Effect of CPP-ACP on shear bond strength of composite-resin to bleached enamel

Tooth sensitivity is common after vital tooth bleaching. Desensitizers are available as a component of bleaching agents or separated materials. The aim of this invitro study was to evaluate the effect of “GC tooth Mousse (GCTM)” on bond strength of composite resin to bleached enamel. This experimental study was conducted on 48 freshly extracted sound molars. Samples were divided in 4 groups (n=12). In group 1 (negative control) composite resin was bonded on the buccal enamel surfaces. Specimens in groups 2 and 3 were bleached for 6 hrs/d for 5 consecutive days (Daywhite ACP). Group 2 specimens were immediately bonded with composite resin. In group 3, GCTM was used for 30 min in 5 consecutive days and then rinsed after each procedure. On the 5th day the specimens were bonded using composite resin. In group 4, the specimens only received GCTM and then composite resin cylinders were bonded. After 500 rounds of thermocycling, shear bond strength of the samples were measured and the findings were analyzed by Two-way ANOVA and Tukey-Keramer tests. (α = 0.05) Variance analysis showed significant differences between groups (P = 0.0). The highest and the lowest bond strengths were found in groups 1 and 2 respectively. The Tukey-Keramer analysis showed that using GCTM after bleaching had significant effect on composite shear bonding strength. (P < 0.05) Within limitations of this invitro study, using the GCTM as a desensitizer agent either alone or during bleaching affected the composite resin bond strength to enamel. More investigation is recommended.