Apical extrusion of debris following the use of single-file rotary/reciprocating systems, combined with syringe or ultrasonically-facilitated canal irrigation.

AIM: The aim of the study is to quantify the amount of debris extrusion after instrumentation with single-file rotary and reciprocating systems used either with conventional irrigation (CI) or passive ultrasonic irrigation (PUI) systems. METHODOLOGY: Sixty extracted human mandibular incisors were randomly assigned to two groups (n = 30); rotary single-file system, One Shape (OS-Group 1) and reciprocating single-file system, WaveOne (WO-Group 2) instruments. The two groups were further subdivided into two subgroups (n = 15); (A) PUI and (B) CI. The apically extruded debris was collected in preweighed glass vials as per the Myers and Montgomery method. After drying, the mean weight of debris was assessed with a microbalance and statistically analyzed using analysis of variance and Student's t-test. RESULTS: The reciprocating file system produced significantly more debris compared to the rotary file system using either of the irrigation systems (P = 0.04). CI produced significantly more (P = 0.02) debris extrusion compared to PUI irrespective of the file system used. CONCLUSION: Under the conditions of this study, both systems caused apical debris extrusion. Rotary single-file system produced less debris extrusion compared to reciprocating single-file system. Use of PUI may be advocated as an alternative to CI, as it causes lesser apical debris extrusion.

Influence of root canal curvature on the accuracy of an electronic apex locator: An in vitro study.

OBJECTIVE: This study investigated whether the canal curvature has an influence on the accuracy of Electronic Apex Locator. MATERIALS AND METHODS: Sixty mandibular posterior teeth were decoronated. A number (No.) 10 file was inserted into the mesiobuccal canal and radiographs were taken to determine the degree of curvature by Schneider's method. Samples were divided into three groups of mild (<20°), moderate (20-36°) and severe curvature (>36°). After enlarging the orifice, the actual canal length was determined by introducing a file until the tip emerged through the major foramen when observed under 20X magnification. The teeth were embedded in an alginate model and the Root ZX was used to determine the electronic length. The data was analyzed by Kruskal-Wallis test followed by Mann-Whitney test. RESULTS: The difference in measurement of Actual and Electronic working length was statistically significant between group 1 and 2 (P < 0.05) as well as between group 1 and group 3 (P < 0.05) with group 1 showing the lowest difference. CONCLUSION: Considering ± 0.5 mm as tolerance limit for accuracy, the device was 95% accurate for the mild curvature group and 80% accurate for moderate and severe groups.

The prevalence of bilateral three-rooted mandibular first molar in Indian population.

INTRODUCTION: The purpose of the present study was to evaluate the prevalence of bilateral three-rooted mandibular first and second molars in Indian population. MATERIALS AND METHODS: A total of 215 patients were screened bilaterally for mandibular first and second molar and 430 samples of periapical radiographs were obtained. The gender, symmetry, and prevalence of three-rooted mandibular first and second molars were recorded. The correlation between left and right side occurrences and distribution were recorded and analysed using Z-test. RESULTS: The results showed that 33 teeth had three-rooted mandibular first molars, 16 male and 17 female (P=0.442). Overall, 21 teeth of right jaw and 12 teeth of left jaw (P=0.103) showed presence of an extra-root. The prevalence of three-rooted mandibular first molars was 7.67% and second molar was 0.23%. The bilateral frequency distribution was 3.72% for the first molar. There was no statistically significant difference between right side and left side mandibular molars. Also, gender did not show a significant relationship with this variant. CONCLUSION: The endodontic treatments of first mandibular molars require a careful clinical approach in Indian population as a high racial prevalence of 7.67% three-rooted molars was found. However, in the same population, 0.23% mandibular second molars had three roots.

Microleakage evaluation of Silorane-based composite and methacrylate-based composite in class II box preparations using two different layering techniques: an in vitro study.

AIM: The aim of this study was to compare the microleakage in Class II box preparations with the gingival margin above and below the cemento-enamel junction (CEJ) restored with Silorane composite and methacrylate composite using two different layering techniques. MATERIALS AND METHODS: Standardized box preparations (mesial box 1 mm above the CEJ and distal box 1 mm below the CEJ) were prepared in 60 upper premolars. The teeth were randomly divided into four groups containing 15 samples each; Group I: Restored with a Silorane composite using an oblique layering technique, Group II: Restored with Silorane composite using a vertical layering technique, Group III: Restored with methacrylate composite using the oblique layering technique, and Group IV: Restored with methacrylate composite using the vertical layering technique. The samples were stored in distilled water, followed by thermocycling and immersed in 2% methylene blue. The samples were sectioned and evaluated for microleakage at the gingival margin. STATISTICAL ANALYSIS: Kruskal-Wallis, Fischer exact test, Wilicoxon test, and Mann-Whitney U test. RESULTS: Silorane composite had significantly lesser microleakage. No significant difference in microleakage was observed above and below the CEJ for Silorane-based composite. CONCLUSION: Silorane composite resin showed lesser microleakage compared to methacrylate composite resin. CLINICAL SIGNIFICANCE: The Silorane-based composites improve the marginal adaptation due to their reduced shrinkage, thereby decreasing the residual stress at the adhesive-tooth interface.