OBJECTIVE:In cases of failed root canal treatment, rotary NiTi files enhance retreatment efficiency by facilitating effective removal of root canal filling materials while minimising procedural errors and preserving canal anatomy. To compare the efficiency of ProTaper Ultimate (PTUL) and ProTaper Gold (PTG) in the retreatment of root canals previously obturated with AH Plus or TotalFill Bioceramic sealer. METHODS:Sixty extracted single-rooted teeth were prepared using the Reciproc R40 and then divided into 4 groups (n = 15) according to the sealer used; AH Plus or TotalFill Bioceramic, and the retreatment file system, PTUL or PTG. The retreatment time was recorded, and the percentage of the residual filling material was assessed using a stereomicroscope. Statistical analysis was performed at a significance level of P < .05. RESULTS:A significant interaction was observed between sealer type and retreatment file system for both retreatment time and the percentage of remaining filling material (P < .05). Overall, retreatment of TotalFill Bioceramic was significantly faster than AH Plus. Within the AH Plus groups, the PTG system was significantly faster than PTUL, whereas no time difference was noted between files for the TotalFill groups. Regarding filling material removal, the PTUL was significantly more effective at removing TotalFill Bioceramic compared to PTG, which left the highest amount of residual filling material. Conversely, both file systems demonstrated statistically similar efficacy in removing the AH Plus sealer. CONCLUSION:The optimal retreatment file system is heavily sealer-dependent; PTUL maximises the removal of TotalFill Bioceramic, whereas PTG expedites the removal of AH Plus without compromising cleanliness.

OBJECTIVE:To evaluate the effectiveness of three rotary file systems on the elimination of Enterococcus faecalis (E. faecalis) biofilms in single-rooted teeth. METHODS:A total of 70 mandibular premolars were included in this study in which 60 root canals were inoculated with E. faecalis. The positive control group (n=5) received bacterial inoculation without mechanical preparation. The negative control group (n=5) was neither infected nor mechanically prepared. The teeth were randomly assigned to 3 experimental groups (n=20 per-group) according to application of the rotary files: Group 1: XP-endo Rise Shaper (FKG, Le Crêt-du-Locle, Switzerland); Group 2: XP-endo Shaper (FKG, Le Crêt-du-Locle, Switzerland); Group 3: ProTaper Gold (Dentsply Sirona, Erlangen, Germany). Samples were collected using paper points before (S1) and after (S2) mechanical preparation. Colony-forming units (CFUs) were used to quantify bacterial loads. RESULTS:Significant differences in bacterial counts were observed from S1 to S2 in all tested groups (p<0.001). Intergroup comparisons revealed no significant differences between the XP-endo Rise Shaper and XP-endo Shaper groups (p>0.05) and between XP-endo Shaper and ProTaper Gold groups (p>0.05). Significant differences were observed between the XP-endo Rise Shaper and ProTaper Gold groups (p<0.05). The XP-endo Rise shaper group showed the largest reduction in bacterial loads (98.2%), followed by the XP-endo Shaper (96.0%) and ProTaper Gold (93.8%) groups. CONCLUSION:All tested rotary files were able to reduce bacteria but the novel single-file system (XP-endo Rise shaper) was superior in reducing bacterial load compared to XP-endo Shaper and the multiple file system (ProTaper Gold). (EEJ-2024-08-133).

Objectives:To evaluate the effect of angle of access and kinematics on the dynamic cyclic fatigue resistance of E3 Azure rotary NiTi files at body temperature. Methods:Eighty E3 Azure files, 25/06, were randomly divided into two equal groups according to the kinematics used, rotation, and reciprocation. Each group was further divided into two equal subgroups (n = 20) according to the angle of file access, zero degrees and 30 degrees. The files were placed in custom-made stainless-steel canals and operated using the manufacturer's recommendations for speed, torque, and angle of reciprocation settings till fracture. The time to fracture and the fracture length were measured. Statistical analysis was performed at a significance of 0.05. Results:Samples instrumented using reciprocation motion had significantly higher time to fracture than those with continuous rotation (p < 0.001). Samples with zero-degree access angle had significantly higher time to fracture than those with 30° (p < 0.001). Conclusion:The motion and the angle of file access significantly influence the cyclic fatigue resistance of E3 Azure files. Reciprocation motion and a smaller angle of access improve the fatigue resistance of E3 Azure files. Clinical relevance:Reciprocation motion and establishment of straight-line access enhance the safety and efficiency of E3 Azure files.

To evaluate the impact of cooling the anesthetic solution prior to administering intra-pulpal anesthesia on the severity of intraoperative pain during root canal treatment in mandibular molars with symptomatic irreversible pulpitis and symptomatic apical periodontitis. Forty patients with mandibular molars diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis received root canal treatment by a single operator following a standardized technique. Patients received an intra-pulpal injection of 2% lidocaine with 1:100,000 epinephrine and were randomly and equally assigned to two groups based on the temperature of the cartridge. The room-temperature group received a cartridge that was kept at 25-26 °C while for the cryoanesthesia group, the cartridge was cooled to a temperature of 4-5 °C. The HP-VAS scale was used to evaluate the patients' preoperative, intraoperative pre-injection, and intraoperative post-injection pain scores. The success rate was calculated by the lack of additional anesthesia following the intra-pulpal injection. Pain scores were statistically analyzed at a significance level of 0.05. Both the cryoanesthesia and the room-temperature groups were effective in significantly reducing the severity of intraoperative pain, where p < 0.001 for both groups. The cryoanesthesia group showed a 100% success rate compared to 80% for the room-temperature group without a statistically significant difference (p = 0.106). The difference in pain score reduction in both groups, however, was statistically significant (p < 0.001). Cryoanesthesia yielded more profound pulpal anesthesia compared to the room temperature intra-pulpal injection.

Objective: To assess the extruded debris apically by the ProTaper Ultimate rotary nickel-titanium files compared to the ProTaper Gold files on preparing the mesiobuccal root canals of mandibular molars. Methods: Thirty mandibular molars with mesial canals showing Vertucci Type-IV configuration and curvatures ranging between 20° to 40° were selected and divided into two groups per the rotary files used for root canal shaping (n=15). Myers and Montgomery's methodology was adopted for the collection of debris. The average weight of the collected dried debris was recorded and statistically analyzed using the independent t-test at a significance level of (p<0.05) after log transformation. Results: The ProTaper Ultimate showed significantly less debris extruded (2.35+-0.65 mg) than ProTaper Gold (3.25+-0.47 mg) (p=0.001). Conclusion: ProTaper Ultimate can efficiently prepare curved root canals with the minimal amount of apical debris extruded compared to ProTaper Gold. (EEJ-2024-06-100)

Abstract Purpose This research aimed to investigate fracture resistance of endodontically treated maxillary premolars restored using preheated thermo-viscous and fiber-reinforced bulk fill resin composite, in vitro. Methodology Sixty sound human maxillary premolars were selected and divided randomly into 6 groups of ten teeth each (n = 10). Group 1; is the positive control with sound unprepared teeth (P), Group 2; is the negative control in which Mesio-occluso-distal (MOD) cavities were left unrestored (N), Group 3; includes the teeth restored by incremental packing with conventional nanohybrid composite (ChP), Group 4; includes teeth restored with short fiber reinforced bulk fill composite (EF), Group 5; includes teeth restored with preheated thermo-viscous bulk fill composite (VB), and Group 6; includes teeth restored using packable bulk fill composite (XF) Tested restorative materials were bonded with a universal adhesive in self-etch mode. Teeth were kept in distilled water for 24 h at 37 °C proceeded by thermocycling (5- 55 °C, 1200×). Teeth were then exposed to compressive load till fracture at a crosshead speed of 1 mm/min. One-way ANOVA followed by Tukey post-hoc test was implemented to compare between more than two groups in non-related samples. The significance level was established at α = 0.05 for both tests. Results Intact teeth significantly recorded the highest fracture resistance values among all groups. A significant difference was recorded among all the tested groups, with the EF recording the highest values, followed by the VB group then the XF group and ChP that recorded the lowest data. Negative control premolars significantly recorded the lowest fracture. Conclusions After thermocycling, endodontically treated maxillary premolars restored with pre-heated thermos-viscous composite did not exhibit an increase in fracture resistance. Notably, our findings indicate that short fiber-reinforced composite demonstrated significantly higher fracture resistance compared to other types of composites assessed in this study. This suggests the potential superiority of short fiber-reinforced composite in enhancing the overall structural integrity of endodontically treated teeth subjected to occlusal forces.

Aim: Evaluation of the antibacterial and cytotoxic properties of TotalFill and NeoSEALER Flo bioceramic sealers compared to AH Plus resin sealer. Materials and Methods: Modified direct contact test was used on three sets of sealers: Freshly mixed sealers, sealers that were 1-day old, and sealers that were 7-day old. After 24 h of incubation, the colony-forming units were digitally counted using Promega Colony Counter after 30 and 60 min of exposure to Enterococcus faecalis. For cytotoxic effect evaluation, 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assay was performed at three different time points: 24 h, 48 h, and 120 h after adding the sealer eluates to human gingival fibroblasts, to assess cell viability. Data were analyzed using mixed model analysis of variance followed by post hoc test. Results: TotalFill bioceramic sealer showed the highest bacterial reduction against E. faecalis throughout all intervals. AH Plus showed great antibacterial activity initially which reduced drastically after 7 days. All the sealers showed a reduction in their antibacterial activity with time. TotalFill and NeoSEALER Flo showed very high cell viability in contrast to AH Plus. Conclusion: TotalFill and NeoSEALER Flo demonstrate superior antimicrobial properties against E. faecalis which reduces with time. TotalFill and NeoSEALER Flo demonstrate acceptable biocompatibility against human gingival fibroblasts, which decreased over time.

Introduction: Bioceramic (BC) sealers exhibit multiple desirable biologic and physical properties. The aim of this study was to evaluate the effect of root canal moisture on the depth of TotalFill BC sealer penetration into dentinal tubules at different levels using a confocal laser scanning microscope (CLSM). Materials and Methods: The manuscript of this laboratory study has been written according to preferred reporting items for laboratory studies in endodontology 2021 guidelines. Forty single-rooted extracted human premolars were decoronated using a low-speed diamond disc, followed by root canal preparation using nickel–titanium files under copious irrigation. The samples were randomly allocated for obturation into four groups n = 10 based on the sealer and root canal moisture status. Group A: TotalFill BC sealer in wet canal, Group B: TotalFill BC sealer in dry canal, Group C: AH Plus sealer in wet canal, and Group D: AH Plus sealer in dry canal. The roots were sectioned at three different distances from the apex. The root segments were examined using CLSM to measure the extent of sealer penetration into the dentinal tubules. The data underwent analysis through a three-way mixed ANOVA test, followed by post hoc assessments (P < 0.05). Results: In wet canals, the tubular penetration of TotalFill BC sealer was notably greater than that of AH plus, with a statistically significant difference. However, AH Plus sealer had a statistically significant tubular penetration in the dry canals compared to the wet. Greater sealer penetration was observed at 5 mm from the apex, followed by 3 mm, and the least penetration depth was found at 1 mm from the apex. Conclusions: The presence of root canal moisture and distance from the apex had a significant impact on the penetration of TotalFill BC sealer into the dentinal tubules.

Objectives This study aimed to compare the intensity of postoperative pain following the final rinse using cold saline compared with room temperature saline and occlusal reduction. Materials and Methods A prospective, parallel, double-blinded randomized controlled trial was conducted on 69 first mandibular molars diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis. Single-visit root canal treatment was performed; access cavity preparations and chemomechanical preparations were carried out using the ProTaper Gold rotary system under copious irrigation using 3% sodium hypochlorite and 17% EDTA. The patients were divided into three groups ( n = 23): control group: room temperature saline (25 degrees C) final rinse without occlusal reduction; cryotherapy group: cold saline (2.5-4 degrees C) final rinse without occlusal reduction; and occlusal reduction group: room temperature saline with occlusal reduction. Pain scores were recorded using the visual analog scale preoperatively and postoperatively via telephone at 6, 24, 48, 72 hours, and 7 days intervals. Age data were analyzed using one-way analysis of variance followed by Tukey's post hoc test. Pain score data were analyzed using Kruskal-Wallis' test followed by Dunn's post hoc test for intergroup comparisons and Friedman's test followed by Nemenyi's post hoc test for intragroup comparisons. Correlations were analyzed using Spearman's rank-order correlation coefficient. The significance level was set at p < 0.05 within all tests. Results Cryotherapy reduced postoperative pain compared with the control group with a statistically significant difference at 24 hours only ( p = 0.016). At other intervals, no statistically significant difference in pain score was measured between all three groups ( p > 0.05). After 7 days, all patients recorded a zero pain score. Conclusion Cryotherapy was as effective as the occlusal reduction in reducing postoperative pain in cases of symptomatic irreversible pulpitis with symptomatic apical periodontitis, significantly more than the control group.

Aim: To describe the management of a maxillary first molar with six root canals, two in each root. Summary: A 36-year-old male patient presented with a complaint of discoloration and decay on an upper left back tooth. Clinical examination revealed the presence of deep occlusal caries on the maxillary left first molar. A detailed clinical and radiographical examination led to a diagnosis of pulp necrosis with asymptomatic apical periodontitis. Non-surgical root canal treatment was performed. Due to the suspected anatomical variation, Cone beam computed tomography (CBCT) imaging was obtained. CBCT imaging and clinical identification using the DOM revealed the presence of six root canals, two in each root, with the code (326 MB2 DB2 P2-1) using Ahmed et al. system. Root canal treatment was successfully performed and confirmed radiographically. The tooth was restored with a resin composite restoration. Key Learning Points: center dot This case highlights how clinicians must approach root canal treatment with a com-prehensive mindset that considers the potential for extraordinary anatomical complexities. center dot Preoperative knowledge of root canal anatomy and proper armamentarium are mandatory for successful root canal treatment procedures.

Objective: The aim of this study was to evaluate the effect of different glide path files on the amount of apically extruded debris. Material and Methods: Sixty single-canaled mandibular premolars were accessed and randomly divided into three groups (n= 20) according to the file used for glid path creation; group A using Traverse file, group B using WaveOne Gold Glider, group C using stainless steel K file. All teeth were then instrumented using the Reciproc system. The debris extruded apically during instrumentation were collected into pre-weighed Eppendorf tubes which were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weights of the Eppendorf tubes. The data were analyzed using one-way ANOVA test, and post hoc analysis. Results: WaveOne Gold Glider produced the least amount of apical extruded debris (0.41±0.25) followed by the Traverse group (0.59±0.20) then the K-file group (0.64±0.16) with a statistically significant difference (p=0.003). Conclusion: Apical extrusion of debris is inevitable during root canal cleaning and shaping. Creation of glide path using engine-driven files produces less amount of apically extruded debris compared to hand-driven K-files. KEYWORDS Root canal preparation; Nickel titanium alloy; Dental instruments.

minor variations in an attempt to improve the original MTA's limitations.Produits Dentaires (PD) MTA White (Produits Dentaires SA, Vevey, Switzerland) is one of these formulations, which has been produced to be used for pulp capping, pulpotomy, apical plugs, and retrograde filling. 8iodentine (Septodont, Saint-Maur-des-Fossés, France) is another formulation that solved the problem of the prolonged IntroductIonProper cleaning and shaping, in addition to three-dimensional fluidtight sealing of the root canal system, are required for the success of the root canal treatment.Surgical endodontics is indicated to address some mishaps and pathologies that could not be managed using conventional orthograde nonsurgical root canal treatment. 1ollowing root-end resection and retrograde cavity preparation during periapical surgery, the cavity should be properly sealed in order to provide a favorable environment for the healing of the periradicular tissues.The retrograde filling material should therefore prevent bacterial leakage and provide a three-dimensional apical seal. 2,3 Retrograde filling materials should be biocompatible, insoluble, easily manipulated, and insensitive to moisture during application and setting.Amalgam, gutta-percha, intermediate restorative, super ethoxy benzoic acid, glass ionomer, and composites were previously used as retrograde filling materials, but they failed to demonstrate all of the desired properties. 4ineral trioxide aggregate cement (MTA) is a calcium silicatebased cement (CSC) developed at Loma Linda University in the mid-1990s. 5ProRoot MTA (Dentsply Sirona, York, USA) was the first commercial MTA launched in the market and was extensively studied and tested. 6Hence, it became the gold standard for retrograde filling materials owing to its superior biocompatibility, bioactivity, good sealing ability, and antimicrobial properties.Yet, ProRoot MTA has shown some limitations, such as the long setting time, discoloration, and poor handling properties. 7Recently, other brands/formulations of MTA have been developed in the market.These formulations share the same original formula, with some 1,

Abstract Aim This study compared the perceptions and exam performance of third-year undergraduates in endodontic courses. The study analyzed hybrid training during COVID-19 and Face-to-Face teaching post-COVID-19 to identify the most effective teaching methods. Materials and Methods This study was a single-centre retrospectively analyzed endodontic courses delivered to third-year dental students in 2021 and 2022 at the Gulf Medical University, College of Dentistry. Student perceptions of the hybrid and F2F courses were obtained through a satisfaction questionnaire administered by the University's Quality Assurance Office at the end of each course. Student performance was measured by analyzing exam grades for both teaching modes. Results Total of 75 students took the hybrid course while 77 received the F2F course. The number of respondents to the questionnaire was significantly higher for the F2F group (81% vs. 31.5%, p ≤ 0.05). The hybrid course received a satisfaction score of 100% compared to 94.54% for F2F. Student performance in the hybrid group was comparable to the F2F group, with mid- and end-of-year course marks ranging from 64.67% to 71.46% and 63.93% to 65.79%, respectively (p ≤ 0.05). These findings suggest that the hybrid model did not negatively affect student performance. Conclusion. In conclusion, the hybrid learning approach was well-received and produced similar endodontic exam marks to F2F teaching. This suggests that combining e-learning with F2F teaching can maintain the quality of education. The absence of differences between the groups dismisses concerns that endodontic education suffered due to the pandemic.

Background: Improper shade selection is one of the most common causes behind restorations’ remake and patient dissatisfaction. Multiple protocols and devices have been proposed to address the limitations of visual shade selection. Objective: To compare the accuracy of dental shade matching gathered visually with both VITA Classical (VC) and VITA 3D-Master (V3D) shade guides with those obtained instrumentally with both 3Shape Trios 3 and VITA Easyshade® Advance 4.0. Materials and Methods: For visual shade selection (VSS), one- hundred participants from King AbdulAziz University, Faculty of Dentistry participated in the study and asked to select the shade of six masked shade tabs from both VC [A1, A2, B1] and V3D [1M1, 2M3, 3R1.]. Later, Instrumental shade determination (ISD) was completed by one experienced participant for six cycles using: VEasy and Trios 3. Results: Significant difference was found between VSS and ISD. The results suggested that although participants significantly preferred VC over V3D in terms of VSS, this did not improve the shade selection performance. Besides, in ISD, no significant difference was reported between VEsay and Trios 3. There was no statistical significance difference between neither Trios 3 when combined with VC and V3D nor between VEasy when combined with VC and V3D. VEasy showed the best shade selection performance when combined with V3D, although the difference was non-significant. Conclusion: The result of the present study supports the promising use of the intra oral scanner 3Shape Trios 3 and dental spectrophotometer VITA Easyshade® Advance 4.0. Combination with a visual selection method may result in more accurate and reliable results.

INTRODUCTION:The aim of this study was to assess the dynamic cyclic fatigue resistance of an R-Motion file at simulated body temperature and document corresponding phase transformations compared to OneCurve and HyFlex EDM (HFEDM). METHODS:R-Motion (25/.06), OneCurve (25/.06), and HFEDM (25/.06) files were selected and divided into 3 groups (n = 9) according to the file type. Dynamic cyclic fatigue testing was done with a custom-made artificial stainless-steel canal that had a 90° angle of curvature and a 5-mm radius of curvature. Files were operated continuously at body temperature until fracture in the artificial canal. The time to fracture was calculated. Statistical analysis was performed, and significance was set at 5%. Phase transformation temperatures for 2 instruments of each group were analysed by differential scanning calorimetry (DSC) analysis. RESULTS:The highest mean time to fracture value was measured in the HFEDM group (277.84 ± 2.51), followed by the R-Motion group (115.09 ± 0.01), whilst the lowest value was found in the OneCurve group (44.28 ± 3.63). Post hoc pairwise comparisons were all statistically significant (P < .001). DSC heating curves show austinite start temperatures to be 33.94 °C and 43.32 °C and austinite finish temperatures to be 35.09 °C and 50 °C for R-Motion and HFEDM, respectively. DSC cooling curves show martensite start temperatures to be 27.54 °C and 44.52 °C and martensite finish temperatures to be 29.13 °C and 37.68 °C for R-Motion and HFEDM, respectively. DSC curves of OneCurve failed to demonstrate transformation temperatures within the tested heat range. CONCLUSIONS:Crystalline arrangement of Ni and Ti atoms within the NiTi alloys greatly affects the dynamic cyclic fatigue resistance of the file.

Aim: To investigate the efficacy of the XP-endo Finisher-R (XP-FR) and manual H-filing in enhancing the removal of Totalfill BC sealer from oval root canals. Methodology: Forty mandibular incisors were prepared using ProTaper Next up to file X3 then filled with warm vertical condensation using Totalfill BC sealer. The volume of the root canal filling post-obturation and the remaining volume post-retreatment using Mani NRT-GPR system were assessed using Micro-CT (mu-CT). The total volume in 3 mm was calculated from the cervical line till the root apex using the CT-an software. Specimens were randomly divided into two equal groups n=20 according to the supplementary approach of gutta percha removal used; where Group I: XP-FR was used for 1 min, and Group II: size 30 H-file was used in a filing motion for 1 min. Specimens were again scanned using mu-CT and the remaining gutta percha volume was calculated. Data were statistically analyzed using Wilcoxon, Man-Whitney, Friedman tests with significance level of 5%. Results: Significant reduction of the remining filling material was recorded post-retreatment with percentage of reduction of 63.34%, 78.53%, and 66.21% at the apical, middle, and coronal thirds respectively using Mani NRT-GPR system. Supplementary removal approaches significantly improved filling material removal (P<0.05). XP-FR removed significantly more filling material than manual H-filing with percentage of filling material reduction of 52.22%, 34.92%, and 40.60% compared to 21.89%, 18.43%, 31.72% in the apical, middle, and coronal thirds (Man-Whitney test, P<0.001). Conclusions: Rotary retreatment files failed to totally remove the root canal filling material. Supplementary methods have improved root canal filling material removal; where XP-FR significantly removed more filling than manual H-filing.

Background: The aim was to compare the push-out bond strength of calcium silicate-based sealer Total Fill BC Sealer with an epoxy resin-based sealer Adseal used in cold lateral and single cone obturation techniques. Materials and Methods: Forty-eight single-rooted teeth with completely formed apices were selected. Teeth were decoronated, and working length was determined. Instrumentation and irrigation were performed. The teeth were equally and randomly divided into four groups (n=12) according to the obturation technique and the root canal sealer used as follow; Group I: Root canals were obturated using gutta percha & Totalfill bioceramic sealer by using single cone technique single cone technique, Group II: Root canals were obturated using gutta percha lateral condensation technique & Totalfill bioceramic sealer, Group III: Root canals were obturated using gutta percha & Adseal sealer by using single cone technique, and Group IV: Root canals were obturated using gutta percha & Adseal sealer by using lateral condensation technique. Manipulation and application of the sealer was done according the manufacturer instructions. All teeth were stored in an incubator at 37 °C and 100% humidity for 1 week to allow complete setting of the root canal sealers. Each root was prepared for push-out test using universal testing machine with root slices of 2 mm thickness were obtained at 3, 7, 11 mm from apex representing (apical, middle, and coronal) respectively, and the push-out bond strength was calculated. Statistical analysis was performed using One-way ANOVA followed by Tukey post hoc t-test was used to compare between more than two groups in non-related samples. Results: The highest bond strength was found in Group II (Totalfill & cold lateral obturation technique) (P < 0.05) compared to other groups. The lowest bond strength was found in Group III (Adseal & single cone obturation technique). Conclusion: The push-out bond strength of Totalfill & Adseal root canal sealers with cold lateral obturation technique were highest followed by Totalfill& single cone technique and lowest bond strength was observed in Adseal & single cone on obturation technique. Higher push out bond strength values recorded in apical and middle thirds than coronal third.

Background: The main reason suggested for the failure of endodontically treated teeth after a long period of time of intraoral performance is the lack of perfect coronal seal together with the presence of nanoleakage. Therefore, this study was conducted to evaluate to what extent the difference between adhesive systems may affect the seal achieved between pulp chamber dentin and the overlying coronal restoration together with nanoleakage evaluation. Materials and methods: Two groups of root canal treated teeth were bonded with two types of adhesive systems (Total-etch and Self-Etch) and restored with nano-hybrid resin composite. All teeth were thermocycled (2,500 cycles, 5°C to 55°C, 20 seconds dwell time, and 5 seconds resting time). After thermocycling, teeth were sectioned into sticks of 1 mm2 (15 sticks obtained from each group) for microtensile bond strength testing (mTBS). From each group, a slab of 1 mm2 was obtained for micromorphological analysis to observe the quality of the resin-dentin interface by scanning electron microscope and to evaluate nanoleakage pattern through silver tracing as well. The collected data were expressed in MPa and analyzed by independent sample t-test.Results: Regarding bond strength testing, highly significant difference was recorded between both adhesive systems (p<0.05). Total etch adhesive group showed higher results compared to the Self Etch one. Besides, SEM observations showed that all specimens showed different patterns of nanoleakage regardless of the type of adhesive system used.Conclusions: Total etch adhesive system showed better results than self-etch adhesive one in achieving good seal to pulp chamber dentin in endodontically treated teeth after thermocycling.

Objectives: The aim of this study was to compare the amount of apically extruded debris andthe patterns of smear layer formation following the preparation of root canals in extracted humanteeth using ProTaper Next, Twisted file, and a reciprocating single-file system.Material and Methods: Forty-five freshly extracted human single-rooted maxillary incisorswere divided into 3 groups (n=15) then instrumented using Protaper Next, Twisted files, andReciproc. The extruded debris were collected in a pre-weighed Eppendorf tubes. The tubes werestored in an incubator at 70 °C for 2 days before weighing the dry debris using analytical balance.The debris weight was determined by subtracting the initial weight from the final weight. Rootsamples were splitted longitudinally into two halves by making grooves then root halves (cervical,middle and apical) thirds were examined using Environmental Scanning Electron MicroscopeESEM (FEI Quanta 250 FEG, Berlin, Germany) at ×1500 magnification. All the data were subjectedto statistical analysis using Chi-squared, Fisher`s Extract.Results: The three tested rotary nickel titanium files produced comparable amount of debrisextrusion and smear layer patterns covering the root canal dentin walls. Apical third showed theheaviest accumulation of smear layer.