Scanning electron microscopy analysis of microstructure of the adhesive interface between resin and dentin treated with papain gel.

ABSTRACT

Aim: The aim of this in vitro study was to observe and compare the microstructure of the adhesive interface between resin and dentin treated with Papacarie® using scanning electron microscopy (SEM). Materials and Methods: Totally, 10 human dentin slabs were randomly distributed into two groups. The control group (n = 5) was subjected to etching with 37% phosphoric acid for 20 s and washed for 30 s, dried with absorbent paper, and the bonding agent was applied along with low viscosity resin. In turn, the experimental group (n = 5) was subjected to the same procedure, but Papacarie® (Fórmula and Ação, São Paulo, Brazil) was added for 30 s prior to etching. Adper™ Single Bond 2 (3M ESPE, São Paulo, Brazil) adhesive was applied to both groups following manufacturer instructions. The specimens were prepared for observation under SEM with ×1.000, ×2.000, ×2.200 and ×5.000 magnification. The micrographs were evaluated with respect to the formation of the hybrid layer, thickness, shape and length of the tags and microtags. Results: In the experimental group there was the formation of more fine hybrid layer and tags with average of similar length to the control group; microtags in less number and without formation of lateral branches. The resin tags presented conical, smooth and uniform characteristics. Conclusions: When Papacarie® was used prior to the application of a bonding agent it could interfere with the formation of the hybrid layer without changing the length of the tag. Moreover, the morphology in the experimental group was found to be more uniform and regular.