Introduction: The major side effect of orthodontic treatment is orthodontically induced root resorption (OIRR). Fluoride was previously shown to reduce the volume of the root resorption craters on rats. However, the effect of fluoride on OIRR and repair process in humans has not been investigated. The aim of this study was to investigate the effect of fluoride on OIRR and its repair under light (25g) and heavy forces (225g) on patients who had high and low systemic intake from birth.
Methods: The sample consisted of 98 maxillary premolars in 49 patients who were selected from two different cities which have fluoride concentration of 2ppm and 0.05 ppm, respectively in public water and required bilateral maxillary premolar extractions as part of their orthodontic treatment. The patients were separated into 4 different groups; Group1 High-Fluoride-Intake (2ppm) and Heavy-Force (225g) (13 patients), Group2 Low-Fluoride-Intake (0.05ppm) and Heavy-Force (12 patients), Group3 High-Fluoride-Intake and Light-Force(25g) (12 patients) and Group4 Low-Fluoride-Intake and Light-Force (12 patients). Light or heavy buccal tipping orthodontic forces were applied on upper first premolars for 28 days. After 28 days of tooth movement first premolar on one side was extracted and the contralateral side was extracted after 56 days of retention.
Results and Conclusion: The volume of root resorption craters was reduced in average in High Fluoride groups after 28 days of force application but this reduction is not statistically significant. However, the volume of the resorption craters was found significantly less in high fluoride groups after 56 days of retention (P>.05).