Abstract
In order to clarify the relationship between the periapical inflammation of the deciduous tooth and the permanent tooth germ,74 cases (ranging from 3-9 years of age) that had periapical radiolucency of the mandibular deciduous molar on one side and did not have caries on the other side of the same dentition, were investigated and reportec in a previous paper, Part I. In 28 cases that were followed up over a period of from one to nine years, the developmental stages, the timing of eruption and the enamel hyopplasia of the permanent teeth were observed.
The results are as follows.
1) The following was found in the cases with extraction of the infected deciduous teeth.
(i) The periapical inflammation of deciduous teeth with or without the avoidance phenomenon of the tooth germ of the permanent successors did not influence the eruption of the permanent teeth.
(ii) There was a tendency that the permanent successor where the deciduous tooth was extracted erupted earier than the control tooth when the eruption space was sufficient.
(iii) In 12 of 19 teeth, the speed of development of the tooth germ of the permanent successor where the deciduous tooth was extracted was as fast as that of the permanent control tooth even after extraction. However, the development of the permanent successor under the infected deciduous tooth was advanced with 5 of the teeth, and delayed with 2 of the teeth.
2) In three of the six cases that could be followed up by the time of eruption of both sides of the permanent teeth, the infected side and the control, the enamel hypolasia of the permanent successor resulted from the periapical lesion of the deciduous tooth. The enamel hypolpasia was found on the cervical portion of the buccal surface, and buccal and lingual cusps. Brown stain was found in one tooth.
