Collagen phagocytosis by cementoblasts at the periodontal ligament-cementum interface.

The periodontal ligament-cementum interface of rat first molars was investigated by electron microscopy. Evidence supporting cementoblast phagocytosis of collagen fibrils of the periodontal ligament was found. In addition, collagen-containing vacuoles were frequently observed within cementoblasts in association with an acid phosphatase activity. The presence of acid phosphatase activity in these vacuoles suggested that intracellular degradation of collagen was occurring. Our results showed that cementoblasts exhibited collagen phagocytic activity and suggest that cementoblasts may play an important role in the physiological remodeling and metabolic breakdown of the collagen at the periodontal ligament-cementum interface.