Experimental Study On Pulp Capping With Recombinant Human Bone Morphogenetic Protein-2 And Collagen I

Objective Vital pulp therapy was the best choice for pulp exposure caused by dental caries,trauma and various operative dentistry. At present, the pulp capping materials used clinically were all not ideal, so it was necessary to explore the better cadidates . An ideal pulp capping agent should conceivably have properties to induce odontoblast differentiation and reparative dentinogenesis and to preserve pulp vitality .It was suggested that a functional network consisting of extracellular matrix molecules and growth factors control odontoblast differentiation and reparative dentinogenesis. Bone morphogenetic protein had been implicated in teeth embryogenesis and hence might play a role in traumatical pulp repair .Type I collagen,a main component of the extracellular matrix in both pulp and dentin, could promote phenotypic expression of odonoblast .This study was aimed to assess the effect of recombinacnt human bone morphogenetic protein-2 (rhBMP-2) combined with type I collagen on reparative dentinogenesis and odontoblast differentiation and to investigate the possible mechanism underlying traumatized pulp repair , which would facilitate the choosing of ideal pulp capping agents. Methods Freshly exposed pulps of thirty cats were capped with four different agents: rhBMP-2/collagen I ,calcium hydroxide, type I collagen and bovine serum albumin as control. The reparative dentinogenesis and osteocalcin content were assessed after 1wk~. 2wk~ 4wk and 6wk by means of histology and isotope radioimmunoassay. Results (1) The dental pulp of the teeth capped with rhBMP-2 /collagen showed mild cellular inflammatory response and odontoblast differentiation with tubular dentin bridge on the exposed site . On the contrary,the pulp in calcium hydroxide group showed moderate to severe cellular inflammatory response with osteodentin formation; (2) 2wk after pulp capping, the BGP content in pulp capped with rbBMP-2/collagen I was 109 6.37pg/mg,which was higher than that of calcium hydroxide ,collagen I and BSA (P