Effect of fluoride on root resorption following heavy and light orthodontic force application for 4 weeks and 12 weeks of retention.

OBJECTIVE: To evaluate the null hypothesis that fluoride intake via drinking water has no effect on orthodontic root resorption in humans after orthodontic force application for 4 weeks and 12 weeks of retention. MATERIALS AND METHODS: Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from two cities in Turkey. These cities had a high and low fluoride concentration in public water of ≥2 pm and ≤0.05 pm, respectively. The patients were randomly separated into four groups of 12 each: group 1HH, high fluoride (≥2 ppm) and heavy force (225 g); group 2LH, low fluoride (≤0.05 ppm) and heavy force; group 3HL, high fluoride and light force (25 g); and group 4LL, low fluoride and light force. Light or heavy buccal tipping force was applied on the upper first premolars for 28 days. At day 28, the left premolars were extracted (positive control side); the right premolars (experimental side) were extracted after 12 weeks of retention. The samples were analyzed with microcomputed tomography. RESULTS: On the positive control side, under heavy force application, the high fluoride groups exhibited less root resorption (P  =  .015). On the experimental side, it was found that fluoride reduced the total volume of root resorption craters; however, this effect was not statistically significant (P  =  .237). Moreover, the results revealed that under heavy force application experimental teeth exhibited more root resorption than positive control groups. CONCLUSION: The null hypothesis could not be rejected. High fluoride intake from public water did not have a beneficial effect on the severity of root resorption after a 4-week orthodontic force application and 12 weeks of passive retention.

Physical properties of root cementum: part 20. Effect of fluoride on orthodontically induced root resorption with light and heavy orthodontic forces for 4 weeks: a microcomputed tomography study.

INTRODUCTION: The major side effect of orthodontic treatment is orthodontically induced inflammatory root resorption. Fluoride was previously shown to reduce the volume of the root resorption craters in rats. However, the effect of fluoride on orthodontically induced inflammatory root resorption in humans has not yet been investigated. The aim of this study was to investigate the effect of high and low amounts of fluoride intake from birth on orthodontically induced inflammatory root resorption under light (25 g) and heavy (225 g) force applications. METHODS: Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from 2 cities in Turkey with high and low fluoride concentrations in the public water of ≥ 2 and ≤ 0.05 ppm, respectively. The patients were randomly separated into 4 groups of 12 each: group 1, high fluoride intake and heavy force; group 2, low fluoride intake and heavy force; group 3, high fluoride intake and light force; and group 4, low fluoride intake and light force. Light or heavy buccal tipping orthodontic forces were applied on the maxillary first premolars for 28 days. At day 28, the teeth were extracted, and the samples were analyzed with microcomputed tomography. RESULTS: Fluoride reduced the volume of root resorption craters in all groups; however, this effect was significantly different with high force application (P = 0.015). It was also found that light forces caused less root resorption than heavy forces. There was no statistical difference in the amount of root resorption observed on root surfaces (buccal, lingual, mesial, and distal) in all groups. However, the middle third of the roots showed the least root resorption. With high fluoride intake and heavy force application, less root resorption was found in all root surfaces and root thirds. CONCLUSIONS: Fluoride may reduce the volume of root resorption craters. This effect is significant with heavy force applications (P <0.05). The cervical and apical thirds of the root showed significantly greater root resorption after the application of buccal tipping force for 4 weeks.

The effect of fluoride on orthodontic tooth movement in humans. A two- and three-dimensional evaluation.

AIMS: The aim of the present study was to determine whether high and low fluoride concentrations in drinking water affected the early stages of tooth movement when heavy and light orthodontic forces were applied for 4 weeks. A further aim was to compare and evaluate the resulting two-dimensional (2-D) and three-dimensional (3-D) orthodontic tooth movement. METHODS: The sample consisted of 96 maxillary upper first premolars from 48 patients who required premolar extractions as part of their orthodontic treatment. Patients were selected from two different cities in Turkey with low and high fluoride concentrations of 0.05 and 2 ppm, respectively. The patient sample was divided into four groups according to the magnitude of force applied to the first premolars and the concentration of fluoride in the public water supply; Group 1, High fluoride intake (> or = 2 ppm)-Heavy force (225 g); Group 2, Low fluoride intake (< or = 0.05 ppm)-Heavy force; Group 3, High fluoride intake-Light force (25 g); and Group 4, Low fluoride intake-Light force. A light or heavy buccal tipping orthodontic force was applied to the upper first premolars for 4 weeks. The first three palatal rugae were used for the superimposition of patient casts in a 2-D and 3-D evaluation of generated movements. RESULTS: It was found that heavy force application and fluoride intake increased the average rate of tooth movement. It was further shown that age was negatively correlated with tooth movement in the 2-D and 3-D measurements. CONCLUSIONS: The average rate of tooth movement was found to be greater in the heavy force and high fluoride intake group (Group 1HH). Age was negatively correlated with orthodontic tooth movement. Two- and three-dimensional methods were accurate for the assessment of tooth movement after four weeks of buccal tipping force application when the palatal rugae were used for superimposition.