Orthodontic Research Today is a free monthly online journal that collates and summarizes the latest research about Orthodontic, including details on braces, retainers, treatment.

Computed tomographic analysis of tooth-bearing alveolar bone for orthodontic miniscrew placement.

Lee KJ, Joo E, Kim KD, Lee JS, Park YC, Yu HS

Department of Orthodontics, Oral Science Research Center, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.

INTRODUCTION: When monocortical orthodontic miniscrews are placed in interdental alveolar bone, the safe position of the miniscrew tip should be ensured. This study was designed to quantify the periradicular space in the tooth-bearing area to provide practical guidelines for miniscrew placement. METHODS: Computerized tomographs of 30 maxillae and mandibles were taken from nonorthodontic adults with normal occlusion. Both mesiodistal interradicular distance and bone thickness over the narrowest interradicular space (safety depth) were measured at 2, 4, 6, and 8 mm from the cementoenamel junction. RESULTS: Mesiodistal space greater than 3 mm was available at the 8-mm level in the maxillary anterior region, between the premolars, and between the second premolar and the first molar at 4 mm. In the mandible, sufficient mesiodistal space was found between the premolars, between the molars, and between the second premolar and the first molar at the 4-mm level. Safety depth greater than 4 mm was found in the maxillary and mandibular intermolar regions, and between the second premolar and the first molar in both arches. CONCLUSIONS: Subapical placement is advocated in the anterior segment. Premolar areas appear reliable in both arches. Angulated placement in the intermolar area is suggested to use the sufficient safety depth in this area.

Published 13 April 2009 in Am J Orthod Dentofacial Orthop, 135(4): 486-94.
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