Abstract
A nation-wide field survey was undertaken to examine clinical causes for hypoplasia of primary teeth in 141 children above 3 years of age with primary dentition having enamel hypoplasia. The survey was carried out by visual examination, photographic evaluation and questionnaire survey. The controls consisted of 120children without enamel hypoplasia.
The following results were obtained.
1. Hypoplastic teeth due to inflammation, trauma or radiation were not found.
2. Based on the configuration of the hypoplastic teeth, the place of birth and type of nursing, the teeth that developed enamel opacity could not necessarily be regarded as to mottled teeth.
3. No correlation was found between the unbalanced diet of the mothers during pregnancy and the occurrence of the hypoplastic teeth.
4. The development of enamel hypoplasia was estimated to have occurred from the neonatal to infantile stage for the primary canines and from the fetal stage to the early stage of birth or 6 months after birth for second primary molars.
5. Hypoplasia seemed to have begun from the stage of the matrix formation in many cases.
6. Among the mothers during embryogenesis, threatened abortion, severe hyperemesis gravidarum, anemia and drugs used in the treatment of these symptoms seemed to be responsible for the development of hypoplasia. Among the children, diseases occurring within one year after birth, exathematous diseases such as exanthema submonia, common cold and pneumonia, Jaundice, intussusception and asthma seemed to be responsible.
7. The number of enamel-hypoplastic teeth per child increased, as the frequency of diseases in both mothers and children increased.
8. The kind of teeth susceptible to damage, the time of damage, the sensitivity of individuals, and the kind and severity of damage seemed to interact in the etiology of hypoplasia.
