Buccal Bone Density for Mini-implant Sites is Greater in Females

Objectives: Success of mini implants for orthodontic purposes is dependent on both the quantity and quality of the bone. The objectives of this study were to compare buccal bone thickness and density in three different vertical facial types in the maxilla and mandible along with variation between age and gender to determine the quality of bone evaluated using Cone Beam CT (CBCT).
Methods: CBCT scans of 291 patients seeking orthodontic treatment were retrospectively analyzed for this study. CBCT-generated lateral cephalograms were used to make linear and angular measurements to classify each patient as hypodivergent, normodivergent, or hyperdivergent. Within each facial type, patients were further divided by gender and age (growing and non-growing). Reconstructed cross sectional images in both the maxilla and mandible between first molar and second premolar were chosen for evaluation. These sites were chosen as they are the preferred locations for placing mini implants. At each location, the buccal bone thickness and density were measured.
Results: Simple descriptive statistics were used to summarize the outcomes. Buccal bone width in the maxilla for the hypodivergent group was 1.39mm and density was 913.1PIVs. In the mandible the buccal bone width was 2.05mm and the density was 1304.1PIVs. For the hyperdivergent group, buccal bone width in the maxilla was 1.32mm and the density was 907.8PIVs. In the mandible the average width was 1.73mm and the density was 1227.0PIVs. Buccal bone width in the normal group in the maxilla was 1.37mm and density was 855.3PIVs. In the mandible it was 1.79mm and density was 1192.2PIVs. Bone density at these sites was more in females compared to males in all groups.
Conclusions: Overall, the hypodivergent group showed greater buccal bone width and density. In adult patients, males have greater buccal bone width. Females have higher density in both growing and adult groups.