Impact of Different Antioxidants on the Bond Strength of Resin-based Composite on Bleached Enamel—An In Vitro Study

Abstract

Aim:The aim of this in vitro investigation was to assess the impact of various anti-oxidants namely 5% proanthocyanidin, 10% sodium ascorbate, 10% alpha tocopherol, and 10% green tea on the bond strength of resin-based composite on bleached enamel. Materials and methods:One hundred twenty human maxillary central incisors which were freshly extracted for periodontal reasons, having intact labial surface were us ed in this study. Specimens were randomly divided into six groups (n = 20). Group A: negative control-no bleaching treatment, group B-positive control -bleaching, group C-bleaching + 5% proanthocyanidins, group D-bleaching +10% green tea, group E -bleaching +10% alpha -tocopherol, group F-bleaching + 10% sodium ascorbate. Surfaces were etched followed by application of total-etch bonding system, and composite resin cylinders were bonded. Specimens were tested for shear bond strength using the universal testing machine . Statistical analysis used:The data obtained were subjected to ANOVA and post hoc Tukey's test for statistical analysis.Results: After using bleaching agents and antioxidants for the different groups, Group A has the highest bond strength and group B has the lowest bond strength. Amongst the antioxidants group D showed significantly higher bond strength as compared group C, group E, and group F.Clinical significance: Use of antioxidants instantly following the bleaching procedure and before resin bonding reverses the compromised bond strength of composite resin on bleached enamel without sitting tight for a time of one day to one month. Conclusion:Bleaching of enamel reduced the shear bond strength. All the antioxidants used in this study increased the bond strength of bleached enamel. Among the antioxidant groups, green tea extract showed significantly higher bond strength compared to proanthocyanidin, tocopherol, and sodium ascorbate.

Does the Elapsed Time from Bleaching and the Use of Sodium Ascorbate Influence the Bond Strength of Resin Cement to Bleached Enamel?

“…It is well-documented in the scientific literature that adhesive bond strength values are reduced after tooth bleaching [ 5 , 6 , 10 , 12 ]. Strategies are developed in an attempt to reestablish adequate values of bond strength, such as a time interval between bleaching and the adhesive procedure, as well as the use of antioxidants [ 6 , 11 , 14 ].…”

“…Although not strongly recommended, in some circumstances, the patient cannot wait for this delay, and restorative procedures should be performed immediately or after 24 h with post-bleaching treatment. Antioxidant agents have been tested in an attempt to reduce or eliminate the oxygen content of the dental substrate, recovering totally or partially the initial values of bond strength [ 4 , 5 ]. The acid ascorbic salt SA is a well-known antioxidant due to its capacity to reduce oxidative compounds [ 4 ].…”

“…A thickness of 1 mm was applied and checked with a periodontal probe. The gel remained on the enamel surfaces for 10 min and was agitated with the microbrush point once per minute [ 5 ]. Then, the SA gel was washed off, and the specimens were air-dried and stored in artificial saliva.…”

“…The decreased bond strength of bleached enamel has been cited in the literature [ 5 , 6 ]. Nevertheless, the original values may be recovered when adhesive procedures are postponed [ 4 , 6 ].…”

“…Therefore, solutions to this shortcoming and alternatives to avoid postponing the adhesive restorative procedures have been sought [ 8 ]. Several studies have focused on direct restorative systems [ 4 , 5 ], and little data regarding adhesive cementation is available [ 3 ].…”