Comparative evaluation of shaping ability of V-Taper 2H, ProTaper Next, and HyFlex CM in curved canals using cone-beam computed tomography: An in vitro Study.

AIM: The aim of this study was to compare the canal transportation and canal centering ability in the preparation of curved root canals after instrumentation with V-Taper 2H, ProTaper Next (PN), and Hyflex CM files using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20 to 40 were divided according to the instrument used in canal preparation into three groups of ten samples each: V-Taper 2H (Group 1), PN (Group 2), and Hyflex CM (Group 3). The teeth were instrumented according to manufacturer's guidelines up to 30 no. apical preparation. Canals were scanned using a CBCT scanner before and after preparation to evaluate the transportation and centering ratio at 3 mm, 6 mm, and 9 mm from the apex. The amount of transportation and centering ability was assessed. The three groups were statistically compared with analysis of variance and post hoc Tukey test. RESULTS: All instruments maintained the original canal curvature with significant differences between the different files. Data suggested that V-Taper 2H files presented the best outcomes for both the variables evaluated. V-Taper 2H files caused lesser transportation and remained better centered in the canal than PN and Hyflex CM files. However, it was seen that PN caused less transportation in apical level than Hyflex CM. CONCLUSION: The canal preparation with V-Taper 2H showed lesser transportation and better centering ability than PN and Hyflex CM.

Evaluation of softening ability of Xylene & Endosolv-R on three different epoxy resin based sealers within 1 to 2 minutes - an in vitro study.

OBJECTIVES: This study evaluated the efficacy of Endosolv-R and Xylene in softening epoxy resin based sealer after 1 to 2 min exposure. MATERIALS AND METHODS: Sixty Teflon molds (6 mm × 1.5 mm in inner diameter and depth) were equally divided into 3 groups of 20 each. AH 26 (Dentsply/De Trey), AH Plus (Dentsply/De Trey), Adseal (Meta-Biomed) were manipulated and placed in the molds allotted to each group and allowed to set at 37℃ in 100% humidity for 2 wk. Each group was further divided into 2 subgroups according to the solvents used, i.e. Xylene (Lobachemie) and Endosolv-R (Septodont). Specimens in each subgroup were exposed to respective solvents for 1 and 2 min and the corresponding Vicker's microhardness (HV) was assessed. Data was analysed by Mauchly's test and two-way analysis of variance (ANOVA) with repeated measures, and one-way ANOVA. RESULTS: Initial hardness was significantly different among the three sealers with AH Plus having the greatest and Adseal having the least. After 2 min, Xylene softened AH Plus and Adseal sealer to 11% and 25% of their initial microhardness, respectively (p < 0.001), whereas AH 26 was least affected, maintaining 89.4% of its initial microhardness. After 2 min, Endosolv-R softened AH 26, AH Plus and Adseal to 12.7, 5.6 and 8.1% of their initial microhardness, respectively (p < 0.001). CONCLUSIONS: Endosolv-R was a significantly more effective short term softener for all the tested sealers after 2 min whereas Xylene was an effective short term softener against AH plus and Adseal but less effective against AH 26.

A comparative evaluation of cytotoxicity of root canal sealers: an in vitro study.

OBJECTIVES: The objective of this in vitro study was to evaluate and compare the cytotoxicity of four different root canal sealers i.e. Apexit Plus (Ivoclar Vivadent), Endomethasone N (Septodont), AH-26 (Dentsply) and Pulpdent Root Canal Sealer (Pulpdent), on a mouse fibroblast cell line (L929). MATERIALS AND METHODS: Thirty two discs for each sealer (5 mm in diameter and 2 mm in height) were fabricated in Teflon mould. The sealer extraction was made in cell culture medium (Dulbecco's Modified Eagle's Medium, DMEM) using the ratio 1.25 cm(2)/mL between the surface of the sealer samples and the volume of medium in a shaker incubator. Extraction of each sealer was obtained at 24 hr, 7th day, 14th day, and one month of interval. These extracts were incubated with L929 cell line and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay was done. Two-way ANOVA for interaction effects between sealer and time and Post-hoc multiple comparison using Tukey's test across all the 16 different groups were used for statistical analysis. RESULTS: Apexit Plus root canal sealer was significantly less toxic than other sealers (p < 0.05) and showed higher cellular growth than control. Endomethasone N showed mild cytotoxicity. AH-26 showed severe toxicity which became mild after one month while Pulpdent Root Canal Sealer showed severe to moderate toxicity. CONCLUSIONS: Apexit Plus was relatively biocompatible sealer as compared to other three sealers which were cytotoxic at their initial stages, however, they became biocompatible with time.