Feifei Jiang1, Jie Chen2, Katherine Kula3, Huiying Gu4, Yansheng Du5, George Eckert5. 1. Department of Mechanical Engineering, Indiana University Purdue University, Indianapolis, Ind. 2. Department of Mechanical Engineering, Indiana University Purdue University, Indianapolis, Ind; Department of Orthodontics and Oral Facial Genetics, Indiana University, Indianapolis, Ind. Electronic address: jchen3@iupui.edu. 3. Department of Orthodontics and Oral Facial Genetics, Indiana University, Indianapolis, Ind. 4. Department of Neurology, Indiana University, Indianapolis, Ind. 5. Department of Biostatistics, Indiana University, Indianapolis, Ind.
Abstract
INTRODUCTION: The hypothesis of this study was that multiple factors are dominant in causing external apical root resorption (EARR). The objective of this investigation was to better understand the clinical factors that may lead to EARR. METHODS: Maxillary cone-beam computed tomography scans of 18 subjects who were treated with bilateral canine retractions during orthodontics were used to calculate EARR. The subjects were treated using well-calibrated segmental T-loops for delivering a 124-cN retraction force and the moment-to-force ratio suitable for moving the canine under either translation or controlled tipping. The subjects' age, sex, treatment duration, and genotype were collected. RESULTS: Six subjects of the 18 showed definite EARR, meaning that load was not the only causing factor. All 5 subjects with the genotype identified had GG genotype of IL-1β rs11143634, indicating that people with this genotype may be at high risk. Longer treatment duration, female sex, and older age may also contribute to EARR, although the findings were not statistically significant. CONCLUSIONS: EARR appears to be related to multiple factors. The orthodontic load and the genotype should be the focuses for future studies.
INTRODUCTION: The hypothesis of this study was that multiple factors are dominant in causing external apical root resorption (EARR). The objective of this investigation was to better understand the clinical factors that may lead to EARR. METHODS: Maxillary cone-beam computed tomography scans of 18 subjects who were treated with bilateral canine retractions during orthodontics were used to calculate EARR. The subjects were treated using well-calibrated segmental T-loops for delivering a 124-cN retraction force and the moment-to-force ratio suitable for moving the canine under either translation or controlled tipping. The subjects' age, sex, treatment duration, and genotype were collected. RESULTS: Six subjects of the 18 showed definite EARR, meaning that load was not the only causing factor. All 5 subjects with the genotype identified had GG genotype of IL-1β rs11143634, indicating that people with this genotype may be at high risk. Longer treatment duration, female sex, and older age may also contribute to EARR, although the findings were not statistically significant. CONCLUSIONS: EARR appears to be related to multiple factors. The orthodontic load and the genotype should be the focuses for future studies.