In vitro study on the impact of various polishing systems and coffee staining on the color stability of bleach-shaded resin composite.

OBJECTIVE: To evaluate the effects of different polishing techniques and coffee staining on the color stability of four commercially available bleach-shade composite resins, namely microhybrid, nanohybrid, nanofilled, and injectable nanohybrids. MATERIAL AND METHODS: A total of 224 discs (8 mm diameter and 2 mm thickness) were fabricated from four different bleach-shade composite resins, namely microhybrid (Gradia Direct Anterior), nanohybrid (Palfique LX5), nanofilled (Filtek Universal), and injectable nanohybrid (flowable G-aenial universal injectable). The composite resin groups were polished via four techniques: no polishing, 4-step polishing using aluminum oxide discs, 3-step polishing using silicon rubber diamond discs, and one-step polishing. Half of each group was immersed in water, while the other half was immersed in coffee for 12 days (n = 7). Colors were measured using a clinical spectrophotometer, and color differences were calculated (ΔE). The results were analyzed statistically. RESULTS: The alterations in color were significantly influenced by the techniques employed for finishing and polishing techniques, composite resin type, and degree of coffee staining. Regardless of the polishing technique and storage medium, different material types showed a significant color change (ΔE) at P < 0.001. Filtek exhibited the most significant color change, followed by Gradia and Palfique, with no significant differences between them. In addition, Different polishing techniques resulted in significant color changes (P < 0.001). The highest degree of color change was seen in the no-polishing group, followed by the 4-step and 1-step polishing groups, with negligible differences between each other. Also, Storage media had a significant effect on ΔE values. CONCLUSION: Appropriate finishing and polishing procedures can improve the color stability of bleach-shaded composite resins. Coffee has a deleterious effect on color; however, injectable flowable nanohybrid composites are more resistant to staining.

Correction: Microcomputed tomography analysis of curved root canal preparation when coronal flaring and glide path files used with heat-treated nickel titanium rotary files.

[This corrects the article DOI: 10.1371/journal.pone.0299896.].

Microcomputed tomography analysis of curved root canal preparation when coronal flaring and glide path files used with heat-treated nickel titanium rotary files.

The objective was to evaluate the effect of glide path and coronal flaring on the dentin volume removal and percentage of touched walls in curved canals using two heat-treated rotary files. The mesiobuccal canal of forty-eight, randomly selected, extracted mandibular molars was divided into two groups of 24 each, according to the type of instrument used (RACE EVO and EdgeSequel rotary files). Each group was further divided into three subgroups; Group (A): Control using one file shaped to 04/30, Group (B) with a glide path (EdgeGlidePath (EGP)), and Group (C): with a glide path and coronal flaring (EGP and EdgeTaper Platinum (ETP) SX file respectively). The root canals were then instrumented using the assigned instruments. The assessment was carried out using micro-CT. The comparison of the mean values of the tested groups about dentin volume removal and percentage of untouched walls did not reach statistical significance (p<0.05). Glide path and coronal flaring had an insignificant effect on the dentin volume removal and percentage of untouched walls in curved canals.

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

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.

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.

Application of advanced platelet-rich fibrin for through-and-through bony defect during endodontic surgery: Three case reports and review of the literature.

BACKGROUND: The use of advanced platelet-rich fibrin (A-PRF) membranes for guided bone and tissue regeneration in through-and-through defects after endodontic surgery was explored in three cases. CASE SUMMARY: Herein, three patients presented to the endodontic clinic suffering from apical periodontitis, associated with large bone resorption and related to previously endodontically treated teeth. Periapical surgery was indicated in these cases and the osteotomy site was covered by A-PRF membrane. Cone-beam computed tomography (CBCT) was used to assess the cases before and after the surgery. CONCLUSION: Four months post-surgery, the recall CBCT scan showed complete obliteration of the osteotomy with newly formed bone. A-PRF membrane showed promising results and was an advantageous addition to surgical endodontic treatment.

Assessment of the effect of spacer material on gap and void formation in an endodontic temporary restoration using micro-computed tomography.

This study aimed to evaluate the effect of two spacer materials (cotton pellet and polytetrafluoroethylene [PTFE]) on gap and void formation in the Cavit restoration used for endodontic temporization. Thirty-four extracted human single-rooted premolars were matched and allocated into two groups (n = 17/group) according to the access cavity spacer (cotton pellet or PTFE). Standardized endodontic access cavities were prepared in all the teeth. Subsequently, the teeth were scanned by micro-computed tomography (micro-CT) to determine the volume of the access cavities. The teeth were then temporized by placing either cotton pellet or PTFE as spacer materials on the canal orifices, followed by the Cavit restoration. Following the temporization procedure, the teeth were subjected to a second micro-CT scan to determine the percentage volume of gaps and voids along the margins and within the Cavit restoration, respectively. Statistical analysis was performed using the Shapiro-Wilk and Wilcoxon signed-rank tests with a 5% significance level. The PTFE spacer was associated with significantly less gap formation between the Cavit restoration and the access cavity walls (P < 0.05) compared with the cotton pellet. No difference existed in void formation between the groups (P > 0.05). These findings indicate that the spacer material placed under the Cavit restoration can influence the quality of overlying restoration. PTFE was associated with less gap formation and, therefore, performed better than the cotton pellet as a spacer material beneath the Cavit restoration during endodontic treatment.

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

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.

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.

Efficiency of diode laser and ultrasonic-activated irrigation in retreatment of gutta percha and bioceramic sealer: An in vitro study.

This study was to determine the effectiveness of diode laser (LI) and ultrasonic (UI)-activated irrigation with or without a surfactant as adjunct techniques during the retreatment of gutta-percha and tricalcium silicate-based sealer (BC) sealer. Forty-two single-rooted premolars were instrumented and filled with gutta-percha and BC sealer, then retreated using NiTi retreatment rotary files. Teeth were randomly divided into three equal groups: Control (manual irrigation), UI and LI groups. Each group was subdivided into 2.5% NaOCl irrigant and ChlorCid™ï¸ Surf subgroups. The amount of material removed following UI and LI was significantly greater than that of manual irrigation (p < 0.0001). However, there was no significant difference between the surfactant subgroups, irrespective of irrigation technique (p = 1.00, p = 0.535, p = 0.805). The use of UI and LI adjuncts to NiTi rotary retreatment techniques showed significant improvement in gutta-percha with BC sealer removal. However, surfactants had no effect on the efficacy.

The objectives and instructional design of undergraduate endodontic program: multicenter cross-sectional study in Saudi Arabia.

BACKGROUND: Identify the objectives and the instructional design of undergraduate endodontics in dental schools in Saudi Arabia. METHODS: The online questionnaire was developed from an original survey conducted in the United Kingdom. The questionnaire was modified for purpose of the study and the region of interest. Then it was directed and emailed to the undergraduate endodontic program directors in twenty-six dental schools in Saudi Arabia. The results were analyzed using descriptive statistics and the Chi-square and Fisher's exact tests. RESULTS: The response rate was 96.15%. The number of credit hours for preclinical endodontic courses was up to four credit hours (84%). Students were clinically trained to do vital pulp therapies (92%), root canal treatment (100%), and root canal retreatment (68%). The majority of dental schools define the minimum clinical requirements (92%). Practical and clinical competency exams were used to evaluate students' performance (92% and 84% respectively). The students were trained to treat cases of minimal (52%) to moderate complexity (48%). Endodontic treatment consent and difficulty assessment form were used by 32% and 60% of dental schools respectively. There was no significant difference in the instructional design between public and private dental schools (P > 0.05). CONCLUSION: The endodontic undergraduate objectives were to graduate competent clinicians who acquired basic science of endodontics and who know their limitations as it is necessary for a safe general dental practice. The use of endodontic treatment consent and case difficulty assessment should be wisely considered in clinical training.

Common Temporization Techniques Practiced in Saudi Arabia and Stability of Temporary Restoration.

INTRODUCTION: Coronal leakage is detrimental to the long-term success of root canal treatment (RCT). While much emphasis is being placed on the quality of the final restoration, little attention is given to the temporary restoration placed in between root canal treatment appointments. The aim of this study was to survey temporization techniques practiced in Saudi Arabia and the frequency of observing temporary material breakdown or complete loss. MATERIALS AND METHODS: An online questionnaire was distributed among general dentists, dental specialists, and clinical trainees in undergraduate and postgraduate dental programs. The sample size was estimated at 370 participants. Data were analyzed using descriptive statistics and chi-square tests. RESULTS: The total number of participants who met the inclusion criteria was 525. The majority of them (94.6%) were practicing two-visit RCT. The most common temporization materials were Cavit (50.3%) followed by glass ionomer cement (32%). The majority (72.6%) of participants claimed they allow a thickness of 2-3 mm for temporary restorations. Many participants (60.4%) used a spacer material during temporization, and the cotton pellet was the most common spacer material. Temporary restoration breakdown or complete loss was a common observation. Although the duration between the two RCT visits was 2 weeks or less for 83.6% of participants, only 19.6% of participants claimed that they rarely observed temporization breakdown. CONCLUSION: Two-visit RCT is commonly practiced in Saudi Arabia, and endodontists performed significantly more single-visit procedures. Temporization practices may lack uniformity; however, clinicians were more likely to use calcium sulfate-derived material for two weeks or less. They allow for 2-3 mm thickness restoration and use a cotton pellet as a spacer. According to their clinical observation, temporary material breakdown or complete loss was frequent. This mandates further attention in research and education.