Root surface conditioning with bone morphogenetic protein-2 facilitates cementum-like tissue deposition in beagle dogs.

BACKGROUND AND OBJECTIVE Modification of the root surface may play an important role in regenerating the periodontal attachment between the root and periodontal connective tissue. We speculated that bone morphogenetic protein (BMP) application to the root surface constructed a novel attachment by cementum-like hard tissue, although gingival connective tissue proliferated to the root surface. The aim of this study was to examine whether BMP-2 guided cementum-like tissue deposition on a BMP-conditioned root surface. MATERIAL AND METHODS Root dentin on the buccal side of 24 teeth in four beagle dogs was surgically exposed. The denuded root dentin surfaces were demineralized with EDTA and washed with saline. Subsequently, 15 microL of BMP-2 solution (loading dose, 0.4 and 1.0 microg/microL) was applied to the root dentin surface. In the control roots, phosphate-buffered saline was applied to the root surface. Specimens were analyzed histologically 16 wk after surgery. RESULTS Formation of cementum-like tissue was frequently observed on the BMP-2-conditioned root at the coronal portion. Cellular cementum-like tissue was separated from the original cementum and encapsulated with gingival connective tissue. Cementum-like tissue formation with BMP-2 at 1.0 microg/microL was significantly greater than that in the control roots and those with BMP-2 at 0.4 microg/microL. Downgrowth of the junctional epithelium in the 1.0 microg/microL BMP-2 group was significantly less than that in the control roots. CONCLUSION Root dentin surface conditioning with BMP-2 stimulated cementum-like tissue formation and inhibited epithelial downgrowth.