RESUMO
BACKGROUND: Teeth with apical periodontitis that either persisted or developed after initial root canal treatment is most often indicated for retreatment procedure. The present study was conducted to compare the WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal. MATERIALS AND METHODS: Fifty extracted mandibular first premolars with single straight roots were divided into two groups, Group I-WaveOne and Group II-NeoEndo. All samples were scanned with cone-beam computed tomography after the root filling and retreatment procedures. The decrease in the volume of filling material after each retreatment protocol was measured. RESULTS: The mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group II was 5.3, after retreatment in Group I was 2.7, and in Group II was 4.2. The mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was significant (P < 0.05). CONCLUSION: Both systems failed to completely remove gutta-percha. WaveOne was significantly more effective than the NeoEndo retreatment system.
RESUMO
CONTEXT: Natural antioxidants have capacity to neutralize the action of free radicles, therefore, effective in reversal of compromised bond strength. AIMS: The aim of this study was to investigate the effect of three different antioxidant treatments on the bond strength of composite resin to bleached enamel. MATERIALS AND METHODS: Ninety extracted human anterior teeth were divided into five groups: Group I (n = 10) - control group no bleaching, Group II (n = 20) - bleaching with 35% carbamide peroxide gel, Group III (n = 20): bleaching with application of 10% sodium ascorbate, Group IV (n = 20): bleaching with application of 6.5% proanthocyanidin, and Group V (n = 20) - bleaching with application of 50% Aloe vera. These groups were further subdivided into two subgroups based on whether composite buildup was done immediately (Subgroup A) or after a delay of 2 weeks (Subgroup B). Shear bond strength of the specimens was tested under universal testing machine. STATISTICAL ANALYSIS USED: Data were statistically analyzed using Student's unpaired t-test, ANOVA test, and Tukey's Kramer multiple comparison test. RESULTS: The mean bond strength of Group IVA was significantly higher (4.27 ± 1.86) which indicated that immediate application of proanthocyanidin showed higher bond strength after bleaching (P < 0.05). CONCLUSION: Within the limitations of this study, it can be concluded that immediate application of antioxidants on bleached enamel before composite restoration reversed the bond strength of composite restoration. The immediate application of proanthocyanidin proved superior followed by A. vera.
