In vitro comparison of cyclic fatigue resistance of TruNatomy in single and double curvature canals compared with different nickel-titanium rotary instruments.

BACKGROUND: The purpose of this study was to compare the cyclic fatigue resistance of newly developed TruNatomy instruments (TRN) in single and double (S-shaped) curvature canals with HyFlex CM (HCM), Vortex Blue (VB) and RaCe (RC) instruments. METHODS: Size 20/.04 taper and size 25/0.04 of HCM, VB and RC were used. For TRN instruments, size 20/.04 taper (small) and size 26/.04 taper (prime) were used. The instruments were tested in artificial canals with double curvature (coronal curve; 60° curvature, 5 mm radius and apical curve; 70° curvature and 2 mm radius) and single curvature (60° curvature, 5 mm radius). The number of cycles to failure (NCF) was recorded. Data were statistically analyzed by Kruskal-Wallis and Dunn's multiple comparison tests. Weibull analysis was performed on NCF data. Statistical significant was set at p < 0.05. RESULTS: TRN and HCM revealed higher NCF compared with the other instruments for both tested sizes in single and double curvature canals (p < 0.05). TRN and HCM showed no statistically significant difference in the NCF (p > 0.05). The probability of survival was higher for HCM and TRN instruments than VB and RC instruments. CONCLUSIONS: HCM and TRN instruments were more resistant to cyclic fatigue than VB and RC instruments in single and double curvature canals. HCM and TRN instruments were anticipated to survive with higher number of cycles than the other tested instruments. RC instrument had the lowest fatigue resistance than the other instruments.

Internal Bleaching of Endodontically Treated Teeth: A Dental Practitioner's Perspective from Kingdom of Saudi Arabia.

AIM: To determine the knowledge and attitude of dental practitioners (DPs) for internal bleaching technique (IBT) in Kingdom of Saudi Arabia. MATERIALS AND METHODS: A cross-sectional study was developed based on a convenient sampling of dental practitioners and specialists working in Kingdom of Saudi Arabia. DPs responded to a structured, self-administered questionnaire for evaluation of their knowledge and attitude toward IBT. The questionnaire had two components: (i) the characteristics of the study participants; and (ii) the items related to the internal bleaching technique (IBT). Data analysis was conducted using SPSS (version 25.0), with descriptive statistics and a bivariate analysis. RESULTS: A total of 532 dental practitioners (61.3% males and 38.7% females) participated in this study. The response rate of participation was estimated at 92.5%. Almost 37% participants considered the sodium perborate as the most commonly used dental material for internal bleaching. Almost 70% participants reported that superficial enamel discoloration was a contraindication for internal bleaching in endodontically treated teeth. CONCLUSION: DPs have good knowledge and attitude on use of IBT for discolored teeth. In general, there is a need to improve knowledge and attitude of dental professionals about the IBT by attending continuing dental educational programs. CLINICAL SIGNIFICANCE: Saving of the remaining tooth structure is a main principle of the different types of dental treatments. So the IBT should be known for all dental practitioners to use it before going to more aggressive dental treatment options such as full crowns. How to cite this article: Doumani M, Alotaibi AN, Al Hussain F, et al. Internal Bleaching of Endodontically Treated Teeth: A Dental Practitioner's Perspective from Kingdom of Saudi Arabia. J Contemp Dent Pract 2019;20(10):1141-1145.

Preference and usage of intracanal medications during endodontic treatment.

OBJECTIVES: To investigate the preferences of general dental practitioners (GDPs) and endodontists in using endodontic intra-canal medications (ICMs). METHODS: This observational and descriptive study was conducted in 2014 in the western province of Saudi Arabia. Following ethical clearance and 2 pilot studies, a web-based questionnaire was electronically sent to 375 randomly and systematically selected GDPs and all endodontists in the western province (n=49). An accompanying e-mail explained the study's aims and confirmed that the data yielded would remain confidential. The responses were collected, and the data was analyzed using the Chi-square test at p=0.05. RESULTS: Significantly, the highest proportion of respondents (53.7%) reported disinfection of the root canals as the main function of ICMs. Calcium hydroxide (CH) was the preferred material of the majority of those who used the same ICM in all cases (85.7%). While the vast majority of all endodontists (87.5%) used CH after pulp extirpation, 48.5% of GDPs used formocresol (p less than 0.001). Almost 30% of those who used ICMs after pulp extirpation did not do so after cleaning and shaping of vital cases. Most endodontists used CH (62.5%) and antibiotics (37.5%) in necrotic pulp cases without apical lesions, which were significantly greater than those of GDPs who did the same (43.8% and 17.2%). CONCLUSIONS: Participants were aware that the main function of ICMs is disinfection of the root canal system. However, it is clear that GDPs should reduce their reliance on phenol- and formaldehyde-based medications. There was a distinct trend toward the use of ICMs, especially CH, in necrotic pulp cases.

A finite element study on the mechanical behavior of reciprocating endodontic files

To evaluate the mechanical behavior of reciprocating endodontic files, comparing nickel-titanium NiTi and stainless steel 316L St.St. 316L as manufacturing material for such instruments. METHODS: A three-dimensional finite element model was designed for this study. The simplified instrument model geometry was created on commercial CAD/CAM software. Real strain stress curves of St.St. 316L and NiTi were used in the analysis. Non-linear static analysis was performed to simulate the instrument inside root canal at an angle of 45° in the apical portion, and subjected to torsion of 0.3 N.cm. RESULTS: Non-linear NiTi material showed super elasticity and high functionality in such applications. Very high levels of stress appeared in the file at 3 mm from the tip close to yield point. CONCLUSIONS: St. St. 316L is not suitable for manufacturing reciprocating instruments. Modeling of the instrument with equivalent circular cross-sectional area did not affect results quality. Reciprocating instruments have short lifespan, thus manufacturers recommend using one file per tooth. Reciprocating instruments are recommended for less experienced dentist...