Evidence in favor of an anti-invasion factor in cementum or periodontal membrane of human teeth.

A casein-agar method for the detection of protease inhibitors has been used on human teeth. Periodontal membranes or cementum have been shown to contain a potent collagenase inhibitor. This inhibitor might explain why the roots of teeth are normally protected against resorption. A similar protease inhibitor has recently been demonstrated in cartilage and there it was called an anti-invasion factor.