American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics | 2021
Safe sites for orthodontic miniscrew insertion in the infrazygomatic crest area in different facial types: A tomographic study.
Abstract
INTRODUCTION\nTemporary skeletal anchorage devices (TSADs) are used to obtain skeletal anchorage for orthodontic treatment. Their insertion in the infrazygomatic crest (IZC) allows efficient orthodontic mechanics. Different facial types have different bone configurations. We aimed to evaluate the differences in bone thicknesses in the IZC area among patients of each facial type to determine a safe zone for TSAD insertion.\n\n\nMETHODS\nFor this retrospective study, 86 cone-beam computed tomography (CBCT) scans were divided into 3 groups according to the facial type: group I, 24 CBCT scans of hyperdivergent patients; group II, 30 scans of neutral patients; and group III, 32 scans of hypodivergent patients. The buccal alveolar bone thickness was measured in 6 zones between the second premolar and distal root of the second\xa0molar, 5, 7, 9, and 11\xa0mm apical to the alveolar crest.\n\n\nRESULTS\nThe IZC areas with minimum thickness for TSAD insertion follows: group I, between first and second\xa0molars at 11\xa0mm from the alveolar crest, mesial root of the second\xa0molar at 9\xa0mm from the crest, and distal root of the second\xa0molar at 11\xa0mm from the crest; groups II and III, between first and second\xa0molars at 11\xa0mm from the crest and mesial root of the second\xa0molar at 11\xa0mm from the crest.\n\n\nCONCLUSIONS\nThe safe zones for IZC miniscrew insertion are located 11\xa0mm from the alveolar crest between the maxillary first and second\xa0molars and on the mesial root of the second\xa0molar for all the 3 facial types.