Journal of Dental Specialities

To evaluate the effect of application of two anti-oxidants, sodium ascorbate and grape seed extract after bleaching on the shear bond strength (SBS) of ceramic brackets.

Fifty freshly extracted human first premolars for orthodontic purposes were collected and randomly divided into five groups (n=10 per group), an unbleached control group (Group I) and four experimental groups bleached with 35% hydrogen peroxide as follows: Group II (immediate bonding post-bleaching), Group III (delayed bonding), Group IV (bleaching followed by application of 10% sodium ascorbate solution, then bonding) and Group V (bleaching followed by application of grape seed extract, then bonding). Polycrystalline ceramic brackets were bonded to all the teeth. Bond strength was tested with a Universal testing machine following debonding.

Analysis of variance indicated a significant difference between SBS of the groups (p<0.001). The highest values for bond strength were measured in Group V (12.68±0.2) and the lowest in Group II (6.92±0.85). Group II (immediate bonding) had significantly lower bond strength than all the other groups. There was no significant difference between the SBS of Groups I, III, IV and V. Adhesive Remnant Index (ARI) scores indicated bond failure at the bracket/adhesive interface and within the adhesive.

Bleaching with 35% hydrogen peroxide significantly reduced the bond strength of ceramic brackets. Treating the bleached enamel surface with 10% sodium ascorbate solution or grape seed extract (5% proanthocyanidin solution) before bonding, reverses the reduction in bond strength and can be used as an alternative to delayed bonding.