Afibrillar dental cementum in the rat and hamster

Afibrillar cementum “spurs” have been observed as a direct coronal extension of fibrillar root cementum near the cemento‐enamel junction of rat molars. It was also present as a localized deposit over the dentin surface of a hamster mandibular molar near the bifurcation. Adjacent cementicles in the periodontal ligament consisted of an intimate mixture of fibrillar and afibrillar cementum. It is suggested that afibrillar cementum may be due to failure of the collagen moiety to aggregate into fibrils or to a marked relative increase in the glycoproteoglycan content of the organic matrix.