Abstract
Hypophosphatemic vitamin D-resistant rickets is characterized by familial occurrence, a lowered serum phosphorous level, and disturbance of ossification, which does not respond to the usual therapeutic doses of vitamin D. The clinical picture of vitamin D-resistant rickets is variable and the diagnosis is difficult during the first year of life. Children with this disorder have frontal bossing of the skull, dwarfism affecting the legs more than the trunk, bowed legs and a poorly mineralized skeleton. This disease, when developed later in life, is less severe and may not be characterized by rickets or other osseous deformities. This disease may go undiagnosed during childhood. In the mouth, spontaneous gingival abscesses are frequently noted.
A Japanese boy aged one year and ten months was first seen in the Niigata University Dental Hospital complaining of gingival abscesses in both upper de-. ciduous central incisors and in the lower left deciduous central incisor. The pa- tient's general and family histories were negative, but he had once had a bruise on the anterior part of the mouth. Therefore, the gingival abscesses seemed to be attributed to the bruise. Fourteen months latter, another gin gival abscess was formed at the buccal gingiva of the lower right deciduous central incisor. And then, six months later, a new abscess was found at the gingiva of the upper right deciduous lateral incisor. None of the teeth was attacked by caries. Panoramic X ray films of the patient revealed that all deciduous and permanent teeth had large pulp chambers and these teeth were less calcified. Furthermore, the upper and lower jaws seemed to be poorly developed. These spontaneous gin- gival abscesses and roentogcnorgraphic findings caused us to suspect that the patient had some systemic disease. Therefore, the patient was referred to the Niigata University Medical Hospital for examination. As a result, the patient was diagnosed as having hypophosphatemic vitamin D-resistant rickets.
The findings of this patient were as follows:
1) Bone age and physical growth were retarded, but delayed eruption of the teeth was not observed.
2) A slight frontal bossing was noted on account of retardation of the depth of cranial base and upper jaw.
3) The following dental anomalies were seen.
(1) large pulp chambers and long pulp horns.
(2) pronounced interglobular dentin.
(3) clefts and tubular defects in the dentin of the pulp horn region.
4) Electron probe microanalysis revealed that the dentin was incompletely calcified, and the dentin had low density of magnesium.
5) A preformed crown seems to be preferable for the prophylactic treatment for spontaneous gingival abscess.
