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
Ersan Ilsay Karadeniz, Carmen Gonzales, Oyku Nebioglu-Dalci, Dennis Dwarte, Tamer Turk, Devrim Isci, Aynur M. Sahin-Saglam, Huseyin Alkis, Selma Elekdag-Turk, and M. Ali Darendeliler. Am J Orthod Dentofacial Orthop 2011;140:e199-e210
I ntroduction: 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.
How does the rate of dentoalveolar distraction affect the bone regenerate produced?
Adam C. Spencer, Phillip M. Campbell, Paul Dechow, Michael L. Ellis, and Peter H. Buschang. Am J Orthod Dentofacial Orthop 2011;140:e211-e221
I ntroduction: This experimental study was designed to evaluate how the rate of dentoalveolar distraction into a bony defect affects bone quality and quantity. Methods: Using 6 adult foxhound dogs and a randomized split-mouth design, we evaluated the differences between regenerate bone produced by distracting segments of bone containing the second premolars at either 1 or 2 mm per day for 5 days, followed by a 6-week consolidation period. Microcomputed tomography was used to evaluate bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. Results: The lingual aspect of the regenerate exhibited more bone than did the buccal aspect, and all but one of the 12 specimens showed less than 1 mm of vertical bone deficiency in the regenerate area. No differences were found between the 1-mm per day and the 2-mm per day rates for bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. With the exception of trabecular separation on the 2-mm per day side ( P = 0.030), there were no statistically significant differences between the mesial, middle, and distal segments of the regenerate. Compared with control bone, the regenerate bone was less dense, and had less bone volume, a higher trabecular number, and approximately half the trabecular thickness. Conclusions: Bone regenerate produced by rates of 1 and 2 mm per day of dentoalveolar distraction was similar in quality and quantity. Although less mature, the size and shape of the regenerate bone produced by rapid dentoalveolar distraction was comparable with the control bone.
How does the rate of dentoalveolar distraction affect the bone regenerate produced?
Adam C. Spencer, Phillip M. Campbell, Paul Dechow, Michael L. Ellis, and Peter H. Buschang. Am J Orthod Dentofacial Orthop 2011;140:e211-e221
I ntroduction: This experimental study was designed to evaluate how the rate of dentoalveolar distraction into a bony defect affects bone quality and quantity. Methods: Using 6 adult foxhound dogs and a randomized split-mouth design, we evaluated the differences between regenerate bone produced by distracting segments of bone containing the second premolars at either 1 or 2 mm per day for 5 days, followed by a 6-week consolidation period. Microcomputed tomography was used to evaluate bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. Results: The lingual aspect of the regenerate exhibited more bone than did the buccal aspect, and all but one of the 12 specimens showed less than 1 mm of vertical bone deficiency in the regenerate area. No differences were found between the 1-mm per day and the 2-mm per day rates for bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. With the exception of trabecular separation on the 2-mm per day side ( P = 0.030), there were no statistically significant differences between the mesial, middle, and distal segments of the regenerate. Compared with control bone, the regenerate bone was less dense, and had less bone volume, a higher trabecular number, and approximately half the trabecular thickness. Conclusions: Bone regenerate produced by rates of 1 and 2 mm per day of dentoalveolar distraction was similar in quality and quantity. Although less mature, the size and shape of the regenerate bone produced by rapid dentoalveolar distraction was comparable with the control bone.
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