乳中切歯結節, 過剰歯およびその他数種の異常を伴った 1 例

Abstract

We recently encountered a female patient of 3 years of age whose chief complaint was her esthetic deformity owing to the bilateral congenital scars in the upper lip which were treated surgically in our clinic. Beside the above deformity, she had several comblicatious such as incisive tuber of deciduous central incisor, a supernum erary milk tooth, submucosal cleft of jaw-palate and adhesion of the frenulum of upper lip. Search of literatures revealed that so far only about 4 cases of abnormal tuber in deciduous incisor and as few as only 10 cases of supernumerary deciduous tooth were reported. According to Kurosu et al. (1968), the occurrence of incisive tuber of deciduous teeth was one to one thousand, and the occurrence was more frequently in upper jaw than in lower jaw. They also reported that the tuber occurred more frequently in central incisor than in lateral incisor and canine of the deciduous dentition. According to Ogiwara et al. (1967), the incisive tuber was an outcome of abnormal development of the lingual cervical ridge. As to the frequency of supernumerary appearance deciduous tooth, Okamoto (1941) reported that it occurred once in tens of thousands, Ikuta (1925) repoted 2 cases in 23, 600 and Fukada (1957) failed to see any in 10, 149 subjects examined. It should be noted that all these supernumerary tooth, as they appeared in so few instances, occurred in the upper frontal teeth, except that which was reported by Tochihara (1936) to have occurred in the lower frontal teeth. The incisive tuber in the present case appeared as an irregularly formed pyramidal elevation that grew upward from the cervical region of a__-|. The tuber extended to about two third of length of the crown. Radiographic examination revealed that the pulp cavity was extended into the inside of tuber, and the tooth root showed no sign of fusion with other tooth and was single-rooted. The patient also showed jaw cleft between the teeth |<bc>___- and the presence of submucosal cleft of palate was confirmed by means of radio-graphy. The deciduous tooth which was apparently supernumerary, was dislocated lingually, and the tooth |b__- was twisted by 90 degree with its labial side turned toward distal direction. Two theories have been advanced as to possible origin of the supernumeray tooth in the deciduous dentition, of which the one is based on the ontogenetic dysplasia and the other based on the phylogenetic atavism. In view of our findings on the position of the tooth erupted and the shape and size of the tooth itself, we would like to favor the theory advanced by Fujita (1958) for the origin of the supernumerary tooth as being the result of a morphological disturbance that occurred in the dental lamina.