Attachment of cementum on different hydroxylapatite ceramic (HAC) substrata in vivo. A light and electron microscopic study.

The role of substrate surface characteristics for periodontal regeneration was studied in rats. Cementogenesis was initiated by dental follicle cells retained after dissecting out a molar tooth germ in 5-day-old rats. The tooth germ was substituted by a bone replacement material, namely HAC granules of porous consistency. Tissue blocks were removed after 24 weeks and processed for light and electron microscopic examination. On all HAC surfaces a new cementum-like tissue developed, similar to that of natural root surfaces. The results strongly indicate that the exposure of collagen fibers is not essential in order to achieve new periodontal attachment.