness. [ 5 ] Furthermore, these chemical agents can lead to a reduction in mineral content that may compromise the mechanical strength and have a direct impact on bonding between dentine and restorative material which can affect the long-term durability of the restoration [ 6 ] So, Microleakage, defined as the undetectable seepage of fluids, bacteria, or ions between the tooth structure and restoration, is a leading cause of clinical failure [ 7 ]. It may lead to tooth discoloration, postoperative sensitivity, recurrent decay, and pulpal complications. Therefore, optimizing disinfection protocols and improving adhesive bonding are crucial for reducing bacterial contamination, enhancing marginal integrity, and ensuring the longevity of composite restorations [ 8 ] Chlorhexidine (CHX) is widely regarded as the gold standard for cavity disinfection due to its strong antimicrobial properties and its ability to bind to bacterial amino acids. Studies have shown that concentrations of up to 10% are considered safe for use on living tissues [ 9 ]. However, Chlorhexidine (CHX) lacks the ability to dissolve tissue and effectively remove the smear layer. As a result, the residual smear layer can act as a barrier, reducing the contact time between the irrigant and the dentin [ 10 ] In the recent years, lasers have gained popularity in dentistry due to their broad range of applications; one of these applications is dental cavity disinfection. In addition to effectively penetrating and eliminating bacteria, they can also seal dentinal tubules, thereby preventing potential pathways for bacterial reinfection. Lasers have the ability of removal of smear layer, consequently increasing the bonding strength between restorative material and dentine. [ 11 ] Among the lasers that are widely used as cavity disinfectants; Diode 980nm and Erbium YAG 2840nm. "Diode lasers offer the advantage of effectively removing the smear layer and inducing melting of the dentin surface with partial to complete obliteration of dentinal tubules [ 2 ] Low-energy Er:YAG laser treatment modifies the dentin surface by efficiently eliminating debris and revealing open dentinal tubules. Research indicates that the heat produced by the Er:YAG laser can neutralize free radicals and alter the dentin, resulting in a surface more favorable for bonding [ 12 ] According to our knowledge, there is no study compared the effect of chlorohexidine, diode laser 980 nm and Er:YAG laser when used for dentine disinfection, on dentine morphology and mineral content. Therefore, this study was conducted to assess the morphological changes and mineral content of dentine using a scanning electron microscope and EDX and to evaluate microleakage of composite resin restoration using SEM. Materials and Methods 2.1. Study Design This in vitro experimental study adhered to the CRIS Guidelines (Checklist for Reporting In-vitro Studies) published in 2014 to ensure methodological transparency and research quality [ 13 ]. A total of 40 freshly extracted human primary molars were used. To minimize structural variability, extractions were performed at or near the natural exfoliation period. 2.2. Ethical Considerations The authors bear full accountability for all aspects of the research, guaranteeing that any issues related to the accuracy or integrity of any component are rigorously investigated and appropriately resolved. All procedures were executed in full compliance with the ethical principles set forth in the Declaration of Helsinki. Informed consent was secured from all participants prior to their involvement in the study. The experimental protocol was reviewed and approved by the Medical Research Ethics Committee of the National Research Centre (approval no1234052022.). 0n 7/4/2022 2.3. Sample Size Calculation Sample size was determined based on a previous study by Jamel and Taher (2024), which evaluated the antibacterial efficacy of a 940 nm diode laser on Streptococcus mutans and other cariogenic bacteria. Their study reported mean ± SD of CFU as 34 ± 5.8 in Group I and 25 ± 3.6 in Group II, yielding an effect size of 1.86. Using a power of 0.9 and a significance level (α) of 0.05, the minimum required sample size was calculated to be 8 per group. To account for a potential 20% dropout, this was increased to 10 per group. The calculation was conducted using a t-test in G*Power software (version 3.1.4.9) [ 14 ] 2.4. Randomization and Allocation All 40 extracted teeth were labeled numerically (1–40) and stored in a sterile, sealed, opaque container. Random allocation into four equal groups (n = 10) was carried out using a computer-generated random sequence from www.random.org on November 12, 2024, applying a 1:1 allocation ratio. 2.5. Blinding A double-blind design was adopted. Both the SEM and EDX examiners and the statistician performing the data evaluation were blinded to the group assignments. 2.6. Specimen Selection and Preparation 2.6.1. Inclusion and Exclusion Criteria Inclusion criteria : Sound freshly extracted primary molars with at least 50% of root structure intact. Exclusion criteria : Teeth with cracks, restorations, deep caries, pulpal involvement, structural anomalies, or prior dental treatment were excluded. 2.6.2. Collection and Storage Teeth were collected from the outpatient pediatric dentistry clinic of the NRC. An informed parental consent was obtained before extraction. Parents were briefed about the study involving their child’s extracted teeth. Following extraction, the teeth were rinsed with tap water, residual soft tissues were carefully removed using a scalpel, and the crowns were gently cleaned with a soft-bristled brush (Sulcus, Oral-B, Mexico). Prior to analysis, the specimens were stored in deionized water at 4°C [ 15 ]. The structural integrity of all samples was first assessed through visual inspection, followed by examination under a stereoscope (Olympus Optical Co., Ltd., Japan). 2.6.3. Cavity Preparation Standardized Class V cavities were created on the buccal surfaces of each tooth using a high-speed handpiece equipped with a diamond bur (Horico Diament, Germany) under continuous water cooling. Dimensions were fixed at 3 mm (mesiodistal) × 2 mm (occlusogingival) × 1.5 mm (depth), with the occlusal margin 1 mm above the cementoenamel junction. Measurements were verified using a digital caliper. A new bur was used after every five cavities [ 16 ] eeth were sterilized by autoclaving at 121°C for 15 minutes and stored individually in sterile, sealed test tubes [ 17 ] 2.7. Experimental Grouping Teeth were randomly assigned to four groups: Group 1 (Negative Control) : No disinfection applied. Group 2 (Positive Control) : In Group 2, the chlorhexidine group (positive control), disinfection was performed using a 2% chlorhexidine gluconate solution (Grace for dental industries, Egypt) applied at a flow rate of 10 mL/min for 60 seconds. Following application, the cavity was rinsed with sterile saline and air-dried to remove any residual solution. [ 18 ] Group 3 (Diode Laser) : the diode laser group, a 980 nm diode laser (LASOTRONIX, Poland) was employed at a power of of 1 Watt in continuous mode. The cavity surface was irradiated for a total of 60 seconds, divided into two 30-second cycles. A 8mm tip was used, positioned 1 mm from the cavity in a perpendicular orientation, and moved in a scanning motion to ensure even coverage., spot size 8mm [ 9 ] Group 4 (Er:YAG Laser) : the Er:YAG laser group, was treated using a 2940 nm Er:YAG laser (Fotona: AT Fidelies Ljubljana, Slovenia) with settings including a pulse energy of 120 mJ, power output of 1.2 Watt, frequency of 10 Hz, water and air levels set to 4, and SP (short pulse) mode with a pulse duration of 300 microseconds. The irradiation was delivered using an R02 tipless handpiece spot size 0.9mm [ 12 ]. The power of Er: YAG laser was selected according to a pilot study conducted before the beginning of the main study. The range between 50 to 150 mj is considered safe regarding dentine morphology and mineralization .the pilot study was done using 50, 100, 120, 150 mj. Both 120 and 150 mj energy showed the highest antibacterial efficiency against streptococcus mutans bacteria with no statistically significant difference between them; so the energy of Er:YAG laser chosen was 120 mj. 2.8. Assessment of the effects of different treatment modalities : 2.8.1. Assessment of morphological changes of dentine via Scanning Electron Microscopy (SEM) Analysis Imaging was performed at base line to image the normal dentin then after application of each treatment modality to examine the morphological changes of dentine in each group. Samples were examined using a Quanta 250 FEG SEM equipped with an EDX unit. Imaging was performed at 30 kV with magnifications of ×2000 and ×6000. The resolution of the electron gun reached 1 nm. 2.8.2 Assessment of mineral content changes of dentine via Energy Dispersive X-ray (EDX) : Samples were examined using EDX device attached to Quanta 250 FEG SEM for analyzing the elemental and quantitative composition of dentin. 3. Restoration Procedures: Following disinfection and examination using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX), the cavities were etched with Prime Dent Etch (USA) for 20 seconds, rinsed with water for 10 seconds, and gently air-dried using an air syringe. Subsequently, a universal bonding agent (Prime and Bond Universal, Dentsply Sirona, Germany) was applied using a microbrush for 20 seconds, air-thinned for 5 seconds, and then light-cured for 10 seconds. The restoration procedure was carried out using Spectra ST HV Composite (Dentsply Sirona, Germany), applied in increments of 2 mm thickness. Each increment was individually light-cured for 20 seconds [ 19 ]. 4. Thermocycling Process The samples were immersed in distilled water at 37°C for 24 hours, followed by thermocycling for 78 seconds per cycle (30 seconds at 55°C, 10 seconds at ambient pause, 30 seconds at 5°C, and 8 seconds for the transition back to the initial condition). A total of 500 thermal cycles were performed using a TC-300 thermocycler (Vafai Factory) [ 20 ]. 5. Microleakage Testing 5.1. Sample Preparation for Dye Penetration Following thermocycling, all specimens were thoroughly dried, and their apical regions were sealed with sticky wax to prevent dye penetration. Two consecutive layers of nail varnish were then applied, leaving an uncoated gingival margin of approximately 1 mm and maintaining a 2 mm clearance from the tooth–restoration interface, thereby ensuring dye infiltration occurred exclusively at the interface region \[ 9 ]. The specimens were subsequently immersed in 2% methylene blue solution (Sparks, USA) for 24 hours at room temperature. After immersion, the teeth were rinsed, dried, and sectioned longitudinally along the buccolingual axis using a microtome (MTI Corporation, Richmond, CA)[ 21 ]. 5.2. Microleakage Assessment via Scanning Electron Microscopy (SEM) Analysis Assessment of linear dye penetration at tooth- restoration interface both occlusal and gingival was done using the Quanta 250 FEG SEM to study the degree of microleakage in micrometers. Statistical analysis: Mean and standard deviation values were calculated for each group under all test conditions. The data distribution was assessed for normality using the Kolmogorov-Smirnov and Shapiro-Wilk tests, confirming a parametric (normal) distribution. For comparisons involving more than two independent groups, one-way analysis of variance (ANOVA) was applied, followed by Tukey’s post hoc test for pairwise comparisons. The paired sample test was employed to analyze differences between two related groups. A significant level of p ≤ 0.05 was adopted for all statistical tests. Data analysis was conducted using IBM® SPSS® Statistics software, version 20 (IBM Corp., Armonk, NY, USA). Results 1) Morphological changes of dentine via SEM Analysis: SEM examination of dentine surface after cavity preparation and before application of different disinfection modalities (baseline) of all groups revealed relatively partial occlusion of dentinal tubules with presence of a smear layer figures (1,3and 5) SEM examination of dentine surface after application of CHO 2% showed an apparent narrowing of dentinal tubules with precipitation of some particle with lack of removal of the smear layer figure (2). SEM image of dentine after diode laser application showed an apparent widening of dentinal tubules with partial removal of the smear layer figure (4). SEM image of dentine after Er:YAG laser application showed an obvious widening of dentinal tubules with removal of the smear layer and melting of dentine figure (6). A) Chlorohexidine group: B) Diode laser 980 nm group: C)Er:YAG laser group: 2) Mineral content changes of dentine via EDX: I) Ca content changes: i. Relation between Pre and Post treatment values among all groups: As shown in table (1) and figure (7), A statistically significant difference was observed between the Pre and Post groups, with *p* < 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group. Relation between different groups according to Ca content: As presented in table (1) and figure (7), No statistically significant difference was observed between (CHX), (Diode laser) and (Er-YAG laser) where (p=0.372) in the pretreatment values of Ca content which means that the Ca content was standardized. There was a statistically significant difference between (CHX), (Diode laser) and (Er-YAG laser) post-treatment values where (p<0.001). A statistically significant difference was observed between the Er:YAG laser group and both the CHX and Diode laser groups (*p* < 0.001 for each comparison). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.941). The highest mean value was recorded in the Er:YAG laser group, whereas the lowest mean value was observed in the CHX group. Table (1): The mean, standard deviation (SD) values of Ca of different groups. Variables Ca Pre Post p-value Mean SD Mean SD CHX 58.89 1.18 42.90 0.82 <0.001* Diode laser 57.58 1.12 43.17 0.49 <0.001* Er-YAG laser 59.52 0.42 52.95 0.33 <0.001* p-value 0.372ns <0.001* *; significant (p0.05) Relation between different groups according to Ca percentage of change: As shown in table (2) and figure (8), A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* < 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* < 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.073). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group. Table (2): The mean, standard deviation (SD) values of percentage of change of Ca of different groups. Variables Ca Percentage of change Mean SD CHX 27.12% 0.69 Diode Laser 24.92% 0.82 Er-YAG laser 11.02% 0.45 p-value <0.001* *; significant (p<0.05) II) P content changes: i. Relation between Pre and Post treatment values among all groups: As shown in table (3) and figure (9), A statistically significant difference was observed between the Pre and Post groups, with *p* < 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group Relation between different groups according to P content As presented in table (3) and figure (9), no statistically significant difference was observed between (CHX), (Diode laser) and (Er-YAG laser) where ( p =0.719) in the pretreatment values of P content which means that the P content was standardized. There was a statistically significant difference between (CHX), (Diode laser) and (Er-YAG laser) where ( p <0.001). A statistically significant difference was observed between Er-YAG laser group and both CHX and Diode laser groups (*p* <0.001) for each comparison.No statistically significant difference was detected between the CHX and Diode laser groups where (*p* =0.950).The highest mean value was recorded in Er-YAG laser group, whereas the least mean value was observed in CHX group Table (3): The mean, standard deviation (SD) values of P of different groups. Variables P Pre Post p-value Mean SD Mean SD CHX 20.80 0.12 17.45 0.13 <0.001* Diode laser 20.49 0.39 17.58 0.44 <0.001* Er-YAG laser 20.71 0.23 19.93 0.22 <0.001* p-value 0.719ns <0.001* *; significant (p0.05) Relation between different groups according to P percentage of change: As shown in table (4) and figure (10), A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* < 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* < 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.050). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group. Table (4): The mean, standard deviation (SD) values of percentage of change of P of different groups Variables P Percentage of change Mean SD CHX 16.09% 0.45 Diode Laser 14.29% 0.64 Er-YAG laser 3.76% 0.32 p-value <0.001* *; significant (p<0.05) II) Ca/P ratio changes: i. Relation between Pre and Post treatment values among all groups: As shown in table (5) and figure (11), A statistically significant difference was observed between the Pre and Post groups, with *p* < 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group Relation between different groups according to Ca/P ratio changes: As presented in table (5) and figure (11), there was no statistically significant difference observed between CHX group, Diode laser group and Er-YAG laser group where ( *p* =0.785) in the pretreatment values of Ca/P ratio which means that the Ca/P ratio was standardized. Statistically significant difference was observed between the CHX, Diode laser and Er-YAG laser groups ( *p* =0.030). A statistically significant difference was detected between Er-YAG laser group and each of CHX and Diode laser groups ( *p* =0.040) and ( *p* =0.043). No statistically significant difference was detected between CHX l group and Diode laser group ( *p* =0.996).The highest mean value was recorded in Er-YAG lase group, while the lowest mean value was observed in CHX group. Table (5): The mean, standard deviation (SD) values of Ca/P ratio of different groups. Variables Ca/P ratio Pre Post p-value Mean SD Mean SD CHX 2.83 0.06 2.46 0.06 <0.001* Diode laser 2.82 0.08 2.47 0.07 <0.001* Er-YAG laser 2.88 0.03 2.66 0.03 <0.001* p-value 0.785ns 0.030* *; significant (p0.05) Relation between different groups according to Ca/ P ratio percentage of change: As shown in table (6) and figure (12), A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* < 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* < 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.712). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group. Table (6): The mean, standard deviation (SD) values of percentage of change of Ca/P of different groups. Variables Ca/P Percentage of change Mean SD CHX 13.14% 0.63 Diode Laser 12.38% 0.94 Er-YAG laser 7.55% 0.34 p-value <0.001* *; significant (p<0.05) 3) Microleakage Assessment via SEM: Microleakage results were summarized in table (7) and Figure (13). Figures (14, 15, 16 and 17) Illustrate SEM images of dye penetration along the tooth-restoration interface. At occlusal margin of the cavity: A Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups ( *p* <0.001). Comparisons revealed significant differences between the Control group and both of Er-YAG laser and Diode laser groups ( *p* <0.001), meanwhile no statistically significant difference was observed between the Control and CHX groups ( *p* =0.999). A statistically significant difference was observed between the CHX group and each of Er-YAG laser and Diode laser groups ( *p* <0.001). Also, a statistically significant difference was observed between the Er-YAG laser and Diode laser groups ( *p* =0.006). The highest mean value was recorded in the Control, group whereas the lowest mean value was observed in the Er-YAG laser group. 2-At gingival margin of the cavity: A Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups ( *p* <0.001). Comparisons revealed significant differences between the Control group and each of CHX, Er-YAG laser and Diode laser groups ( *p* <0.001), A statistically significant difference was observed detected CHX group and each of Er-YAG laser and Diode laser groups ( *p* <0.001) and ( *p* =0.008). Also, a statistically significant difference was observed between Er-YAG laser and Diode laser groups ( *p* <0.001). The highest mean value was recorded in the Control group whereas the lowest mean value was observed in the Er-YAG laser group. 3-Average of microleakage both occlusally and gingivally: A Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups ( *p* <0.001). Comparisons revealed significant differences between the Control group and each of CHX, Er-YAG laser and Diode laser groups ( *p* <0.001). A statistically significant difference was detected between the CHX group and each of Er-YAG laser and Diode laser groups ( *p* <0.001). Also, a statistically significant difference was found between Er-YAG laser and Diode laser groups ( *p* <0.001). The highest mean value was recorded in the Control group whereas the lowest mean value was observed in the Er-YAG laser group. Table (7): The mean, standard deviation (SD) values of microleakage of different groups. Variables Microleakage Occlusal Gingival Average Mean SD Mean SD Mean SD Control 7.45 0.35 15.17 0.25 11.31 0.11 CHX 7.44 1.14 6.60 1.10 7.02 0.02 Diode laser 4.96 1.30 5.69 0.27 5.33 0.79 Er-YAG laser 3.52 0.51 1.34 0.24 2.44 0.22 p-value <0.001* <0.001* <0.001* *; significant (p<0.05) Discussion Contemporary caries removal techniques do not reliably eradicate all microorganisms from the prepared cavity. Several studies have shown that bacteria may persist within the dentin even following the application of caries detector dyes. Furthermore, research indicates that fermentative microorganisms can survive beneath restorations lacking antiseptic properties for up to 139 days. Consequently, the incorporation of cavity disinfection as an adjunct to conventional caries removal procedures is recommended to eliminate residual microbial contamination. This approach may help reduce the risk of secondary caries, postoperative pulp sensitivity, and pulpal inflammation prior to definitive restoration [ 22 ]. The infiltration of Bacterial cells, nutrient compounds, or hydrogen ions derived from dental plaque into the interface between the tooth and restorative material can result in complications such as marginal discoloration, fractures, secondary caries, corrosion, sensitivity, and pulpal inflammation [ 23 ] Numerous studies have advocated for various cavity disinfection methods, encompassing chemical agents, lasers, ozone therapy, and other modalities [ 9 ]. Chlorhexidine digluconate (CHX) is a potent antimicrobial agent recognized for its effective inhibition of streptococcal growth, rendering it a promising candidate for the prevention of dental caries. Upon application to dentin surfaces, CHX exerts a prolonged antibacterial effect by the sustained release of positively charged molecules, a phenomenon known as substantive antimicrobial activity (SAA) [ 23 ]. 2% concentration of chlorhexidine digluconate (CHX) was employed in this study due to its widespread use in both clinical dentistry and research. This aqueous formulation is generally considered biocompatible and exhibits an acceptable toxicological profile, rendering it a reliable and effective choice for cavity disinfection [ 24 ]. Although CHX has a widely proven effect Haralur et al., found that it has a negative effect on dentine regarding Ca content and hardness [ 5 ] also it negatively impacts the bonding and sealing of adhesive restorations to dentin, potentially leading to increased microleakage [ 3 ]. Laser has been widely used as an efficient dental cavity disinfectant; it has a potent antibacterial effect with avoidance of the side effects of using chemicals and it has some positive effects on dentine such as removal of smear layer which consequently leads to improvement of bonding between dentine and restoration [ 4 , 12 , 25 , and 26 ] The interaction between the laser and tissue is greatly influenced by the laser's wavelength and the power density applied [ 4 ]. Diode lasers are available in four main wavelengths: 810–830 nm, 940 nm, 980 nm, and 1064 nm. Their antibacterial effectiveness is largely attributed to the thermal effects and the corresponding rise in temperature generated during irradiation. Diode laser 980 nm was chosen in our study because of its potent antibacterial efficacy beside its ability to remove the smear layer [ 25 ] Low-energy Er:YAG laser treatment modifies the dentin surface by efficiently removing debris and exposing open dentinal tubules. Researches indicated that the heat generated by the Er:YAG laser can neutralize free radicals and alter the dentin surface, thereby enhancing its suitability for bonding [ 7 ]. Operating at a wavelength of 2.94 µm, the Er:YAG laser has demonstrated bactericidal effects against Streptococcus mutans. In this study, a low energy output of 1.2 watts was utilized to minimize thermal damage to dentin and avoid potential reductions in dentin hardness. This parameter selection is supported by Du et al., who found that power settings between 1 and 1.5 watts effectively reduce S. mutans levels without compromising dentin integrity [ 27 ]. Scanning electron microscopy (SEM) was employed in this study to evaluate the ultrastructural changes on the dentin surface following the application of the tested treatments, owing to its capability to provide both qualitative and quantitative assessment of morphological features [ 28 ]. Scanning electron microscopy analysis of dentin treated with 2% chlorhexidine demonstrated irregular dentinal tubules characterized by partial occlusion and the presence of residual smear layer. The findings corroborate those presented in prior research by Lapinska et al. [ 29 ], who observed multiple and singular deposits irregularly distributed across the dentine surface, located both within pits created by mechanical preparation and on the smooth areas of the sample. Similarly, Siwnata et al. [ 30 ] reported that 2% chlorhexidine gluconate was insufficient for complete removal of the smear layer during cavity cleansing, resulting in the persistence of smear plugs that impeded the full opening of dentinal tubules. In the present study, dentin treated with diode laser at a power setting of 1 W exhibited an irregular surface with an apparent opening of dentinal tubules with partial removal of smear layer. Our findings are in line with prior research outcomes by Behniafar et al., who also observed that the application of a diode laser at 1 W power output and a wavelength of 980 nm did not result in a significant increase in pulpal temperature or cause structural damage such as fissures or cracks on the dentin surface with partial removal of smear layer [ 31 ]. These outcomes contradict earlier reported data of Jhingan et al. [ 25 ] and El Tayeba et al. [ 4 ] who stated that total smear layer and debris removal, accompanied by morphological changes such as dentin melting, these findings may be attributed to the higher power used in their study as both of them employed diode laser at 2 W and 1.5 respectively. Another study conducted by Abdou et al. [ 28 ] achieved effective smear layer removal and complete opening of dentinal tubules using a diode laser at 1.5 W. although the previously used parameters produced an efficient smear layer removal but they may produce harmful effects on the pulp according to Jaine et al who found that both 1 W and 2W had similar antibacterial effects when used for dentine disinfection but found that 1 W was safer than 2 W for the pulp which produced higher temperature rise of the pulp [ 32 ] In our study dentine surface treated with erbium yag laser showed an obvious widening of dentinal tubules with total removal of smear layer. These findings were in alignment with Vieira et al., and Wang et al., who reported that dentin surfaces treated with Erbium:YAG laser exhibited open dentinal tubules and were free of smear layer, resulting in a retentive surface pattern that can improve bonding to dentin [ 16 , 26 ]. A study conducted by found Burlat et al. hat using Er:YAG laser with a power range between 250–300 mj led to surface cracks and disintegration of dentine but these findings may be the result of the high laser power used in his study, this was in agreement with another study conducted by Wanderley et al., [ 33 , 34 ] Calcium (Ca) and phosphorus (P), which are found in hydroxyapatite crystals, make up the primary inorganic components of dental hard tissues. Changes in the Ca/P ratio can disrupt the natural balance between the organic and inorganic components, possibly altering the structural properties of dentin, including its permeability and solubility. [ 35 ] In our study, Edx was used to the change in mineral content of dentine after different disinfection modalities, it was chosen because of its accuracy and sensitivity in measuring mineral content [ 28 ]. EDX values of Ca and P of all experimental groups exhibited lower Ca/P weight ratios compared to their control (untreated) samples. The observed decrease in calcium and phosphorus levels following chlorhexidine (CHX) application aligns with the findings reported by Haralur et al. and Kimyai et al. [ 5 ]. This decrease Can be ascribed to the cationic nature of CHX, which enables it to bind readily to anionic molecules, such as the phosphate groups present in hydroxyapatite resulting in the displacement and subsequent release of calcium ions (Ca) from dentin ;these findings suggest that CHX may contribute to calcium ion removal through its interaction with phosphate [ 3 , 5 , 36 ]. Regarding diode laser Statistical analysis indicated a significant difference between values recorded before and after treatment regarding calcium and phosphorous content, this was in accordance with Azmy et al who found that diode laser as a surface treatment resulted in observable changes in the mineral content of radicular dentin [ 37 ]. In contrast with our findings, Abdou et al, claimed that no chemical changes in dentin components following diode laser application. These results may be attributed to the use of distilled water as an irrigant immediately before the application of the 980 nm diode laser on the dentin surface which may lead to absorbance of heat produced by the photothermal effect of diode laser thereby preserving the inorganic content of the dentin without causing any alteration in the mineral content [ 28 ]. Er:YAG laser treatment resulted in the smallest percentage change in calcium and phosphorus content. These findings are consistent with those of Soares et al. [47], who reported that Er:YAG laser irradiation at an energy setting of 100 mJ caused only minimal alterations in the elemental composition of the treated surface, along with a slight reduction in the calcium-to-phosphorus (Ca/P) ratio. On the contrary, Moosavi [ 39 ] has reported that Er:YAG laser irradiation led to an increase in microhardness and calcium ion content in dentine; however, these differences were not statistically significant when compared to their respective control groups. Microleakage is defined as the infiltration of oral fluids, molecules, bacteria, and ions at the interface between the cavity walls and the restorative material. Preventing microleakage is crucial for ensuring the longevity and clinical success of dental restorations. [ 11 ]. As a matter of fact, an ideal cavity disinfectant should offer effective antimicrobial activity while maintaining the sealing integrity of restorative materials. Compromising this seal can lead to marginal leakage, which may reduce the longevity of the restoration by allowing bacteria and fluids to infiltrate the interface between the tooth and the restorative material [ 14 ]. Microleakage can be evaluated using various techniques, among these, dye penetration technique which was used in our study, is one of the most commonly used methods in recent research due to its practicality—dye solutions are readily available, the method does not involve reactive chemicals or radiation, and it is both highly feasible and easily reproducible. [ 31 ] Thermal cycling is widely employed in in vitro studies. This technique is particularly valuable in microleakage research, as it effectively simulates the clinical aging process of dental restorations in the oral cavity. In the present study, all specimens in our study were subjected to 5,000 thermal cycles between 5°C and 55°C prior to microleakage assessment [ 15 ] The group treated with chlorhexidine exhibited a lower level of microleakage at the tooth–restoration interface when compared to control group. These findings are consistent with the studies conducted by Ramezanian et al., [ 38 ] which reported that chlorhexidine significantly reduces microleakage both immediately following restoration and over time. Similarly, a review by Satpute highlighted chlorhexidine’s role in enhancing the longevity of restorative materials [ 39 ] However, The study outcomes disagree with a study by Mutluay et al. who reported that chlorhexidine had no significant effect on microleakage compared to the control group. This discrepancy may be attributed to differences in experimental protocols, particularly the duration of chlorhexidine application and the type of restorative material used; their study employed a giomer-based restoration, whereas composite resin was used in the present study [ 2 ]. In our study, diode laser 980 nm group exhibited a lower microleakage value when compared with control and chlorohexidine groups. These findings were consistent with of El Mansy et al., who reported that the use of a 980 nm diode same power and time laser resulted in the lowest statistically significant microleakage levels when compared to CHX and control groups. In contrast, Ipek et al. found no significant improvement in microleakage following diode laser treatment, this discrepancy may be attributed to variations in laser parameters used across studies which are employing a different application time and utilizing a different restorative material [ 9 ]. In relation to the Er:YAG laser, our results indicated that it produced the lowest levels of microleakage among all groups tested A study by Emilie Luong and Amir Shayegan demonstrated that Er:YAG laser conditioning of enamel and dentin surfaces beneath resin composite has a great potential to reduce microleakage [ 40 ] A study by Sharafeddin and Tabrizi found that the Er:YAG laser had a favorable effect in reducing microleakage at both occlusal and gingival margins when compared to CO2 laser [ 7 ]. Similarly, a study conducted by Ipek Aslan et al. found that the Er,Cr:YSGG laser group demonstrated superior performance in reducing nanoleakage compared to the diode laser and chlorhexidine groups. [ 17 ]. . According to our knowledge, there is no previous study that compared Er:YAG laser with diode laser or chlorohexidine for cavity disinfection or compared between their effect on the morphology of dentine. Conclusion Within the limitations of this study, it can be concluded that the Erbium:YAG laser demonstrated the most favorable outcomes in terms of preserving and enhancing both the morphological and chemical composition of dentin. Moreover, it resulted in the lowest microleakage values among all tested groups, indicating superior sealing ability and potential for long-term restoration success. Both the diode laser and 2% chlorhexidine (CHX) showed beneficial effects compared to the control, with no significant difference between them CHX exhibited the highest microleakage values, suggesting a less favorable impact on the marginal integrity of restorations. Declarations Competing interests: The authors declare no conflicts of interest related to this study. 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Additional Declarations There is no conflict of interest Cite Share Download PDF Status: Published Journal Publication published 15 Jan, 2026 Read the published version in BDJ Open → Version 1 posted Editorial decision: revise 27 Aug, 2025 Submission checks completed at journal 21 Aug, 2025 Editor assigned by journal 11 Aug, 2025 First submitted to journal 11 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7345490","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":506274234,"identity":"2b2ed951-429d-4793-8019-f9d8f3420f61","order_by":0,"name":"menna 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layer\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/0d65fb6e075da2d207452521.jpg"},{"id":91106772,"identity":"c63d8d01-139a-4be0-9626-9f60578a84d1","added_by":"auto","created_at":"2025-09-11 15:38:53","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":178723,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of dentine after Er:YAG laser application, showing an obvious widening of dentinal tubules with removal of the smear layer\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/2a24cfd457f897fbf6e5ac3e.jpg"},{"id":91106766,"identity":"0aa3eb87-965e-4f5e-b985-4ee81b5a0045","added_by":"auto","created_at":"2025-09-11 15:38:52","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":27718,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing Ca of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/873b97d5b74ac50846970d0c.jpg"},{"id":91107259,"identity":"6773f41b-d056-4a55-a0fa-ac0e86a22b3b","added_by":"auto","created_at":"2025-09-11 15:46:51","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":30869,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing percentage of change of Ca of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/75c7b55862844e081a52f1eb.jpg"},{"id":91106743,"identity":"1fa9c27b-6a1d-4fc1-9191-433a7d7dd42c","added_by":"auto","created_at":"2025-09-11 15:38:51","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":33829,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing P of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/79958fe4b937f0f77dbd51a5.jpg"},{"id":91106731,"identity":"619081f2-804a-46ca-a65a-074666ac790a","added_by":"auto","created_at":"2025-09-11 15:38:49","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":37728,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing percentage of change of P of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/d314de18c88a027687e355de.jpg"},{"id":91106735,"identity":"34fd862a-d8ea-418d-b9c7-125ea9582252","added_by":"auto","created_at":"2025-09-11 15:38:50","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":38083,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing Ca/P of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/09658a7669f1998b1993cfb3.jpg"},{"id":91106771,"identity":"1fdcf5d6-4d03-4820-b1e8-4d8e8f853891","added_by":"auto","created_at":"2025-09-11 15:38:53","extension":"jpg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":30942,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing percentage of change of Ca/P of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture12.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/f5f5a6d03192860d3df9cb4e.jpg"},{"id":91106775,"identity":"7badf394-79e2-40cd-ad91-b5d0c39af225","added_by":"auto","created_at":"2025-09-11 15:38:53","extension":"jpg","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":32936,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBar chart representing microleakage of different groups\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture13.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/45706484b3eaf9fe0df37aa5.jpg"},{"id":91106751,"identity":"2c87fa86-714a-4254-b96a-b609b718d545","added_by":"auto","created_at":"2025-09-11 15:38:52","extension":"jpg","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":140482,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of dye penetration along tooth-restoration interface in the control group (untreated dentin) (Group 1).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture14.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/61472c8cdf54bfd1801647fd.jpg"},{"id":91106745,"identity":"5363a229-ed1e-4943-a57f-467c67a7ed37","added_by":"auto","created_at":"2025-09-11 15:38:51","extension":"jpg","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":112928,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of dye penetration along tooth-restoration interface in the CHX treated group (Group 2).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture15.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/7170caee9184498bb4e3ce6e.jpg"},{"id":91106744,"identity":"728c3682-464c-4e67-ace0-5b7ed5afbc67","added_by":"auto","created_at":"2025-09-11 15:38:51","extension":"jpg","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":107428,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of dye penetration along tooth-restoration interface in the diode laser treated group (Group 3).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture16.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/bb79b9cd98d6d0c4e14183b9.jpg"},{"id":91107264,"identity":"ccc58660-7a21-42eb-a743-ecd9e8a26be7","added_by":"auto","created_at":"2025-09-11 15:46:52","extension":"jpg","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":107247,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM image of dye penetration along tooth-restoration interface in the Er:YAG laser treated group (Group 4).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture17.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/e7ada14f962b4dc324aab9a4.jpg"},{"id":100398862,"identity":"9688ff45-6ab4-4157-8651-d3d50d3e02b5","added_by":"auto","created_at":"2026-01-16 11:55:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4429689,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7345490/v1/96a8f2e4-cf5d-4483-bc9a-5280fd91ea0b.pdf"}],"financialInterests":"There is no conflict of interest","formattedTitle":"The effect of Chlorohexidine, Er:YAG Laser and Diode Laser 980 nm as Dental Cavity Disinfectants on Dentine Morphology and Microleakage of Composite Restoration: An In Vitro Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDental caries is a highly prevalent condition globally that represents a multifactorial disease arising from the complex interplay between cariogenic bacteria, dietary sugars, and host-related factors. These microorganisms metabolize dietary sugars, generating acids that gradually demineralize the tooth's hard tissues, ultimately resulting in tooth decay [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eCervical caries is a common form of tooth decay, often resulting from poor oral hygiene, and a highly cariogenic diet. Residual microorganisms can persist even after thorough mechanical preparation, particularly in cases of incomplete caries removal. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThese bacteria may penetrate the restoration-tooth interface, promoting microleakage and increasing the risk of secondary or recurrent caries⁽\u0026sup1;\u0026sup1;⁾. To minimize this risk, disinfecting the dentin surface is recommended following cavity preparation and before placing any restorative material [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAdditionally, a smear layer formed during cavity preparation can be a barrier preventing adequate bonding between composite resin restoration and dentine and disinfectants from effectively penetrating the dentinal tubules [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDentin, a mineralized tissue, is composed of both organic and inorganic components. Its inorganic portion mainly consists of hydroxyapatite crystals containing calcium (Ca) and phosphorus (P). The typical calcium-to-phosphorus (Ca/P) ratio in dentin hydroxyapatite is approximately 1.67, which reflects a stable and consistent mineral composition. However, this ratio can vary depending on crystal type, calcium availability, anatomical location, and measurement method [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eChemical agents used during dental procedures may alter the Ca/P ratio, leading to changes in the structural and chemical integrity of dentin, including its permeability and solubility which can consequently disrupt the balance between dentin\u0026rsquo;s organic and inorganic components and negatively impact its physical properties such as micro-hardness and roughness. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eFurthermore, these chemical agents can lead to a reduction in mineral content that may compromise the mechanical strength and have a direct impact on bonding between dentine and restorative material which can affect the long-term durability of the restoration [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eSo, Microleakage, defined as the undetectable seepage of fluids, bacteria, or ions between the tooth structure and restoration, is a leading cause of clinical failure [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. It may lead to tooth discoloration, postoperative sensitivity, recurrent decay, and pulpal complications. Therefore, optimizing disinfection protocols and improving adhesive bonding are crucial for reducing bacterial contamination, enhancing marginal integrity, and ensuring the longevity of composite restorations [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eChlorhexidine (CHX) is widely regarded as the gold standard for cavity disinfection due to its strong antimicrobial properties and its ability to bind to bacterial amino acids. Studies have shown that concentrations of up to 10% are considered safe for use on living tissues [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, Chlorhexidine (CHX) lacks the ability to dissolve tissue and effectively remove the smear layer. As a result, the residual smear layer can act as a barrier, reducing the contact time between the irrigant and the dentin [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn the recent years, lasers have gained popularity in dentistry due to their broad range of applications; one of these applications is dental cavity disinfection. In addition to effectively penetrating and eliminating bacteria, they can also seal dentinal tubules, thereby preventing potential pathways for bacterial reinfection. Lasers have the ability of removal of smear layer, consequently increasing the bonding strength between restorative material and dentine. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eAmong the lasers that are widely used as cavity disinfectants; Diode 980nm and Erbium YAG 2840nm. \"Diode lasers offer the advantage of effectively removing the smear layer and inducing melting of the dentin surface with partial to complete obliteration of dentinal tubules [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eLow-energy Er:YAG laser treatment modifies the dentin surface by efficiently eliminating debris and revealing open dentinal tubules. Research indicates that the heat produced by the Er:YAG laser can neutralize free radicals and alter the dentin, resulting in a surface more favorable for bonding [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eAccording to our knowledge, there is no study compared the effect of chlorohexidine, diode laser 980 nm and Er:YAG laser when used for dentine disinfection, on dentine morphology and mineral content. Therefore, this study was conducted to assess the morphological changes and mineral content of dentine using a scanning electron microscope and EDX and to evaluate microleakage of composite resin restoration using SEM.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Study Design\u003c/h2\u003e\u003cp\u003eThis in vitro experimental study adhered to the CRIS Guidelines (Checklist for Reporting In-vitro Studies) published in 2014 to ensure methodological transparency and research quality [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. A total of 40 freshly extracted human primary molars were used. To minimize structural variability, extractions were performed at or near the natural exfoliation period.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Ethical Considerations\u003c/h2\u003e\u003cp\u003eThe authors bear full accountability for all aspects of the research, guaranteeing that any issues related to the accuracy or integrity of any component are rigorously investigated and appropriately resolved. All procedures were executed in full compliance with the ethical principles set forth in the Declaration of Helsinki. Informed consent was secured from all participants prior to their involvement in the study. The experimental protocol was reviewed and approved by the Medical Research Ethics Committee of the National Research Centre (approval no1234052022.). 0n 7/4/2022\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Sample Size Calculation\u003c/h2\u003e\u003cp\u003eSample size was determined based on a previous study by Jamel and Taher (2024), which evaluated the antibacterial efficacy of a 940 nm diode laser on \u003cem\u003eStreptococcus mutans\u003c/em\u003e and other cariogenic bacteria. Their study reported mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD of CFU as 34\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8 in Group I and 25\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6 in Group II, yielding an effect size of 1.86. Using a power of 0.9 and a significance level (α) of 0.05, the minimum required sample size was calculated to be 8 per group. To account for a potential 20% dropout, this was increased to 10 per group. The calculation was conducted using a t-test in G*Power software (version 3.1.4.9) [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Randomization and Allocation\u003c/h2\u003e\u003cp\u003eAll 40 extracted teeth were labeled numerically (1\u0026ndash;40) and stored in a sterile, sealed, opaque container. Random allocation into four equal groups (n\u0026thinsp;=\u0026thinsp;10) was carried out using a computer-generated random sequence from \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e\u003ca href=\"http://www.random.org\" target=\"_blank\"\u003ewww.random.org\u003c/a\u003e\u003c/span\u003e\u003cspan address=\"http://www.random.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e on November 12, 2024, applying a 1:1 allocation ratio.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5. Blinding\u003c/h2\u003e\u003cp\u003eA double-blind design was adopted. Both the SEM and EDX examiners and the statistician performing the data evaluation were blinded to the group assignments.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6. Specimen Selection and Preparation\u003c/h2\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.6.1. Inclusion and Exclusion Criteria\u003c/h2\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eInclusion criteria\u003c/b\u003e: Sound freshly extracted primary molars with at least 50% of root structure intact.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eExclusion criteria\u003c/b\u003e: Teeth with cracks, restorations, deep caries, pulpal involvement, structural anomalies, or prior dental treatment were excluded.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e2.6.2. Collection and Storage\u003c/h2\u003e\u003cp\u003eTeeth were collected from the outpatient pediatric dentistry clinic of the NRC. An informed parental consent was obtained before extraction. Parents were briefed about the study involving their child\u0026rsquo;s extracted teeth. Following extraction, the teeth were rinsed with tap water, residual soft tissues were carefully removed using a scalpel, and the crowns were gently cleaned with a soft-bristled brush (Sulcus, Oral-B, Mexico). Prior to analysis, the specimens were stored in deionized water at 4\u0026deg;C [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The structural integrity of all samples was first assessed through visual inspection, followed by examination under a stereoscope (Olympus Optical Co., Ltd., Japan).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e2.6.3. Cavity Preparation\u003c/h2\u003e\u003cp\u003eStandardized Class V cavities were created on the buccal surfaces of each tooth using a high-speed handpiece equipped with a diamond bur (Horico Diament, Germany) under continuous water cooling. Dimensions were fixed at 3 mm (mesiodistal) \u0026times; 2 mm (occlusogingival) \u0026times; 1.5 mm (depth), with the occlusal margin 1 mm above the cementoenamel junction. Measurements were verified using a digital caliper. A new bur was used after every five cavities [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] eeth were sterilized by autoclaving at 121\u0026deg;C for 15 minutes and stored individually in sterile, sealed test tubes [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e2.7. Experimental Grouping\u003c/h2\u003e\u003cp\u003eTeeth were randomly assigned to four groups:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 1 (Negative Control)\u003c/b\u003e: No disinfection applied.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 2 (Positive Control)\u003c/b\u003e: In Group 2, the chlorhexidine group (positive control), disinfection was performed using a 2% chlorhexidine gluconate solution (Grace for dental industries, Egypt) applied at a flow rate of 10 mL/min for 60 seconds. Following application, the cavity was rinsed with sterile saline and air-dried to remove any residual solution. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 3 (Diode Laser)\u003c/b\u003e: the diode laser group, a 980 nm diode laser (LASOTRONIX, Poland) was employed at a power of of 1 Watt in continuous mode. The cavity surface was irradiated for a total of 60 seconds, divided into two 30-second cycles. A 8mm tip was used, positioned 1 mm from the cavity in a perpendicular orientation, and moved in a scanning motion to ensure even coverage., spot size 8mm [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 4 (Er:YAG Laser)\u003c/b\u003e: the Er:YAG laser group, was treated using a 2940 nm Er:YAG laser (Fotona: AT Fidelies Ljubljana, Slovenia) with settings including a pulse energy of 120 mJ, power output of 1.2 Watt, frequency of 10 Hz, water and air levels set to 4, and SP (short pulse) mode with a pulse duration of 300 microseconds. The irradiation was delivered using an R02 tipless handpiece spot size 0.9mm [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The power of Er: YAG laser was selected according to a pilot study conducted before the beginning of the main study. The range between 50 to 150 mj is considered safe regarding dentine morphology and mineralization .the pilot study was done using 50, 100, 120, 150 mj. Both 120 and 150 mj energy showed the highest antibacterial efficiency against streptococcus mutans bacteria with no statistically significant difference between them; so the energy of Er:YAG laser chosen was 120 mj.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e2.8. \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eAssessment of the effects of different treatment modalities\u003c/span\u003e:\u003c/h2\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e2.8.1. \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eAssessment of morphological changes of dentine via Scanning Electron Microscopy (SEM) Analysis\u003c/span\u003e\u003c/h2\u003e\u003cp\u003eImaging was performed at base line to image the normal dentin then after application of each treatment modality to examine the morphological changes of dentine in each group.\u003c/p\u003e\u003cp\u003eSamples were examined using a Quanta 250 FEG SEM equipped with an EDX unit. Imaging was performed at 30 kV with magnifications of \u0026times;2000 and \u0026times;6000. The resolution of the electron gun reached 1 nm.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e2.8.2 \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eAssessment of mineral content changes of dentine via Energy Dispersive X-ray (EDX)\u003c/span\u003e:\u003c/h2\u003e\u003cp\u003eSamples were examined using EDX device attached to Quanta 250 FEG SEM for analyzing the elemental and quantitative composition of dentin.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\n\u003ch3\u003e3. Restoration Procedures:\u003c/h3\u003e\n\u003cp\u003eFollowing disinfection and examination using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX), the cavities were etched with Prime Dent Etch (USA) for 20 seconds, rinsed with water for 10 seconds, and gently air-dried using an air syringe.\u003c/p\u003e\u003cp\u003eSubsequently, a universal bonding agent (Prime and Bond Universal, Dentsply Sirona, Germany) was applied using a microbrush for 20 seconds, air-thinned for 5 seconds, and then light-cured for 10 seconds.\u003c/p\u003e\u003cp\u003eThe restoration procedure was carried out using Spectra ST HV Composite (Dentsply Sirona, Germany), applied in increments of 2 mm thickness. Each increment was individually light-cured for 20 seconds [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003e4. Thermocycling Process\u003c/h3\u003e\n\u003cp\u003eThe samples were immersed in distilled water at 37\u0026deg;C for 24 hours, followed by thermocycling for 78 seconds per cycle (30 seconds at 55\u0026deg;C, 10 seconds at ambient pause, 30 seconds at 5\u0026deg;C, and 8 seconds for the transition back to the initial condition). A total of 500 thermal cycles were performed using a TC-300 thermocycler (Vafai Factory) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003e5. Microleakage Testing\u003c/h3\u003e\n\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e5.1. \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eSample Preparation for Dye Penetration\u003c/span\u003e\u003c/h2\u003e\u003cp\u003eFollowing thermocycling, all specimens were thoroughly dried, and their apical regions were sealed with sticky wax to prevent dye penetration. Two consecutive layers of nail varnish were then applied, leaving an uncoated gingival margin of approximately 1 mm and maintaining a 2 mm clearance from the tooth\u0026ndash;restoration interface, thereby ensuring dye infiltration occurred exclusively at the interface region \\[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The specimens were subsequently immersed in 2% methylene blue solution (Sparks, USA) for 24 hours at room temperature. After immersion, the teeth were rinsed, dried, and sectioned longitudinally along the buccolingual axis using a microtome (MTI Corporation, Richmond, CA)[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003e5.2. \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eMicroleakage Assessment via Scanning Electron Microscopy (SEM) Analysis\u003c/span\u003e\u003c/h2\u003e\u003cp\u003eAssessment of linear dye penetration at tooth- restoration interface both occlusal and gingival was done using the Quanta 250 FEG SEM to study the degree of microleakage in micrometers.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis:\u003c/h2\u003e\u003cp\u003eMean and standard deviation values were calculated for each group under all test conditions. The data distribution was assessed for normality using the Kolmogorov-Smirnov and Shapiro-Wilk tests, confirming a parametric (normal) distribution. For comparisons involving more than two independent groups, one-way analysis of variance (ANOVA) was applied, followed by Tukey\u0026rsquo;s post hoc test for pairwise comparisons. The paired sample test was employed to analyze differences between two related groups. A significant level of \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026le;\u0026thinsp;0.05 was adopted for all statistical tests. Data analysis was conducted using IBM\u0026reg; SPSS\u0026reg; Statistics software, version 20 (IBM Corp., Armonk, NY, USA).\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cu\u003e1) Morphological changes of dentine via SEM Analysis:\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM examination of dentine surface after cavity preparation and before application of different disinfection modalities (baseline) of all groups revealed relatively partial occlusion of dentinal tubules with presence of a smear layer \u003cstrong\u003efigures (1,3and 5)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM examination of dentine surface after application of CHO 2% showed an apparent narrowing of dentinal tubules with precipitation of some particle with lack of removal of the smear layer \u003cstrong\u003efigure (2).\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM image of dentine after diode laser application showed an apparent widening of dentinal tubules with partial removal of the smear layer \u003cstrong\u003efigure (4).\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM image of dentine after Er:YAG laser application showed an obvious widening of dentinal tubules with removal of the smear layer and melting of dentine \u003cstrong\u003efigure (6).\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eA) Chlorohexidine group:\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eB) Diode laser 980 nm group:\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eC)Er:YAG laser group:\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003e2) Mineral content changes of dentine via EDX:\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eI)\u003c/strong\u003e \u003cstrong\u003eCa content changes:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ei. Relation between Pre and Post treatment values among all groups:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (1) and figure (7),\u003c/strong\u003e A statistically significant difference was observed between the Pre and Post groups, with *p* \u0026lt; 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group.\u003c/p\u003e\n\u003col start=\"2\"\u003e\n \u003cli\u003e\u003cstrong\u003eRelation between different groups according to Ca content:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cstrong\u003eAs presented in table (1) and figure (7),\u003c/strong\u003e No statistically significant difference was observed between (CHX), (Diode laser) and (Er-YAG laser) where (p=0.372) in the pretreatment values of Ca content which means that the Ca content was standardized.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere was a statistically significant difference between (CHX), (Diode laser) and (Er-YAG laser) post-treatment values where (p\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was observed between the Er:YAG laser group and both the CHX and Diode laser groups (*p* \u0026lt; 0.001 for each comparison). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.941). The highest mean value was recorded in the Er:YAG laser group, whereas the lowest mean value was observed in the CHX group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (1): The mean, standard deviation (SD) values of Ca of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"111%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e58.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e42.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e57.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e1.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e43.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e59.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e52.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.372ns\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp; \u0026nbsp;ns; non-significant (p\u0026gt;0.05)\u0026nbsp;\u003c/p\u003e\n\u003col start=\"3\"\u003e\n \u003cli\u003e\u003cstrong\u003eRelation between different groups according to Ca\u003c/strong\u003e \u003cstrong\u003epercentage of change:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (2) and figure (8),\u003c/strong\u003e A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* \u0026lt; 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* \u0026lt; 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.073). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (2): The mean, standard deviation (SD) values of percentage of change of Ca of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"116%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage of change\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e27.12%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode Laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e24.92%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e11.02%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eII)\u003c/strong\u003e \u003cstrong\u003eP content changes:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ei. Relation between Pre and Post treatment values among all groups:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (3) and figure (9),\u003c/strong\u003e A statistically significant difference was observed between the Pre and Post groups, with *p* \u0026lt; 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRelation between different groups according to P content\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs presented in \u003cstrong\u003etable (3) and figure (9),\u003c/strong\u003e no statistically significant difference was observed between (CHX), (Diode laser) and (Er-YAG laser) where (\u003cem\u003ep\u003c/em\u003e=0.719) in the pretreatment values of P content which means that the P content was standardized.\u003c/p\u003e\n\u003cp\u003eThere was a statistically significant difference between (CHX), (Diode laser) and (Er-YAG laser) where (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was observed between Er-YAG laser group and both CHX and Diode laser groups (*p* \u0026lt;0.001) for each comparison.No statistically significant difference was detected between the CHX and Diode laser groups where (*p* =0.950).The highest mean value was recorded in Er-YAG laser group, whereas the least mean value was observed in CHX group\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (3): The mean, standard deviation (SD) values of P of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"111%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e20.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e17.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e20.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e17.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e20.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e19.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.719ns\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp; \u0026nbsp;ns; non-significant (p\u0026gt;0.05)\u003c/p\u003e\n\u003col start=\"2\"\u003e\n \u003cli\u003e\u003cstrong\u003eRelation between different groups according to P percentage of change:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (4) and figure (10),\u003c/strong\u003e A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* \u0026lt; 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* \u0026lt; 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.050). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (4): The mean, standard deviation (SD) values of percentage of change of P of different groups\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"116%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage of change\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e16.09%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode Laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e14.29%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e3.76%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eII)\u003c/strong\u003e \u003cstrong\u003eCa/P ratio changes:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ei. Relation between Pre and Post treatment values among all groups:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (5) and figure (11),\u003c/strong\u003e A statistically significant difference was observed between the Pre and Post groups, with *p* \u0026lt; 0.001. The highest mean value was recorded in the Pre group, whereas the lowest mean value was observed in the Post group\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRelation between different groups according to Ca/P ratio changes:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs presented in \u003cstrong\u003etable (5) and figure (11),\u003c/strong\u003e there was no statistically significant difference observed \u0026nbsp;between CHX group, \u0026nbsp;Diode laser group and Er-YAG laser group \u0026nbsp;where (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.785) in the pretreatment values of Ca/P ratio which means that the Ca/P ratio was standardized.\u003c/p\u003e\n\u003cp\u003eStatistically significant difference was observed between the CHX, Diode laser and Er-YAG laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.030).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was detected between Er-YAG laser group and each of CHX and Diode laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.040) and (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.043).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNo statistically significant difference was detected between CHX l group and Diode laser group (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.996).The highest mean value was recorded in Er-YAG lase group, while the lowest mean value was observed in CHX group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (5): The mean, standard deviation (SD) values of Ca/P ratio of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"111%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa/P ratio\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e2.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e2.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e2.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e2.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e2.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e2.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 32px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.785ns\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; 0.030*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp; \u0026nbsp;ns; non-significant (p\u0026gt;0.05)\u0026nbsp;\u003c/p\u003e\n\u003col start=\"2\"\u003e\n \u003cli\u003e\u003cstrong\u003eRelation between different groups according to Ca/ P ratio percentage of change:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eAs shown in \u003cstrong\u003etable (6) and figure (12),\u003c/strong\u003e A statistically significant difference was observed among the CHX, Diode laser, and Er:YAG laser groups (*p* \u0026lt; 0.001). Pairwise comparisons revealed significant differences between the Er:YAG laser group and both the CHX and Diode laser groups (*p* \u0026lt; 0.001 for each). No statistically significant difference was detected between the CHX and Diode laser groups (*p* = 0.712). The highest mean value was recorded in the CHX group, whereas the lowest mean value was observed in the Er:YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (6): The mean, standard deviation (SD) values of percentage of change of Ca/P of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"116%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa/P\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ePercentage of change\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e13.14%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode Laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e12.38%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 30px;\"\u003e\n \u003cp\u003e7.55%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 29px;\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 59px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05) \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3) Microleakage Assessment via SEM:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMicroleakage results were summarized in \u003cstrong\u003etable (7) and Figure (13).\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigures (14, 15, 16 and 17)\u003c/strong\u003e Illustrate SEM images of dye penetration along the tooth-restoration interface.\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003e\u003cstrong\u003eAt occlusal margin of the cavity:\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eA Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001). \u0026nbsp;Comparisons revealed significant differences between the Control group and both of Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001), meanwhile no statistically significant difference was observed between the Control and CHX groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.999).\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was observed between the CHX group and each of Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlso, a statistically significant difference was observed between the Er-YAG laser and Diode laser groups \u0026nbsp; (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e=0.006).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe highest mean value was recorded in the Control, group whereas the lowest mean value was observed in the Er-YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2-At gingival margin of the cavity:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups \u0026nbsp; (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001). Comparisons revealed significant differences between the Control group and each of CHX, Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001),\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was observed detected CHX group and each of Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u003c/em\u003e\u0026lt;0.001) and (\u003cem\u003e*p*\u003c/em\u003e=0.008).\u003c/p\u003e\n\u003cp\u003eAlso, a statistically significant difference was observed between Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u003c/em\u003e\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe highest mean value was recorded in the Control group whereas the lowest mean value was observed in the Er-YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3-Average of microleakage both occlusally and gingivally:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA Statistically significant difference was observed among the Control, CHX, Diode laser and Er-YAG laser groups \u0026nbsp; (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eComparisons revealed significant differences between the Control group and each of CHX, Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u003c/em\u003e\u0026lt;0.001).\u003c/p\u003e\n\u003cp\u003eA statistically significant difference was detected between the CHX group and each of Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u0026nbsp;\u003c/em\u003e\u0026lt;0.001).\u003c/p\u003e\n\u003cp\u003eAlso, a statistically significant difference was found between Er-YAG laser and Diode laser groups (\u003cem\u003e*p*\u003c/em\u003e\u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe highest mean value was recorded in the Control group whereas the lowest mean value was observed in the Er-YAG laser group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (7): The mean, standard deviation (SD) values of microleakage of different groups.\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"105%\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 81px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMicroleakage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOcclusal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGingival\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAverage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e15.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e11.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCHX\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e7.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e1.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e6.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e7.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiode laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e4.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e1.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e5.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e5.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.79\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEr-YAG laser\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003e3.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14px;\"\u003e\n \u003cp\u003e0.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e1.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e2.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13px;\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep-value\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 27px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026lt;0.001*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*; significant (p\u0026lt;0.05)\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eContemporary caries removal techniques do not reliably eradicate all microorganisms from the prepared cavity. Several studies have shown that bacteria may persist within the dentin even following the application of caries detector dyes. Furthermore, research indicates that fermentative microorganisms can survive beneath restorations lacking antiseptic properties for up to 139 days. Consequently, the incorporation of cavity disinfection as an adjunct to conventional caries removal procedures is recommended to eliminate residual microbial contamination. This approach may help reduce the risk of secondary caries, postoperative pulp sensitivity, and pulpal inflammation prior to definitive restoration [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe infiltration of Bacterial cells, nutrient compounds, or hydrogen ions derived from dental plaque into the interface between the tooth and restorative material can result in complications such as marginal discoloration, fractures, secondary caries, corrosion, sensitivity, and pulpal inflammation [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eNumerous studies have advocated for various cavity disinfection methods, encompassing chemical agents, lasers, ozone therapy, and other modalities [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eChlorhexidine digluconate (CHX) is a potent antimicrobial agent recognized for its effective inhibition of streptococcal growth, rendering it a promising candidate for the prevention of dental caries. Upon application to dentin surfaces, CHX exerts a prolonged antibacterial effect by the sustained release of positively charged molecules, a phenomenon known as substantive antimicrobial activity (SAA) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e2% concentration of chlorhexidine digluconate (CHX) was employed in this study due to its widespread use in both clinical dentistry and research. This aqueous formulation is generally considered biocompatible and exhibits an acceptable toxicological profile, rendering it a reliable and effective choice for cavity disinfection [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlthough CHX has a widely proven effect Haralur et al., found that it has a negative effect on dentine regarding Ca content and hardness [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] also it negatively impacts the bonding and sealing of adhesive restorations to dentin, potentially leading to increased microleakage [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eLaser has been widely used as an efficient dental cavity disinfectant; it has a potent antibacterial effect with avoidance of the side effects of using chemicals and it has some positive effects on dentine such as removal of smear layer which consequently leads to improvement of bonding between dentine and restoration [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, and \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThe interaction between the laser and tissue is greatly influenced by the laser's wavelength and the power density applied [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDiode lasers are available in four main wavelengths: 810\u0026ndash;830 nm, 940 nm, 980 nm, and 1064 nm. Their antibacterial effectiveness is largely attributed to the thermal effects and the corresponding rise in temperature generated during irradiation. Diode laser 980 nm was chosen in our study because of its potent antibacterial efficacy beside its ability to remove the smear layer [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eLow-energy Er:YAG laser treatment modifies the dentin surface by efficiently removing debris and exposing open dentinal tubules. Researches indicated that the heat generated by the Er:YAG laser can neutralize free radicals and alter the dentin surface, thereby enhancing its suitability for bonding [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOperating at a wavelength of 2.94 \u0026micro;m, the Er:YAG laser has demonstrated bactericidal effects against Streptococcus mutans. In this study, a low energy output of 1.2 watts was utilized to minimize thermal damage to dentin and avoid potential reductions in dentin hardness. This parameter selection is supported by Du et al., who found that power settings between 1 and 1.5 watts effectively reduce S. mutans levels without compromising dentin integrity [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eScanning electron microscopy (SEM) was employed in this study to evaluate the ultrastructural changes on the dentin surface following the application of the tested treatments, owing to its capability to provide both qualitative and quantitative assessment of morphological features [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eScanning electron microscopy analysis of dentin treated with 2% chlorhexidine demonstrated irregular dentinal tubules characterized by partial occlusion and the presence of residual smear layer. The findings corroborate those presented in prior research by Lapinska et al. [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], who observed multiple and singular deposits irregularly distributed across the dentine surface, located both within pits created by mechanical preparation and on the smooth areas of the sample. Similarly, Siwnata et al. [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] reported that 2% chlorhexidine gluconate was insufficient for complete removal of the smear layer during cavity cleansing, resulting in the persistence of smear plugs that impeded the full opening of dentinal tubules.\u003c/p\u003e\u003cp\u003eIn the present study, dentin treated with diode laser at a power setting of 1 W exhibited an irregular surface with an apparent opening of dentinal tubules with partial removal of smear layer. Our findings are in line with prior research outcomes by Behniafar et al., who also observed that the application of a diode laser at 1 W power output and a wavelength of 980 nm did not result in a significant increase in pulpal temperature or cause structural damage such as fissures or cracks on the dentin surface with partial removal of smear layer [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThese outcomes contradict earlier reported data of Jhingan et al. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] and El Tayeba et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] who stated that total smear layer and debris removal, accompanied by morphological changes such as dentin melting, these findings may be attributed to the higher power used in their study as both of them employed diode laser at 2 W and 1.5 respectively.\u003c/p\u003e\u003cp\u003eAnother study conducted by Abdou et al. [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] achieved effective smear layer removal and complete opening of dentinal tubules using a diode laser at 1.5 W. although the previously used parameters produced an efficient smear layer removal but they may produce harmful effects on the pulp according to Jaine et al who found that both 1 W and 2W had similar antibacterial effects when used for dentine disinfection but found that 1 W was safer than 2 W for the pulp which produced higher temperature rise of the pulp [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn our study dentine surface treated with erbium yag laser showed an obvious widening of dentinal tubules with total removal of smear layer. These findings were in alignment with Vieira et al., and Wang et al., who reported that dentin surfaces treated with Erbium:YAG laser exhibited open dentinal tubules and were free of smear layer, resulting in a retentive surface pattern that can improve bonding to dentin [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eA study conducted by found Burlat et al. hat using Er:YAG laser with a power range between 250\u0026ndash;300 mj led to surface cracks and disintegration of dentine but these findings may be the result of the high laser power used in his study, this was in agreement with another study conducted by Wanderley et al., [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eCalcium (Ca) and phosphorus (P), which are found in hydroxyapatite crystals, make up the primary inorganic components of dental hard tissues. Changes in the Ca/P ratio can disrupt the natural balance between the organic and inorganic components, possibly altering the structural properties of dentin, including its permeability and solubility. [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn our study, Edx was used to the change in mineral content of dentine after different disinfection modalities, it was chosen because of its accuracy and sensitivity in measuring mineral content [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eEDX values of Ca and P of all experimental groups exhibited lower Ca/P weight ratios compared to their control (untreated) samples.\u003c/p\u003e\u003cp\u003eThe observed decrease in calcium and phosphorus levels following chlorhexidine (CHX) application aligns with the findings reported by Haralur et al. and Kimyai et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This decrease Can be ascribed to the cationic nature of CHX, which enables it to bind readily to anionic molecules, such as the phosphate groups present in hydroxyapatite resulting in the displacement and subsequent release of calcium ions (Ca) from dentin ;these findings suggest that CHX may contribute to calcium ion removal through its interaction with phosphate [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eRegarding diode laser Statistical analysis indicated a significant difference between values recorded before and after treatment regarding calcium and phosphorous content, this was in accordance with Azmy et al who found that diode laser as a surface treatment resulted in observable changes in the mineral content of radicular dentin [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn contrast with our findings, Abdou et al, claimed that no chemical changes in dentin components following diode laser application. These results may be attributed to the use of distilled water as an irrigant immediately before the application of the 980 nm diode laser on the dentin surface which may lead to absorbance of heat produced by the photothermal effect of diode laser thereby preserving the inorganic content of the dentin without causing any alteration in the mineral content [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eEr:YAG laser treatment resulted in the smallest percentage change in calcium and phosphorus content. These findings are consistent with those of Soares et al. [47], who reported that Er:YAG laser irradiation at an energy setting of 100 mJ caused only minimal alterations in the elemental composition of the treated surface, along with a slight reduction in the calcium-to-phosphorus (Ca/P) ratio.\u003c/p\u003e\u003cp\u003eOn the contrary, Moosavi [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] has reported that Er:YAG laser irradiation led to an increase in microhardness and calcium ion content in dentine; however, these differences were not statistically significant when compared to their respective control groups.\u003c/p\u003e\u003cp\u003eMicroleakage is defined as the infiltration of oral fluids, molecules, bacteria, and ions at the interface between the cavity walls and the restorative material. Preventing microleakage is crucial for ensuring the longevity and clinical success of dental restorations. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAs a matter of fact, an ideal cavity disinfectant should offer effective antimicrobial activity while maintaining the sealing integrity of restorative materials. Compromising this seal can lead to marginal leakage, which may reduce the longevity of the restoration by allowing bacteria and fluids to infiltrate the interface between the tooth and the restorative material [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMicroleakage can be evaluated using various techniques, among these, dye penetration technique which was used in our study, is one of the most commonly used methods in recent research due to its practicality\u0026mdash;dye solutions are readily available, the method does not involve reactive chemicals or radiation, and it is both highly feasible and easily reproducible. [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThermal cycling is widely employed in in vitro studies. This technique is particularly valuable in microleakage research, as it effectively simulates the clinical aging process of dental restorations in the oral cavity. In the present study, all specimens in our study were subjected to 5,000 thermal cycles between 5\u0026deg;C and 55\u0026deg;C prior to microleakage assessment [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThe group treated with chlorhexidine exhibited a lower level of microleakage at the tooth\u0026ndash;restoration interface when compared to control group. These findings are consistent with the studies conducted by Ramezanian et al., [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] which reported that chlorhexidine significantly reduces microleakage both immediately following restoration and over time. Similarly, a review by Satpute highlighted chlorhexidine\u0026rsquo;s role in enhancing the longevity of restorative materials [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eHowever, The study outcomes disagree with a study by Mutluay et al. who reported that chlorhexidine had no significant effect on microleakage compared to the control group. This discrepancy may be attributed to differences in experimental protocols, particularly the duration of chlorhexidine application and the type of restorative material used; their study employed a giomer-based restoration, whereas composite resin was used in the present study [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn our study, diode laser 980 nm group exhibited a lower microleakage value when compared with control and chlorohexidine groups. These findings were consistent with of El Mansy et al., who reported that the use of a 980 nm diode same power and time laser resulted in the lowest statistically significant microleakage levels when compared to CHX and control groups. In contrast, Ipek et al. found no significant improvement in microleakage following diode laser treatment, this discrepancy may be attributed to variations in laser parameters used across studies which are employing a different application time and utilizing a different restorative material [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn relation to the Er:YAG laser, our results indicated that it produced the lowest levels of microleakage among all groups tested\u003c/p\u003e\u003cp\u003eA study by Emilie Luong and Amir Shayegan demonstrated that Er:YAG laser conditioning of enamel and dentin surfaces beneath resin composite has a great potential to reduce microleakage [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eA study by Sharafeddin and Tabrizi found that the Er:YAG laser had a favorable effect in reducing microleakage at both occlusal and gingival margins when compared to CO2 laser [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Similarly, a study conducted by Ipek Aslan et al. found that the Er,Cr:YSGG laser group demonstrated superior performance in reducing nanoleakage compared to the diode laser and chlorhexidine groups. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e. According to our knowledge, there is no previous study that compared Er:YAG laser with diode laser or chlorohexidine for cavity disinfection or compared between their effect on the morphology of dentine.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWithin the limitations of this study, it can be concluded that the Erbium:YAG laser demonstrated the most favorable outcomes in terms of preserving and enhancing both the morphological and chemical composition of dentin. Moreover, it resulted in the lowest microleakage values among all tested groups, indicating superior sealing ability and potential for long-term restoration success.\u003c/p\u003e\u003cp\u003eBoth the diode laser and 2% chlorhexidine (CHX) showed beneficial effects compared to the control, with no significant difference between them\u003c/p\u003e\u003cp\u003eCHX exhibited the highest microleakage values, suggesting a less favorable impact on the marginal integrity of restorations.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompeting interests:\u003c/h2\u003e\u003cp\u003eThe authors declare no conflicts of interest related to this study.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eThis research was conducted without external funding and was entirely self-financed by the authors\u003c/p\u003e\u003ch2\u003eAvailability of data and materials:\u003c/h2\u003e\u003cp\u003eThe datasets generated and/or analyzed during the present study are available from the corresponding author upon reasonable request. 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Assessment of microleakage of Class V restored by resin composite and resin-modified glass ionomer and pit and fissure resin-based sealants following Er:YAG laser conditioning and acid etching: in vitro study. Clin Cosmet Investig Dent. 2018;10:83\u0026ndash;92. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2147/CCIDE.S153989\u003c/span\u003e\u003cspan address=\"10.2147/CCIDE.S153989\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":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":"bdj-open","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"bdjopen","sideBox":"Learn more about [BDJ Open](http://www.nature.com/bdjopen/)","snPcode":"41405","submissionUrl":"https://mts-bdjopen.nature.com/cgi-bin/main.plex","title":"BDJ Open","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Erbium:YAG laser, diode laser, chlorhexidine, dentin morphology, mineral content, microleakage, cavity disinfection, composite restoration","lastPublishedDoi":"10.21203/rs.3.rs-7345490/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7345490/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResidual microorganisms may remain even after thorough mechanical cavity preparation, leading to secondary caries. Additionally, the smear layer generated during this process can impair the adhesion between composite resin and dentine and limit the penetration of disinfectants into dentinal tubules. This study aimed to compare the effects of 2% chlorhexidine (CHX), 980 nm diode laser, and Er:YAG laser as cavity disinfectants on dentine morphology, mineral content, and microleakage of composite restorations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eForty extracted sound human primary molars were randomly assigned to four groups (n = 10): Group I (negative control, no disinfection), Group II (2% CHX application), Group III (980 nm diode laser, 1 W, continuous wave), and Group IV (Er:YAG laser, 1.2 W). Dentine morphology and restoration microleakage were examined via Scanning Electron Microscopy: (SEM), while mineral content was evaluated using Energy-Dispersive X-ray Spectroscopy (EDX).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSEM analysis showed that CHX (Group II) left smear layer residues with narrowed tubules, while the diode laser (Group III) partially removed the smear layer. Er:YAG laser (Group IV) resulted in complete smear layer removal, wider tubules. EDX revealed significantly higher mineral content in Group IV compared to Groups II and group III (p \u0026lt; 0.001), with no significant difference between Groups II and III. Microleakage was highest in the control group and lowest in the Er:YAG group (p \u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Er:YAG laser showed superior outcomes in improving dentine morphology, increasing mineral content, and minimizing microleakage, making it the most effective disinfectant tested.\u003c/p\u003e","manuscriptTitle":"The effect of Chlorohexidine, Er:YAG Laser and Diode Laser 980 nm as Dental Cavity Disinfectants on Dentine Morphology and Microleakage of Composite Restoration: An In Vitro Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-11 15:38:36","doi":"10.21203/rs.3.rs-7345490/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"revise","date":"2025-08-27T09:13:07+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-21T08:57:41+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-11T10:40:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"BDJ Open","date":"2025-08-11T10:40:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bdj-open","isNatureJournal":false,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"bdjopen","sideBox":"Learn more about [BDJ Open](http://www.nature.com/bdjopen/)","snPcode":"41405","submissionUrl":"https://mts-bdjopen.nature.com/cgi-bin/main.plex","title":"BDJ Open","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b42d3b8c-f9bc-4d22-8a86-c8a722d536bd","owner":[],"postedDate":"September 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":53773105,"name":"Health sciences/Health care/Dentistry"},{"id":53773106,"name":"Health sciences/Health care/Dentistry/Paediatric dentistry"}],"tags":[],"updatedAt":"2026-01-16T11:15:54+00:00","versionOfRecord":{"articleIdentity":"rs-7345490","link":"https://doi.org/10.1038/s41405-025-00391-z","journal":{"identity":"bdj-open","isVorOnly":false,"title":"BDJ Open"},"publishedOn":"2026-01-15 05:00:00","publishedOnDateReadable":"January 15th, 2026"},"versionCreatedAt":"2025-09-11 15:38:36","video":"","vorDoi":"10.1038/s41405-025-00391-z","vorDoiUrl":"https://doi.org/10.1038/s41405-025-00391-z","workflowStages":[]},"version":"v1","identity":"rs-7345490","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7345490","identity":"rs-7345490","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}