Effect of Microbrush and Paper-Point on Resin-Bond to Root Dentin

Objectives: To evaluate the influence of the sort brush as a carrier of priming-adhesive-adhesive solution and the use of paper points as a remover of the excess of these solutions on the push-out bond strength of resin cement to bovine root dentin. The null hypotheses were that the sort of brush and the use of paper points do not affect the bond strength. Methods: The canals of eighty single-root bovine roots (16mm in length) were prepared at 12mm using the preparation drill (FRC Postec Plus, Ivoclar). Half of each root was embedded with acrylic resin and the specimens were allocated into eight groups, considering the factors “sort of brush” (4 levels) and “paper point” (2 levels) (n=10): Gr1- small microbrush (Cavi-Tip, SDI); Gr2- Microbrush (Dentsply); Gr3- Endobrush (Bisco); Gr4- convencional brush (Bisco); Gr5- Cavi-Tip (SDI) + paper points; Gr6- Microbrush (Dentsply) + paper points; Gr7- Endobrush (Bisco) + paper points; Gr8- conventional brush (Bisco) + paper points. The root dentin was treated with a multi-step total-etch adhesive system (All Bond 2). The adhesive system was applied using each microbrush, with and without using paper points. One fiber post was imprinted with addition silicon and 80 posts were made of resin cement (Duolink). The resin posts were luted (Duolink resin cement), and the specimens were stored (24 h, water at 37°C). Each specimen was cut in 4 samples (1.8mm in thickness), which were submitted to the push-out test. Results: The sort of brush (P<0.0001) (small microbrush > microbrush = endobrush = conventional brush) and the use of paper points (P=0.0001) (with > without) influenced the bond strength significantly (ANOVA 2-way). The null hypotheses were rejected. Conclusions: The smallest brush (Cavi-Tip) and the use of paper points improved significantly the resin-bond to bovine root dentin.