Lei Yang1, Feifei Li2, Meng Cao2, Hong Chen3, Xi Wang3, Xuepeng Chen4, Le Yang3, Weiran Gao5, Joseph F Petrone6, Yin Ding7. 1. Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China; 264th Hospital of Chinese People's Liberation Army, Taiyuan, Shanxi, China. 2. Associate professor, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China. 3. Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China. 4. Associate professor, Department of Orthodontics, Hospital of Stomatology, Zhejiang University, Hangzhou, Zhejiang, China. 5. Attending doctor, 264th Hospital of Chinese People's Liberation Army, Taiyuan, Shanxi, China. 6. Chair, Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pa. 7. Professor and head, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China. Electronic address: dingyin@fmmu.edu.cn.
Abstract
INTRODUCTION: The purpose of this study was to propose a protocol for safe bicortical placement of mini-implants by measuring the interradicular spaces of the maxillary teeth and the bone quality. METHODS: Cone-beam computed tomography data were obtained from 50 adults. Three-dimensional reconstructions and measurements were made with SimplantPro software (Materialise, Leuven, Belgium). For each interradicular site, the bone thicknesses and interradicular distances at the planes 1.5, 3, 6, and 9 mm above the cementoenamel junction were measured. Standard bone units were defined to evaluate the influences of bone density and the different placement patterns on the stability of the mini-implants. RESULTS: The safe interradicular sites in the maxilla for bicortical placement of 1.5-mm-diameter mini-implants were in all planes between the first and second premolars, and between the second premolar and the first molar. The safe palatal sites were between the first and second molars, and the safe labial sites of the 9-mm plane were between the central incisors, and between the lateral incisor and the canine. The safe buccal sites of the 6- and 9-mm planes were between the first and second molars, and the safe buccal sites of the 3-, 6-, and 9-mm planes were between the canine and the first premolar. Most bone thicknesses were from 8 to 12 mm. The optimal placement angle between the second premolar and the first molar was 58°. Bicortical placement could have more standard bone units than unicortical placement in the maxilla. CONCLUSIONS: Bicortical placement would be more stable in the maxilla. For the site between the molars, special care should be taken at a plane higher than 6 mm to prevent maxillary sinus penetration. The most favorable interradicular area in the maxilla was between the second premolar and the first molar.
INTRODUCTION: The purpose of this study was to propose a protocol for safe bicortical placement of mini-implants by measuring the interradicular spaces of the maxillary teeth and the bone quality. METHODS: Cone-beam computed tomography data were obtained from 50 adults. Three-dimensional reconstructions and measurements were made with SimplantPro software (Materialise, Leuven, Belgium). For each interradicular site, the bone thicknesses and interradicular distances at the planes 1.5, 3, 6, and 9 mm above the cementoenamel junction were measured. Standard bone units were defined to evaluate the influences of bone density and the different placement patterns on the stability of the mini-implants. RESULTS: The safe interradicular sites in the maxilla for bicortical placement of 1.5-mm-diameter mini-implants were in all planes between the first and second premolars, and between the second premolar and the first molar. The safe palatal sites were between the first and second molars, and the safe labial sites of the 9-mm plane were between the central incisors, and between the lateral incisor and the canine. The safe buccal sites of the 6- and 9-mm planes were between the first and second molars, and the safe buccal sites of the 3-, 6-, and 9-mm planes were between the canine and the first premolar. Most bone thicknesses were from 8 to 12 mm. The optimal placement angle between the second premolar and the first molar was 58°. Bicortical placement could have more standard bone units than unicortical placement in the maxilla. CONCLUSIONS: Bicortical placement would be more stable in the maxilla. For the site between the molars, special care should be taken at a plane higher than 6 mm to prevent maxillary sinus penetration. The most favorable interradicular area in the maxilla was between the second premolar and the first molar.
Authors: Henrique M Villela; Mario Vedovello Filho; Heloísa C Valdrighi; Milton Santamaria-Jr; Carolina Carmo de Menezes; Silvia A S Vedovello Journal: Dental Press J Orthod Date: 2018-01