Evaluation of the Effect of Different Antioxidants on Resin Bond Strength to Enamel after Bleaching: An In Vitro Study.

AIM: To compare and evaluate the efficacy of 10% sodium ascorbate (SA) solution, 10% alpha-lipoic acid (ALA) solution, 10% propolis solutions (PLS), and 10% pomegranate peel extract (PPE) solution on the shear bond strength (SBS) between composite resin and bleached enamel after 60 minutes. MATERIALS AND METHODS: Ninety extracted teeth were divided into 6 subgroups (n = 15) based on the antioxidant applied: Group I: Bleaching + application of 10% SA solution for 60 minutes. Group II: Bleaching + application of 10% ALA solution for 60 minutes. Group II: Bleaching + application of 10% PLS for 60 minutes. Group IV: Bleaching + application of 10% PPE solution for 60 min. Group V: Positive control (PC) bleaching without antioxidant application. Group VI: Negative control (NC) specimen neither subjected to bleaching nor application of an antioxidant solution. About 35% hydrogen peroxide (HP) was used for bleaching the labial surfaces in the groups considered. Labial surfaces were then bonded with composite using a customized cylindrical mold followed by storage in distilled water for 24 hours and shear bond strength was tested using universal testing machine. RESULTS: The mean shear bond strength values for groups I, II, III, IV, V, and VI are 5.04, 2.29, 5.02, 4.07, 1.42, and 9.08 respectively. The peak shear bond strength value is obtained for the negative control group; whereas the lowest mean SBS value is obtained for the positive control group. CONCLUSION: All herbal extracts used in the present study have demonstrated a reversal of reduced SBS between resin composite and bleached enamel surface. CLINICAL SIGNIFICANCE: The reduction in bond strength of adhesive restorations was conventionally overcome by delaying the bonding procedure for a specified period resulting in prolonged treatment duration and multiple appointments. Sodium ascorbate is most commonly used but it is postulated to form a porous scaffold capable of harboring bacteria. Herbal antioxidants are gaining popularity in this regard as they are naturally derived, effective and affordable phytochemicals in addition to being viable alternatives against drug-resistant strains of microorganisms.

An in vitro Investigation of the Sealing Ability of Biodentine and Mineral Trioxide Aggregate as Retrofilling Materials after the use of Various Irrigating Solutions.

Aim: The purpose of this study was to assess the sealing ability of Biodentine (BD) and mineral trioxide aggregate (MTA) as retrograde filling materials after irrigation with 17% ethylenediaminetetraacetic acid (EDTA) and QMix irrigating solutions. Materials and Methods: Decoronation of 48 permanent maxillary central incisors was done. Root canal instrumentation was carried out in the samples. The apical root was resected for about 3 mm and retrocavities were prepared. Teeth were allocated into two groups (n = 24). MTA was used in Group 1. BD was used in Group 2. Depending on irrigation, the groups were subdivided A, B, and C subgroups. Group A - 0.9% saline; Group B - 17% EDTA; and Group C - QMix were used. The resected root end was irrigated with 5 ml of all irrigating solutions for 1 min. After final irrigation, cavities were filled with retrofilling materials in each group. Nail enamel was applied to the surfaces of the roots apart from the resected end. Roots were placed in India ink for 72 h. Teeth were sectioned longitudinally and microleakage was determined with a stereomicroscope. Statistical Analysis: Analysis was done using the one-way analysis of variance, Independent t-test, and post hoc test. Results: Statistically significant difference in the degree of microleakage was observed between irrigating solutions and the retrofilling materials. Conclusion: BD exhibits a better sealing ability compared to MTA as a retro filling material following QMix irrigation.

Apical Extrusion of Intracanal Bacteria following use of Two Engine-driven Instrumentation Techniques: An in vitro Study.

AIM: The aim of the present study was to compare in vitro the amount of debris extruded apically from extracted teeth, using Twisted files and ProTaper rotary during two different instrumentation systems. MATERIALS AND METHODS: Forty-five human single-rooted mandibular premolar teeth were randomly divided into three groups and contaminated with Enterococcus faecalis. The teeth in experimental groups were instrumented until reaching the working length with ProTaper rotary instruments and Twisted files with XSmart and XSmart Dual groups. Debris extruded from the apical foramen was collected into glass vials and the amount of bacteria was calculated. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with p = 0.05 as the level for statistical significance. RESULTS: The XSmart Dual group extruded comparatively lesser bacteria compared to the XSmart group. Lesser amount of bacterial extrusion was seen when Twisted files were used compared to the ProTaper files (p < 0.05). CONCLUSION: Under the circumstances of this in vitro study, it can be concluded that all instrumentation techniques produced measurable apical extrusion of debris. So, it is upon the practitioner to decide which system best fits their individual needs and their level of skill and experience that will provide the best possible endodontic care for our patients. CLINICAL SIGNIFICANCE: The newer instrument designs, including noncutting tips, different cross sections, radial lands, and variable tapers, are better for the clinicians to improve working safety, to reduce the working time, and to create a greater flare within the preparations.