Abstract
Purpose: To investigate the effect of pretreatment protocols involving Papacarie Duo gel and Scotchbond Universal (SU) on the microshear bond strength (mu SBS) of resin composite (RC) to hypomineralised enamel (HE). Materials and Methods: Specimens of normal enamel (NE) and HE were derived from extracted hypomineralised first permanent molars (FPMs). Based on the colour of demarcated opacities, HE specimens were classified as creamy/ white (CW) or yellow/brown (YB). The specimens were randomly allocated into eight groups (n = 20). Each group in-volved pretreatment with Papacarie Duo gel or no pretreatment, and SU applied in etch-and-rinse (E&R) or self-etch (SE) mode. All specimens were bonded with RC and subjected to mu SBS testing. Failure modes were analysed using an optical microscope and SEM. Results: Comparing NE with HE, the following factors were found to be significant (p < 0.001): type of enamel sub-strate, deproteinising pretreatment, and etching mode. Comparing CW HE with YB HE, a significant interaction be-tween "deproteinising pretreatment" and "etching mode" was demonstrated (p = 0.028). When subjected to the concurrent use of Papacarie Duo gel and phosphoric acid etching, HE specimens showed a significant increase in mu SBS (p < 0.001). Conclusion: Deproteinising pretreatment using Papacarie Duo gel followed by the application of SU in E&R mode led to increased mu SBS of resin composite to HE.