Abstract
The following conclusions were drawn as a result of observation over a period of years on the same infants from age three when deciduous dentition was complete, with the purpose of regarding supernumerary mediodens on the maxilla. A survey made on the development condition, root resorption, change in position of the supernumerary teeth, and the effect on deciduous dentition and permanent dentition.
1. Out of 152 three-year-old children, those with supernumerary teeth amounted to five males and two females making a total of seven children, which was a 4.6% occurrence rate.
2. Of the above seven cases, one child had a supernumerary tooth. As for the impaction condition, two out of eight teeth normal impaction while six teeth had inverted impaction.
3. In one case the root development of a supernumerary tooth was completed at three year of age, but with the rest of the children the root was incomplete. Out of the incomplete root cases of incomplete growth, except for the two cases where the tooth was extracted during observation, the roots in all other cases were observed to be completed between the age of six to seven.
4. Categorizing the supernumerary teeth based on the root growth condition of normal deciduous teeth and permanent teeth, a tooth which had a complete root in child three years old was considered to be a supernumerary deciduous tooth. However, a tooth which had an incomplete root at age six to seven was considered to an supernumerary permanent tooth.
5. There were six supernumerary teeth, the positions of which changed during the observation; two teeth changed their axial inclination, and four teeth moved towards the apical side or occlusal side.
6. As for the root resorption of supernumerary teeth, there was one case judged as a supernumerary deciduous tooth in which the root was completely resorpted. On the other hand, there were just a few cases judged as supernumerary permanent teeth in which the root was partly resorpted.
7. Interference of the supernumerary mediodens on the maxilla to deciduous teeth, permanent teeth, dentition or the alveolar part exists temporarily, but this was nominal with longitudinal observation.
