TRABECULAR BONE-FORMATION IN THE HEALING OF THE RODENT MOLAR TOOTH EXTRACTION SOCKET

The aim of this study was to investigate the nature of the template st ructure on which trabecular bone formation occurs during healing of th e rodent tooth extraction socket, a well studied bone healing system, The presence of collagen type LI mRNA has previously been described in the healing socket, although the formation of the protein or cartilag e has not been observed, However, recent evidence from developmental a nd other bone healing studies indicates that collagen type III may be important in forming the preliminary scaffold on which bone trabeculae are formed, The maxillary right molar teeth were removed from rats un der general anaesthesia and the animals killed at various times afterw ard, The tissues were examined using histological, in situ hybridizati on, and immunohistochemical staining techniques, It was concluded that collagen type IIA mRNA was produced by osteoblast cells of the socket , but that collagen type II, if present would account for less than 0. 01% of the total proteins extracted, During bone formation, Sharpey's fibers were seen radiating from the peripheral bone toward the center of the socket, These optically active collagen fibers were inserted in to the forming bone trabeculae and were recognized by antibodies raise d against collagen type III, The arrangement and composition of these fibers therefore suggest that they form a preliminary framework on whi ch deposition of woven bone trabeculae occurs.