Effect of grape seed extract on the bond strength of bleached enamel

This in vitro study assessed the neutralizing effect of grape seed extract (oligomeric proanthocyanidin complexes [OPCs]) on the bond strength of bleached enamel.

Labial enamel surfaces of 70 extracted human maxillary central incisors were randomly divided into four groups based on the antioxidant used as follows: Group I (n=20): bleaching with 38% hydrogen peroxide gel for 10 minutes, without the use of an antioxidant; Group II (n=20): bleaching followed by the use of 10% sodium ascorbate solution; Group III (n=20): bleaching followed by the use of 5% proanthocyanidin solution; and Group IV (n=10): control group in which no bleaching was done. Groups I, II, and III were further subdivided into two subgroups of 10 teeth each, based on whether composite build-up was done immediately (subgroup A) or after a delay of 2 weeks (subgroup B) post bleaching. Shear bond strength of the specimens was tested under a universal testing machine. The data were tabulated and statistically analyzed.

Significantly higher shear bond strength values were observed in teeth treated with 10% sodium ascorbate (Group II) and 5% proanthocyanidin (Group III) as compared with the control group (Group IV). Among the antioxidants used, teeth treated with proanthocyanidin showed significantly higher shear bond strength values than those treated with sodium ascorbate.

It can be concluded that the use of grape seed extract prior to bonding procedures on bleached enamel completely neutralizes the deleterious effects of bleaching and increases the bond strength significantly.