Anatomic relationship of the genial tubercles to the dentition as determined by cross-sectional tomography.

PURPOSE: This study determined the anatomic location and the dimensions of the genial tubercles in relation to the apices of the mandibular central incisors. MATERIALS AND METHODS: Linear cross-sectional tomographic images were made of 41 adult human skulls. A 2-mm-thick section was produced through each central incisor. The vertical distance between the apex of each central incisor and the level of the superior aspect of the genial tubercle was measured on the radiographs. Additional measurements were taken on the dry skulls to determine the horizontal distance between the apices of the two central incisors and the width and height of the genial tubercle. RESULTS: Although 5 mm is considered a safe zone for geniotomies, 29 of the genial tubercles (35.4%) were less than 5 mm from the apices of the mandibular central incisors. The distance between the apices of these incisors ranged from 9 mm to 15 mm. CONCLUSION: Osteotomy of the genial tubercles can be performed within the confines of the mandibular central incisors, but care must be taken to avoid the root apices.

Clear cell neoplasm.

We are reporting four cases of clear cell neoplasm. Local infiltration and destruction was observed in one case while in a second case, originating in the sublingual gland, metastasis to the lymph nodes occurred. The behaviour of these neoplasms has prompted the suggestion that these tumours be designated carcinomas rather that noncommittally tumours or neoplasms (Batsakis and Regezzi, 1977). The histopathological characteristics of our four cases conform to those that have been articulated and believed to be the distinctive features of these tumours (Batsakis and Regezzi, 1977). It is hoped that ours and similar reports will be helpful towards clearing the diagnostic and taxonomic confusion regarding these tumours.