High resolution ultrastructural reevaluation of dental cuticle in monkey tooth

In this study the detailed ultrastructure of the dental cuticle at the dentogingival border in monkeys (macaques) was observed. The deciduous molars and permanent premolars with associated gingiva were prepared for thin section electron microscopy. The dental cuticle, seen as a dense amorphous, usually unlaminated layer, was localized between the tooth enamel and the junctional epithelium of the gingiva in close association with the internal basement membrane of the junctional epithelium. High resolution electron microscopy showed that its basic structure was a fine network of irregular anastomosing strands identified as the cord network of the basement membrane which was continuous with that of the lamina densa of the internal basement membrane of the junctional epithelium. In the cuticle. openings of most of the network were filled with a dark amorphous material. These observations suggest that an additional layer of a cord network formed from the basement membrane components, which is probably secreted by the cells of the junctional epithelium during formation of the cuticle, is added to the cord network of the lamina densa of the basement membrane. In addition, a dark amorphous material is deposited within the newly added cord network at the enamel side of the basement membrane. The origin of this dark material still remains to be clarified, but the possibility is that it originates, as has previously been suggested, from either serum protein in gingival exudate or from hemoglobin produced by the degradation of red blood cells.