Histopathologic study on pulp response to single-bottle and self-etching adhesive systems

This study compared the pulp response to seven adhesive resins (three single-bottle and four self-etching primers) and their companion resin composite systems with a commercial calcium hydroxide material when applied to exposed monkey pulps. The control group was capped with Dycal (DY), while the experimental groups were capped with one of the following adhesive resin systems: AQ Bond (AQ), Single Bond (SB), Imperva Fluorobond (IF), One Step (OS), Prime&Bond NT (PBNT), Perme Bond F (PBF) and One-up Bond F (OBF). Histopathologic evaluation of pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation and bacterial penetration at the 3rd, 30th and 90th post-operative days was done using light microscopy. Data were analyzed using the Kruskal-Wallis test followed by the Least Significant Difference Test to determine differences between the control group and the experimental groups at each observation period. The correlation of inflammatory cell infiltration and bacterial presence was investigated by the Kendall correlation analysis. All tests were performed at a 95% level of confidence. The pulpal responses of groups DY, SB, OS, PBF and OBF were generally characterized by none-to-mild pulp tissue disorganization and inflammatory cell infiltration. Also, initiation of reparative dentin formation was found earlier in Group DY, resulting in more complete dentin bridges at the 30- and 90-day observation periods. Groups AQ, IF and PBNT had significantly more inflammatory cell infiltration and a lower incidence of reparative dentin formation than Group DY. A significant correlation was detected between inflammatory cell infiltration and the presence of bacteria. It is concluded that the pulp response to SB, OS, PBF and OBF is not significantly different from the calcium hydroxide preparation. However, calcium hydroxide capping resulted in a higher incidence and faster rate of reparative dentin formation.