Micromorphologic features of dentin in vitamin D-resistant rickets: correlation with clinical grading of severity.

This study was a histological analysis of 20 primary teeth from 5 patients with 3 clinical grades of vitamin D-resistant rickets (VDRR). The results showed that the degree of globular dentin formation in the histological sections may be graded into Grades I-III in increasing order of severity. In Grade I, the amount of globular dentin was less than 50% of the total dentin thickness, and the interglobular spaces were small. By contrast, in Grade III severity, globular dentin extended throughout the entire thickness of dentin, and the interglobular spaces were large. In Grade II severity, the amount of globular dentin was more than half but did not involve the entire dentin thickness. These histologic grades of severity correlated directly with the clinical grades of the patients. In addition, the study found that lack of medical treatment in affected mothers might lead to globular dentin formation in the fetus in-utero. Conversely, adequate phosphate supplementation in a hypophosphatemic mother might prevent the formation of globular dentin in the fetus.