Short resin-posts bonding to primary dentin. Microleakage and micromorphological study

Objectives: The aim of this in vitro study was to evaluate the adhesion of two bonding systems (Single Bond, 3M ESPE and Adper Prompt L Pop, 3M ESPE) to short resin-posts in the root canal dentin of primary teeth. Methods: Twenty primary upper and lower canines were endodontically treated following UFSC's protocol and divided into two groups (n=10). In Group 1 the prepared root canals were acid-etched and the Single Bond (3M ESPE) adhesive was used and in Group 2 the adhesive Adper Prompt L Pop (3M ESPE) was used. Resin-posts and cores were built with the composite resin Filtek Z250 (3M ESPE). The specimens were thermo-cycled (500 cycles, 5° and 55°C) and immersed in a 0.5% basic fucsin dye for 24 hours. Then teeth were longitudinally sectioned in a mesial-distal direction for leakage reading. A descriptive analysis of the resin-dentin interdiffusion zone, resin tags and gaps was made by scanning electronic microscope (SEM). Results: Statistical analysis (Mann-Witney) revealed that there were no statistically significant differences between the materials (p= 0.75), but the Single Bond group presented a wider resin-dentin interdiffusion zone (RDIZ) than the Adper Prompt L Pop group. Both groups showed long resin tags formation. Conclusion: It was concluded that besides Single Bond system produced a wider adhesive interface, leakage levels occurred in both groups.