Comparative evaluation of the sealing ability of different obturation systems used over apically separated rotary nickel-titanium files: An in vitro study

Gap volume and sealer penetration of C-shaped root canals obturated with cold hydraulic technique and calcium silicate sealer

This study compared the gap volume and sealer penetration in C-shaped root canals prepared with adaptive core rotary files and obturated with cold hydraulic compaction using calcium-silicate sealer, warm vertical hybrid compaction, or lateral compaction using epoxy-resin sealer. Thirty-six extracted mandibular molars with pulpal floor configuration Types I and III were used. The teeth were prepared using XP-Shaper and XP-Finisher and obturated with: group 1: cold hydraulic compaction/calcium silicate, group 2: warm vertical hybrid compaction/epoxy resin, or group 3: lateral compaction/epoxy resin. The gap volume was evaluated using μ-CT. The sealer penetration depth and area were evaluated using confocal laser scanning microscopy. The gap volume in groups 1, 2, and 3 was 0.82%, 0.24%, 0.80%, respectively, which were not significantly different (p > 0.05). The gap volumes in the obturated C-shaped canals were not significantly different among the CHC/CSBS, WHC/ERS, or LC/ERS groups. CHC/CSBS was the most convenient technique.

Microleakage of five separated nickel-titanium rotary file systems in the apical portion of the root canal

Background

The aim of this study was to evaluate the rate of apical microleakage following the fracture of five types of nickel-titanium rotary file systems (ProTaper Universal, Mtwo, RaCe, Revo-s, HeroShaper) in the apical one-third of the canal.

Materials and Methods

In this laboratory experiment, 49 mandibular premolars were collected and randomly divided into seven groups. Root canal treatment was performed by five different rotary file systems with different cross-sections. All files, except in the control groups, were scratched at the 3-mm end by a handpiece. After separation of the apical end of the file in the root canal, the apical seal was measured, using the fluid infiltration technique. Data were analyzed in SPSS, using one-way ANOVA and Tamhane's T2 tests at P < 0.05.

Results

The Hero Shaper and RaCe files showed the highest (3.14 μL/min) and the lowest (2.51 µL/min) rates of microleakage over time, respectively. There were significant differences between the Hero Shaper and RaCe files and between Hero Shaper and ProTaper files in terms of microleakage (Tamhane's T2 tests, P < 0.05).

Conclusion

The presence of a separated file and its cross-section type affects the apical microleakage.

Filling quality of several obturation techniques in the presence of apically separated instruments: A Micro-CT study

Separated root canal instruments may affect the quality of root canal obturation and hence the survival of endodontically treated teeth. Obturation techniques may influence filling-quality. The aim was to evaluate the obturation quality of teeth filled with different obturation techniques in the presence of apically separated instruments using micro-computed tomography (μ-CT). Notched ProTaper F2 rotary-files were separated in the apical third of 36-human mandibular incisors with single root/canal and mature apex. Samples were filled by an endodontist according to one of the following obturation techniques (n = 12): cold lateral-compaction (CLC), single-cone (SC) and thermoplastic injection (TI). Samples were scanned by the Skyscan 1,274® μ-CT device after 1-week at 37°C in 100% humidity. Images of the sections were evaluated with CTan software in terms of total-volume and volume percentage of the filling materials and voids between coronal end of the separated instrument and gutta-percha/sealer filled void-free sections. Data was analyzed using Kruskal-Wallis and Mann Whitney-U tests with a significance level of 5%. Kruskal-Wallis revealed differences among groups (p < 0.05).Pairwise comparisons revealed that less volume of voids were measured in SC (0.02 ± 0.03 mm³ ) compared to CLC (0.15 ± 0.16 mm³ ) and TI (0.18 ± 0.24 mm³ ) (p < 0.05); while TI was statistically similar with CLC (p > 0.05). Percentages of volumes of voids and filling materials were as follows for SC, CLC and TI, respectively: 8.88 ± 18.52% and 24.45 ± 38.40%, 46.92 ± 33.53% and 53.07 ± 33.53%, 40.54 ± 33.85% and 42.79 ± 34.45%. The obturation technique may have a significant impact on the volume of voids in the presence of a separated file. No obturation technique produced a void-free root canal filling.

In Vitro Comparative Evaluation of Cleaning Efficacy and Volumetric Filling in Primary Molars: Cone Beam Computed Tomography Evaluation

Introduction:

Pulpectomy of primary teeth is mostly carried out with hand files and broaches which is tricky and time consuming procedure. The development of new design features like varying tapers, non-cutting safety tips and varying length of cutting blades have resulted in new generation of rotary instruments.

Aim:

To compare and evaluate cleaning efficacy, canal preparation and volumetric filling using conventional files and rotary V Taper files through cone beam computed tomography.

Materials and Method:

Thirty extracted primary molars were selected. The teeth were randomly divided into three groups each containing 10 teeth i.e. 30 canals in each group. Group A was instrumented with K files; Group B rotary V Taper files and Group C was Hybrid group. Sodium hypochlorite (1%) was used for irrigation. Root canal filling was done with Zinc Oxide Eugenol cement in all groups. The volumetric analysis i.e. Percentage of Volume (POV) of the root canal filling in primary molars was done through CBCT Software.

Result:

In present study, p- value was found to be significant (<0.05). Almost 100% of canals of hybrid group were fully filled and 63.3% of canals of hand filing group were partially filled. The filling was found to be dense and no. of voids was least in hybrid group.

Conclusion:

Clinical time required in primary molar endodontics, especially with unpredictability and difficulty of canal morphology, is inevitable. The study confirms superior ability of rotary-file systems to shape severely curved canals with less time and significant decrease in procedural errors like partial filling, voids and inappropriate canal preparation.