Hard tissue formation in odontogenic lesions associated with impacted tooth: Plausible pathogenesis.

Odontogenesis is a complex process, which involves the molecular interaction between the epithelium and ectomesenchyme called as epithelium mesenchymal interaction (EMI). Reduced enamel epithelium (REE) after tooth formation protects enamel from coming in contact with adjacent ectomesenchyme. Also, REE acts as a source of origin for odontogenic lesions, during the process of development of a lesion, disruption in REE may occur and lead to formed enamel coming in contact with adjacent ectomesenchyme leading to the formation of cementum like calcifications. REE may play a role in pathogenesis of hard tissue formation in odontogenic lesions.

Odontogenic tumors: A 35-year retrospective study of 250 cases in an Indian (Maharashtra) teaching institute.

CONTEXT: This retrospective study was planned to ascertain the relative frequency of odontogenic tumors (OTs) in an Indian population in the light of the latest World Health Organization (WHO) classification. AIM: To compare data with various reports from other parts of the world. STUDY DESIGN: Retrospective study. MATERIALS AND METHODS: The histopathology records and archived slides of all lesions diagnosed as "OT" in the Department of Oral Pathology and Microbiology of Government Dental teaching institute, Mumbai, Maharashtra, India, were recovered from the period January 1981-December 2016. A total of 250 lesions thus classified were reviewed for age, gender, site of tumor, and histopathologic typing. The tumors were reclassified according to the WHO 2017 criteria. STATISTICAL ANALYSIS: Microsoft Excel 2010 was used for statistical analysis. RESULTS: In all, 250 cases of OTs were reported in a 35-year period. OTs in this study constituted 7.14% of all the 6797 registered biopsies. The most frequent histological type was ameloblastoma (AML) (30.8%), followed by odontoma (19.2%), unicystic ameloblastoma (18.4%), adenomatoid OT (14%), cementifying fibroma (6%), odontogenic myxoma and cementoblastoma (2.4% each), calcifying epithelial OT and odontogenic fibroma (2% each), ameloblastic fibroma (1.2%), squamous OT, dentinogenic ghost cell tumor, peripheral ameloblastoma, ameloblastic carcinoma and ameloblastic fibrosarcoma (odontogenic sarcoma) (0.4% each). CONCLUSION: A frequency of 7.14% of OTs was observed in this study. AML comprised the single most common tumor of all OTs. This study observed geographic variations in the frequency and distribution of OTs.