Bleached enamel is not conducive to immediate composite restoration. The use of oligomeric proanthocyanidin complexes as antioxidants enables an immediate composite restoration post bleaching. SUMMARYObjective: This in vitro study assessed the neutralizing effect of grape seed extract (oligomeric proanthocyanidin complexes [OPCs]) on the bond strength of bleached enamel. Materials and Methods: 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 (n¼20): bleaching with 38% hydrogen peroxide gel for 10 minutes, without the use of an antioxidant; Group II (n¼20): bleaching followed by the use of 10% sodium ascorbate solution; Group III (n¼20): bleaching followed by the use of 5% proanthocyanidin solution; and Group IV (n¼10): 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 buildup 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.Results: 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.Conclusion: It can be concluded that the use of grape seed extract prior to bonding procedures on bleached enamel completely neutral-*Sampath Vidhya, MDS, senior lecturer,

It can be concluded that dentin surface pretreatment with both 10% sodium ascorbate and 6.5% proanthocyanidin resulted in significant improvement in bond strength of resin composite to deep dentin.

Aim:The objective of this study was to analyze the application of PA agent that improves the bond strength of root dentin treated with NaOCl.Materials and Methods:Group 1: root canals were irrigated using 0.9% isotonic saline as an irrigant (negative control); Group 2: root canals were irrigated using 5.25% NaOCl (positive control); Group 3: root canals were irrigated with 5.25% NaOCl followed by 10% sodium ascorbate for 10 minutes; Group 4: root canals were irrigated with 5.25% NaOCl followed by 5% PA for 10 minutes. All the canals were then coated with self-etch dentin bonding agent, filled with resin cement, stored for one day in water, and then cross sectioned into three slabs of 2-mm thickness that were prepared and tested for microtensile bond strength.Results:The results demonstrated that 5.25% NaOCl caused significant reduction (P<0.05) in the bond strength, but this can be reversed by 5% PA significantly more than the 10% sodium ascorbate.

Objectives:To evaluate the shear bond strength of composite resin to deep dentin, bonded using a self-etch adhesive, after treatment with two collagen cross-linkers at varying time intervals.Materials and Methods:Thirty extracted human incisors were sectioned longitudinally into equal mesial and distal halves (n = 60). The proximal deep dentin was exposed and the specimens were divided based on the surface treatment of dentin prior to bonding as follows: Group I (n = 12, control): No prior dentin surface treatment; group II (n = 24): Dentin surface pretreated with 10% sodium ascorbate; and group III (n = 24): Dentin surface pretreated with 6.5% proanthocyanidin. Groups II and III were further divided into two subgroups based on the pre-treatment time of five and 10 min. Shear bond strength of the specimens was tested using universal testing machine and the data were statistically analyzed.Results:Significantly higher shear bond strength to deep dentin was observed in teeth treated with 10% sodium ascorbate and 6.5% proanthocyanidin compared to control group. No significant difference was observed between 5 min and 10 min pre-treatment times.Conclusion:Dentin surface pre-treatment with both 10% sodium ascorbate and 6.5% proanthocyanidin resulted in significant improvement in bond strength of self-etch adhesive to deep dentin.

Objective:This in vitro study investigated the effect of a desensitizer on the degree of conversion of two bonding resins using Fourier transform infrared (FTIR) spectroscopy.Materials and Methods:An etch-and-rise bonding resin and a self-etching adhesive resin were selected for the study. Vivasens (Ivoclar Vivadent) was used as a desensitizing agent. Grouping was done as follows: Group I: Adper Single Bond (n=10), Group II: Adper Single Bond + Vivasens (n=10), Group III: AdheSE One (n=10), Group IV: AdheSE One + Vivasens (n=10). The bonding resin alone was light cured for 20 seconds in groups I and III. For groups II and IV, 1 ml each of the bonding resin and the desensitizer was mixed in a vial and light cured for 20 seconds. The specimens were analysed using FTIR spectroscopy.Results:Group II (Adper Single Bond + Vivasens) showed a significantly higher degree of conversion compared to Group I (Adper Single Bond). Comparing Groups III and IV, Group IV (AdheSE One + Vivasens) showed a significantly higher degree of conversion compared to Group III (AdheSE One).Conclusions:The degree of conversion is increased when a dentin bonding agent is used along with a desensitizer. Hence, this combination can be recommended to effectively control postoperative sensitivity.