Biocompatibility of three adhesive systems

Objectives: The aim of this in vivo study was to evaluate the biocompatibility of three adhesive systems and a hard-setting calcium hydroxide cement. Methods: Sixty polyethylene tubes filled with the experimental dental materials which were hand-mixed or light-cured according to manufacture´s recommendations: Group 1: Prime & Bond NT (PB – DENTSPLY); Group 2: Bond 1 (BO – JENERIC/PENTRON); Group 3: Optibond Solo (OP – KERR); and Group 4: Calcium Hidroxide – Dycal (CH – DENTSPLY). The materials were implanted into connective tissue of rats. After 15, 30 and 60 days, the implants were surgically excised and the animals killed. Following fixation for 48 hours in Karnovsky (pH 7,2) the specimens were processed for microscopic examination. Sections of 6 mm thickness were stained with hematoxylin and eosin and Masson’s trichrome. Results: At short-term evaluation (15 days) the bonding agents elicited a moderate-intense inflammatory connective reaction. Several venules, macrophages and a few giant cells adjacent to the tube openings gave rise to a thick capsule. These histological findings were less significant to OP. On the other hand, a discrete inflammatory reaction associated with thin fibrous capsule was observed to CH. With time, the connective healing was observed for all dental materials even through many specimens exhibited a persistent inflammatory reaction mediated by macrophages and giant cells. In group 4 (CH) complete healing associated to a thin fibrous capsule was observed at 30 days. Conclusion: It was concluded that all experimental dental materials evaluated were successfully walled off by the connective tissue of the rat. However, CH was less irritant and better tolerated by the connective tissue than the experimental bonding agents which may release their components triggering a persistent inflammatory reaction.