抄録
A patho-histological study has been undertaken on full-length tissue sections of a total of 9 cases of odontomas with reference to their respective clinical manifestation. The findings obtained were summarized as follows. 1) All the tumors included in this study were the 'hard-type' odontoma which appeared within the maxilla or mandible independently and with no direct association with erupted dentition. 2) With 6 cases of the odontomas the structure was studied by the roentogen rays three-dimensionally and the number of the tooth anlage and arrangement of the tooth components were respectively examined. Each of the 3 cases of these consisted of two tooth anlages geminated either at the crown or at the root portions of the teeth. In two cases of the odontoma there was seen complex arrangement of the tooth elements in one individual tooth, and in the last case there was seen an aggregation of a large number of teeth. 3) Based on the number of tooth anlage involved in the formation of individual odontoma and on the patterns of arrangement of the tooth components, the 9 cases of odontoma could be classified in the following manner : 1. Inversive constitutional odontoma with single tooth anlage (3 cases) 2. Root-fused odontoma with 2 tooth anlages (2 cases) 3. Composite odontoma with multiple anlages (2 cases) 4. Crown-fused odntoma with 2 tooth anlages (1 case) 5. Complex odontoma with single tooth anlage consisting mainly of cement substance (1 case)
