Comparative Evaluation of Root Reinforcement Using MTA-based, Epoxy Resin-based, and Silicone-based Endodontic Sealers in Canals Instrumented with Single-file Rotary System: An In Vitro Study.

AIM: To evaluate root reinforcement by four different sealers, namely, AH Plus, MTA Fillapex, Dia-ProSeal, and GuttaFlow 2, on endodontically treated teeth. MATERIALS AND METHODS: Sixty human mandibular premolars were randomly divided into four groups of 15 teeth each, according to the type of sealer used: Group I AH Plus, Group II MTA Fillapex, Group III Dia-ProSeal, and Group IV GuttaFlow 2. All samples were decoronated to a length of 13 mm from the apex. Root canals were prepared by OneShape, 25/0.06 taper file and obturated with a matching single cone gutta percha (25/0.06) using the above-mentioned sealers. All samples were subjected to load by universal testing machine until a point at which root fractured, which was recorded. RESULTS: Teeth obturated with GuttaFlow 2 showed the maximum fracture resistance followed by AH Plus, Dia-ProSeal, and MTA Fillapex. There was no significant difference in fracture resistance between AH Plus and Dia-ProSeal. CONCLUSION: Teeth obturated with GuttaFlow 2 sealer, which has powdered gutta percha particles, showed the highest fracture resistance. CLINICAL SIGNIFICANCE: According to the results obtained from this study, obturation of roots with GuttaFlow 2 increased the resistance of root canal-filled teeth to vertical root fracture.

A comparative evaluation of the effect of 8% and 17% ethylenediaminetetraacetic acid exposure for 1 min and 10 min on the fracture resistance of endodontically treated roots: An in vitro study.

OBJECTIVE: The objective of this study was to evaluate the effect of 8% and 17% ethylenediaminetetraacetic acid (EDTA) exposure for 1 min and 10 min on the fracture resistance of endodontically treated roots. METHODOLOGY: Sixty human single-rooted teeth were decoronated and divided into six groups (n = 10). Canal preparation was carried out except in negative control group, using the ProTaper rotary file system. Final irrigation was performed using distilled water, 17% EDTA for 1 min and 10 min, 8% EDTA for 1 min and 10 min. Thereafter, roots were obturated with ProTaper F3 Gutta-percha points and AH Plus sealer using a single-cone technique. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with one-way analysis of variance and post hoc Tukey test. RESULTS: Analysis of results showed that the unprepared roots showed the highest fracture resistance and roots irrigated with 17% EDTA for 10 min showed the lowest fracture resistance. The mean fracture resistance of unprepared roots, roots irrigated with 8% EDTA for 10 min and 17% EDTA for 1 min was significantly higher than roots irrigated with 8% EDTA for 1 min, 17% EDTA for 10 min and distilled water. CONCLUSION: From a clinical viewpoint, if EDTA has to be used, it is safer to use higher concentration for a shorter application time or a low concentration with a longer application time. Prolonged use of high concentrations of EDTA might increase the risk of root fracture.

Evaluation of smear layer removal from ultrasonically prepared retrocavities by three agents.

OBJECTIVES: To evaluate the efficacy of 35% orthophosphoric acid, 24% ethylenediaminetetraacetic acid (EDTA) and 10% citric acid in the removal of smear layer from retrocavities prepared with ultrasonic retro-tips using scanning electron microscopy. MATERIALS AND METHODS: Root canals of fifty single-rooted teeth were cleaned, shaped, and obturated with gutta-percha and AH plus sealer. The apical 3 mm of each root was sectioned with a diamond disc and retrograde cavities were prepared with Kis # 1 ultrasonic retro-tips to a depth of 3 mm. Retro cavities in Group I were treated with a gel of 35% orthophosphoric acid for 15 seconds, Group II were treated with a gel of 24% EDTA at neutral pH for 2 minutes, and Group III were treated with a gel of 10% citric acid for 2 minutes, followed by 1 minute rinsing with distilled water for all groups. The samples were prepared for scanning electron microscopic observation. Scoring was performed for the presence of the smear layer on the walls of the retrocavity. RESULTS: In the orthophosphoric acid group, it was observed that all dentinal tubules were open in 70% of the samples. The majority of analyzed samples in EDTA and citric acid group showed dentinal tubules covered with the smear layer. CONCLUSIONS: Application of 35% orthophosphoric acid gel for 15 seconds on retrocavities prepared with ultrasonic retro-tips is the most effective means for removal of smear layer.

An in vitro evaluation of effect of eugenol exposure time on the shear bond strength of two-step and one-step self-etching adhesives to dentin.

OBJECTIVES: To evaluate the effect of the eugenol exposure time of an eugenol-based provisional restorative material on the shear bond strength of two-step and one-step self-etching adhesives to dentin, at three different time intervals of 24 h, 7 days, and 14 days. MATERIALS AND METHODS: Forty extracted human posterior teeth were sectioned mesiodistally to obtain two halves and the resulting 80 halves were randomly assigned into four groups of 20 specimens each (Group-I, -II, -III, and -IV). Cavities of specified dimensions were prepared to expose dentin surface. In Group-I, temporarization was carried out with noneugenol cement (Orafil-G) for 24 h (control group). In Group-II, -III, and -IV, temporarization was carried out with eugenol cement (intermediate restorative material (IRM)) for 24 h, 7 days, and 14 days, respectively. Each group was further divided into two subgroups of 10 teeth each for two-step (Adper SE Plus) and one-step (Adper Easy One) self-etch adhesive systems, respectively. A plastic tube loaded with microhybrid composite resin (Filtek Z-350, 3M) was placed over the dentin surface and light cured. The specimens were subjected to shear stress in universal testing machine. RESULTS: Group-II yielded low shear bond strength values compared with Group-III, -IV, and Group-I, which was statistically significant. CONCLUSIONS: The prior use of eugenol containing temporary restorative material reduced the bond strength of self-etch adhesive systems at 24-h period. No reduction in bond strength at 7 or 14 days exposure was observed with either two-step or one-step self-etch adhesive.