AFM study of the effects of collagenase and its inhibitors on dentine collagen fibrils

ObjectiveThis study evaluated the effects of exogenous collagenase and two collagenase inhibitors on the variation in microstructure of human collagen fibrils.MethodsDentine specimens which were sectioned from 6 freshly extracted human caries-free third molars were wet polished. Each specimen was divided into 4 parts which were treated as experimental groups (group 1, group 2, group 3) and the control group, respectively. All the specimens were etched and further treated with NaClOaq. Subsequently, the topography of each specimen was observed using atomic force microscopy (AFM) in tapping mode in air. Group 1 was then treated with a solution of collagenase II. Group 2 was treated with a solution of collagenase II and chlorhexidine (saturated solution). Group 3 was treated with a solution of collagenase II and captopril (0.3%). The control group was treated with a buffer solution. After 3 h and 6 h of treatment, the topography of the collagen fibrils was measured with AFM in air, respectively.ResultsAFM images of the dentine collagen fibrils were obtained after treatment with NaOClaq. Following further treatment with collagenase II, the topography of the collagen fibrils changed. Most reticular collagen fibrils disappeared after 6 h. After treatment with collagenase II in the presence of chlorhexidine or captopril for 3 h and 6 h, the morphology of the collagen fibres was not changed obviously.ConclusionsExogenous collagenase II effectively degraded human dentine collagen fibrils, and its collagenolytic activity was inhibited by the exogenous collagenase inhibitors, chlorhexidine and captopril.