The Impact of Multiple Autoclave Cycles on the Surface Roughness of Thermally Treated Nickel-Titanium Endodontic Files

In this study, we evaluate the surface roughness (SR) of three thermally treated nickel-titanium rotary instruments (i.e., TruNatomy [TN], ProTaper Gold [PTG], and EdgeTaper Platinum [ETP]) after impact testing with multiple autoclave sterilization cycles using scanning electron microscopy (SEM). Overall, 60 thermally treated files were sourced (i.e., 20 TN, 20 ETP, and 20 PTG files), and each group was divided into four equal subgroups of five files (n = 5). An unsterilized group was assigned as the pre-autoclaving group (Cycle 0), and the other three groups underwent various autoclave sterilization cycles (Cycles 1, 5, and 10). The roughness average (Ra), root mean square (Rq), and average maximum peak-to-valley height (Rz) values were evaluated using SEM and ImageJ software. The Shapiro-Wilk test, one-way analysis of variance, and post-hoc Tukey test were used to analyze the data. The statistical significance level was set at p<0.05. Before autoclaving, all instruments showed debris and SR but with no statistically significant differences existing between the groups. SR values decreased after one autoclaving cycle for all instruments. After five autoclave cycles, the Rz value of ETP was statistically higher compared with PTG and TN. After 10 autoclave cycles, the Ra and Rq values of TN were statistically higher compared with ETP and PTG. These results suggest that multiple autoclaving sterilization cycles influence the SR of TN, PTG, and ETP, with ETP showing higher levels of surface irregularities than PTG and TN.Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R162), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Conservative preparation of curved root canals using novel nickel-titanium instruments: influence of operator experience

Background: Nickel-titanium (NiTi) instrumentation systems allow predictable dental root canal treatment. Novel systems promoting conservative preparation are constantly introduced into the market. Therefore, this study aimed to explore how operator experience would influence the performance using a new system – Race Evo- in preparation of curved root canals. Methods: Three groups of participants, with no previous experience with Race Evo, were compared: Third-year dental students, general dental practitioners (GPs), and endodontists. Each participant was asked to prepare 3 simulated resin blocks. Preparation time, the occurrence of procedural errors, and canal deviation were measured. Results: Endodontists prepared the canals with significantly fewer procedural errors (p = 0.027), and in less time than students (p < 0.001) and GPs (p = 0.019). However, there was no significant difference in performance between undergraduate students and GPs. In fact, endodontists and students alike prepared the canal with less deviation compared to GPs (p = 0.006 and p = 0.002). Conclusion: Proficiency in instrumenting curved canals with a new conservative NiTi system was not influenced by experience related to that of the general dental practitioner, but required more specialized experience in root canal treatment. Regardless of experience level, a learning period was still necessary

Influence of Preclinical Training on Root Canal Treatment Technical Quality and Confidence Level of Undergraduate Dental Students

Objectives. The aim of this study was to investigate the influence of exposure to additional preclinical endodontic training on undergraduate students’ technical quality of root canal treatment and overall confidence levels in endodontics. Methods. Technical quality of root canal treatment performed clinically by fifth-year undergraduate students was evaluated and divided into two groups: Group 1, teeth treated by students who had attended both a preclinical endodontic block course and an elective preclinical course. Group 2: teeth treated by students who had not attended the elective preclinical course. All students were also invited to participate in a survey to rate their undergraduate endodontic training and confidence levels performing endodontic treatment. Statistical analysis of data was performed using Person chi-square test, Fisher Freeman Halton exact test, and t-test. A p-value <0.05 was considered statistically significant. Results. There was no significant difference between the two groups in overall obturation quality (p=0.619). However, more teeth treated by attendees were of adequate obturation length (p=0.015) and lacked procedural errors (p=0.004). Significantly more elective course attendees rated their undergraduate endodontic training as adequate (p=0.002), but there was no significant difference in the level of confidence between the attendees and the non-attendees. Conclusion. Within the limitations of this study, additional preclinical training showed minimal effect on overall quality of root canal treatment performed clinically by undergraduate students and did not enhance their confidence levels; however, it was associated with more satisfaction with their undergraduate endodontic education

Cyclic fatigue resistance of EdgeTaper Platinum, Protaper Gold, and TruNatomy Prime rotary files before and after autoclave sterilization

Background This in vitro investigation aimed to determine the influence of multiple autoclave cycles on the cyclic fatigue resistance of three heat-treated nickel-titanium (NiTi) files: EdgeTaper Platinum (ETP), ProTaper Gold (PTG), and TruNatomy Prime (TN). Materials Sixty NiTi files, twenty of each NiTi file type: ETP 25/.06, PTG 25/.08, and TN 26/.04 were randomly divided into four equal subgroups (n = 5). The files for the control group were left un-autoclaved. Different autoclave sterilization cycles (one, five, and ten) were used for the other three groups. The files were then placed in a metal canal block and rotated according to the manufacturer’s instructions until fracture. The length of the broken segment and the time taken for fracture were measured. The fractured surfaces were subsequently subjected to SEM imaging. The Kruskal-Wallis test was used to analyze the data, followed by Dunn-Bonferroni pairwise comparisons. Statistical significance was set at p < 0.05. Results ETP showed significantly greater resistance to cyclic fatigue than TN in all autoclave groups and PTG after five autoclave cycles (p = 0.014). Fatigue resistance was not affected by the number of autoclaving cycles, except for ETP. After the first and tenth autoclaving cycles, they required significantly more rotations to failure than the non-sterilized files (p = 0.039 and p = 0.021, respectively). The fractured segments of the ETP files in these two groups were also longer than those in the control group (p = 0.010). Conclusion The cyclic fatigue resistance of ETP was greater than that of TN in all tested conditions. Repeated autoclave cycles of sterilization improved the cyclic fatigue resistance of the ETP files only and did not affect the cyclic fatigue resistance of TN and PTG. However, the ETP files separated at a longer distance from the tip with increased autoclaving cycles

Effect of sodium hypochlorite temperature and concentration on the fracture resistance of root dentin

Abstract Background Sodium hypochlorite (NaOCl) is the most efficient root canal irrigant to date. The aim of this study was to compare the effect of NaOCl used at different temperatures and concentrations on the compressive strength of root dentin. Materials and methods Seventy-two extracted human single-canaled straight roots of comparable size and length were selected and randomly divided into six groups (n = 12): Group (A) served as a control with unprepared canals. The other groups were instrumented with rotary ProTaper Universal files up to size F3. Group (B) was irrigated with 1% NaOCl at room temperature, Group (C) with 1% NaOCl heated to 70 °C, Group (D) with 5.25% NaOCl at room temperature, and Group (E) with 5.25% NaOCl heated to 70 °C. Saline was used in Group (F). The roots were sectioned into 2-mm-thick disks that underwent compression testing using a universal testing machine. Data were analyzed using one-way ANOVA and post hoc Tukey tests. The significance level was set at p ≤ 0.05. Results A total of 255 disks were tested. The control group showed the highest compressive strength (p = 0.0112). However, this did not differ significantly from that of heated (p = 0.259) or unheated (p = 0.548) 1% NaOCl. There were no statistically significant differences between the groups of instrumented teeth. Conclusion Within the conditions of this study, irrigation with NaOCl at different concentrations and temperatures during root canal preparation did not affect the compressive strength of root dentin. Clinical Relevance: This study demonstrates that the use of NaOCl as a root canal irrigant is not associated with a clinically relevant decrease in root compressive strength, especially when compared to saline

Undergraduate Endodontic Training and Its Relation to Contemporary Practice: Multicenter Cross-Sectional Study in Saudi Arabia

Background and Objectives. The aim of this study is to explore the current state of endodontic practical training in Saudi dental schools and its relevance to contemporary endodontic practice. Materials and Methods. An online questionnaire was developed and emailed to all dental schools in Saudi Arabia. This questionnaire was answered by the endodontic undergraduate program director. The data collected were analysed using descriptive statistics. Results. The response rate was 96.15%, which means twenty-five out of twenty-six dental schools participated in the study. The majority of the academic supervisors was endodontists (92%). The use of magnification and ultrasonic tips was not required by 84% and 76% of the dental schools, respectively. The main endodontic treatment techniques were the step-back technique and gates glidden for cleaning and shaping (76%) and cold lateral compaction for obturation (92%). Conclusions. The dental students were supervised by endodontic specialists and trained to use traditional endodontic methods. Encouraging dental educators to train students to use modern technology and equipment would probably improve their graduate clinical skills and performance

Prevalence of bone loss surrounding dental implants as detected in cone beam computed tomography: a cross-sectional study

Objectives The objective of this study was to assess the prevalence of crestal, and apical bone loss (CBL & ABL) associated with dental implants in CBCT scans. The second objective was to assess the radiographic stage of implant disease and the visible predisposing factors. Materials and Methods The CBCT scans that were taken from January 2015 to January 2022 in King Saud Medical City were screened to examine the marginal and periapical condition of dental implants. Information related to demographic variables, stage of bone loss, and radiographically evident predisposing factors were collected. The results were analyzed using descriptive statistics, chi-square test, and logistic regression analysis. Results In total, 772 implant scans were analyzed. The prevalence of crestal bone loss and apical bone loss around the implants were 6.9% and 0.4% respectively. The amount of bone loss was moderate in 52.8% of cases of CBL and 100% mild in cases of ABL. The risk factors for CBL were patient age (p < 0.001), implant location (p < 0.001), bone loss in proximal teeth (p < 0.001), and adjacent edentulous sites (p < 0.001). The risk factors for ABL were adjacent periapical infection (p < 0.001) and endodontic therapy (p = 0.024). Conclusion The prevalence of CBL and ABL was low. The CBCT can be used as a diagnostic tool for studying the prevalence of bone loss associated with peri-implant disease and relevant risk factors. The implantation of CBCT to evaluate the success and the prognosis of dental implants or the treatment of peri-implant diseases can be further considered in future research

Additional file 1 of Effect of sodium hypochlorite temperature and concentration on the fracture resistance of root dentin

Supplementary Material 1. S1 file contains the whole dataset