HISTOPATHOLOGICAL ANALYSIS OF REGIONAL ODONTODYSPLASIA

Abstract

Regional odontodysplasia (ROD) is an uncommon localized disorder of tooth development with unknown etiology. It is characterized by defective formation of both enamel and dentin, and formation of calcifications in pulp and dental follicle. Because enamel and dentin are the products of ameloblasts and odontoblasts, respectively, findings in ROD indicate that abnormality occurs in both of these cell types. However, knowledge regarding changes in odontogenic cells in ROD is mostly lacking. Therefore, the purpose of this study was to analyze the histopathological features of odontogenic cells and the characteristic calcifications, presumably the products of the odontogenic cells, in ROD. Clinical information and biopsy materials of 12 ROD cases were analyzed. Three types of calcifications were found in ROD affected teeth: 1) globular basophilic calcifications associated with reduced enamel epithelium (REE); 2) small round calcifications associated with spindle cells arranged in a storiform pattern; and 3) eosinophilic calcifications with globular purple calcified material, previously described as enameloid conglomerates. Odontoblasts in ROD affected teeth were flattened and showed vacuolization. Using Picro Sirius red stain, a histochemical stain for collagen type I and III, the second and the third types of calcifications showed collagen birefringence. Our findings showed that the morphology of odontoblasts in ROD is altered; and support that the globular type calcifications in ROD are dystrophic enamel calcifications, most likely products of REE. It also suggests that enameloid conglomerates are likely the products of stem cells in dental follicle. These findings serve as the basis for further immunohistochemical and/or ultrastructural investigations.