Assessment of bone density in interradicular areas using fractal analysis method in individuals with different vertical growth patterns

Aim: The aim of this study is to comparatively evaluate the cortical and trabecular bone density and bone thickness in interradicular, infrazygomatic crest (IZC), and mandibular buccal shelf (MBS) regions, which are important for orthodontic miniscrew applications in individuals with different vertical growth patterns. Material and method: CBCT images of 90 individuals with Class I skeletal relationship, including hypodivergent (n=30), normodivergent (n=30), and hyperdivergent (n=30) patients who applied to Inonu University Faculty of Dentistry Department of Orthodontics, were included in the study. Cortical bone thickness, trabecular bone thickness, and total alveolar bone thickness were measured in interradicular regions, IZC, and MBS areas in maxilla and mandible. Additionally, cortical bone density was evaluated using Hounsfield Units (HU), and trabecular bone density was assessed using fractal analysis in these regions. Results: Hypodivergent individuals showed significantly higher cortical bone thickness and density compared to other groups. In the IZC region, the 16 DB area demonstrated thicker cortical bone structure compared to the 16 MB area. In the MBS region, the distal area showed higher cortical bone thickness values compared to the mesial area. All groups showed significant decrease in trabecular bone and total alveolar bone thickness from posterior to anterior regions. Hyperdivergent individuals showed lower cortical bone thickness and density compared to other groups. Conclusion: Hypodivergent individuals were identified as the most suitable patient group for miniscrew applications. Posterior regions, especially the 46-47 and 45- 46 regions in the mandible, were determined as ideal areas for miniscrew applications due to high cortical bone thickness. For hyperdivergent individuals, due to lower cortical bone thickness and density, more careful consideration and necessary precautions are recommended during miniscrew applications. Keywords: Miniscrew, Cortical bone thickness, Fractal analysis, Hounsfield unit, Cone beam computed tomography