Cortical Bone Thickness and Interradicular Distance in Different Skeletal Relationship

Objectives: To assess buccal cortical bone thickness and interradicular distance in the maxilla and mandible in subjects with different skeletal relationship as an aid in orthodontic miniscrew placement.
Methods: The study was carried out using Cone Beam CT (CBCT) images of 180 adult subjects with skeletal class I, II and III relationship. Buccal cortical bone thickness and interradicular spaces were obtained from first premolar to second molar at 2 different vertical levels (6 and 8mm) from the cementoenamel junction (CEJ). Analysis of variance (ANOVA) was used to analyse differences in cortical bone thickness and interradicular distance
Results: In the maxilla the highest interradicular space existed between second premolar and first molar for all skeletal classes, while cortical bone thickness was highest between first and second molar in Class I and between first and second premolar in Class II and Class III. In the mandible the highest interradicular space existed between first and second molar in Class I subjects and between first and second premolar in Class II and Class III subjects. Buccal cortical plate was thickest between first and second molar in all skeletal classes. Interradicular measurements between first and second premolar in both arches were significantly higher in class II subjects (P < 0.05). Cortical bone thickness between first and second molar in class I subjects was significantly higher than class II subjects in both arches (P < 0.05). Root distance increase apically in both arches, While cortical thickness increase apically only in mandible.
Conclusions: Buccal cortical bone thickness and interradicular spaces could be influenced by skeletal relationship. The site with highest mean for both buccal cortical thickness and root distance at both vertical levels was between mandibular first and second molar in Class I subjects. Skeletal relationship need to be considered in site choice for orthodontic miniscrew placement.