Associations between dental fluorosis of the permanent and primary dentitions

Objectives: Relatively little is known about associations between primary and permanent tooth fluorosis. In this study, associations between dental fluorosis of the permanent and primary dentitions were assessed. Methods: Subjects (n=601) are in the Iowa Fluoride Study, which included fluorosis examinations of the primary and early-erupting permanent dentitions by trained dentist examiners. Relative risks, correlations, and logistic regression assessed associations between permanent tooth fluorosis and primary molar fluorosis. Results: Ten percent had primary molar fluorosis at age 5; 36% had definitive (mostly mild), 28% questionable, and 36% no permanent incisor fluorosis at age 9. Those with primary molar fluorosis were significantly more likely to have definitive permanent incisor fluorosis (76% vs. 32%), and permanent molar fluorosis (59% vs. 16%). The strong association between primary and permanent tooth fluorosis is independent of level of fluoride intake. Conclusions: Detection of primary tooth fluorosis in pre-school children should alert clinicians and parents to the high likelihood of subsequent fluorosis in the permanent dentition.