Evaluation of infrazygomatic crest thickness

Introduction: The aim of this study was to determine the thickness of the infrazygomatic crest (IZC) at the level of the mesiobuccal and distobuccal roots of the right and left upper first molars using cone beam computed tomography (CBCT) images to evaluate the relationship between age, gender, hypothetical miniscrew insertion angle, vertical face dimension, maxillary sinus volume and root tip-maxillary sinus floor distance. Methods: 149 CBCT images taken for diagnosis and treatment from the archive of Hacettepe University Faculty of Dentistry Department of Orthodontics were included in this study. Individuals with a mean age of 20.7 ± 6.9 years; they were grouped according to age (64 individuals ≤18 years, 85 individuals ≥19 years), gender (79 women, 70 men) and vertical facial dimensions (41 individuals brachyfacial, 69 individuals mesofacial, 39 individuals doligofacial). Using Dolphin 3D (Dolphin Imaging & Management Solutions, Chatsworth, California, USA) software; GoGnSN angles, IZC thicknesses and root tip-maxillary sinus floor distances at different hypothetical miniscrew entry angles (50⁰, 60⁰, 70⁰) for mesiobuccal and distobuccal roots of maxillary right and left first molars, and right and left maxillary sinus volumes were measured. Results: It was determined that the mean IZC thickness increased as the hypothetical miniscrew insertion angle increased. The mean IZC thickness in individuals aged 18 years and younger was found to be higher than in individuals aged 19 and over. There was a weak and moderate negative correlation between IZC thickness and maxillary sinus volume values and a weak positive correlation between IZC thickness and root tip-maxillary sinus floor distance values. Conclusions: This study showed that IZC thickness was related to individual parameters that should be carefully evaluated prior to IZC miniscrew planning in orthodontic treatment. It was observed that IZC thickness was highly correlated with age and miniscrew insertion angle. Our study suggests that CBCT is a suitable method for determining the localization of miniscrew insertion. Key words: Infrazygomatic Crest, Cone Beam Computed Tomography, Maxillary Sinus