Computed tomography assessment of maxillary bone density for orthodontic mini-implant placement with respect to vertical growth patterns

Abstract

Objective: To quantitatively measure and report bone density of maxilla in the interradicular (alveolar and basal bone) and infrazygomatic crest (IZC) region in various growth patterns among Dravidian individuals. Design: This was a retrospective spiral computed tomography (CT) study. Setting: The study was conducted at the Department of Orthodontics, Saveetha Dental College and Hospital, Tamil Nadu, India. Methods: Sixty CT scans (24 men, 36 women; mean age = 25.3 years and 23.8 years, respectively) divided equally into three groups based on vertical facial proportions were included. Bone density measurements in Hounsfield units (HU) were performed using Philips and RadiAnt DICOM viewers. Buccal cortical, palatal cortical and cancellous bone regions were analysed in a Philips DICOM viewer and IZC region was analysed in a RadiAnt DICOM viewer. Statistical analysis with one-way ANOVA and post-hoc Tukey HSD test was done. Results: The hypodivergent group had a significantly higher bone density at the buccal cortex in posterior region ( P < 0.05) when compared to the normodivergent and hyperdivergent groups. Buccal basal bone was denser than buccal alveolar bone ( P < 0.05) in all three groups. In the IZC region, hypodivergent groups had significantly higher density values when compared to the normodivergent and hyperdivergent groups ( P < 0.05). Conclusion: The present study concluded that cancellous bone density in the interradicular regions was greatest in the anterior sites and was not influenced by growth pattern. Hypodivergent groups tend to have higher density in the posterior regions (buccal and palatal cortical bone) and at the IZC region compared to normodivergent and hyperdivergent groups.