Histological observations of teeth and peridental tissues in cleidocranial dysplasia imply increased activity of odontogenic epithelium and abnormal bone remodeling.

Cleidocranial dysplasia (CCD) is a heritable generalized bone dysplasia presenting with a variety of dental abnormalities. To delineate morphological features of the dental tissues, we have analyzed histologically the structure of teeth and peridental tissues obtained from four CCD patients. Dentin appeared regular, except when formed in response to caries, physiological attrition or root resorption. Both acellular and cellular cementum were present in deciduous teeth, whereas in permanent teeth, cellular cementum was virtually lacking and acellular cementum was partially hyperplastic. Enamel pearls were seen in the furcations of one deciduous and one permanent molar. The roots of most deciduous teeth were resorbed only to a slight extent. Morphologically, supernumerary teeth resembled their normal counterparts. Denticles as well as epithelial cell clusters were occasionally present in the root pulps of deciduous teeth. In the peridental tissues, epithelium was locally abundant, and the cytokeratin profile confirmed its odontogenic origin. While the organization pattern of the alveolar bone matrix related to unshed deciduous teeth and unerupted permanent teeth varied, woven bone was abundant. Both formative and resorption surfaces were seen. Also, reversal lines were prominent, suggesting that the bone had, in fact, undergone remodeling. While no direct association between the aberrant bone morphology and the multifarious histological abnormalities of dental tissues can be established, the local abundance of odontogenic epithelium in peridental tissues of developing/unerupted as well as fully developed teeth may be causally related to the formation of excess acellular cementum, enamel pearls and supernumerary teeth.