Mathematical Model for Buccal Cortical Bone Thickness

Objectives: To assess interradicular spaces and buccal  cortical bone thickness of the alveolar process of maxilla and mandible in subjects with class I skeletal relationship and to formulate a prediction formula for the buccal cortical bone thickness as an aid for orthodontic miniscrew placement. Methods:  The study was carried out using cone-beam computed tomography (CBCT) images of 80 skeletal class I adult subjects. Interradicular spaces and buccal cortical bone thickness were obtained at the alveolar processes from first premolar to second molar at 2 different vertical levels (6,and 8mm) from the cementoenamel junction (CEJ).  Measurements were used to formulate a mathematical model  for prediction of buccal cortical bone thickness. The model choice was based on least sum square error. The formulated model was tested on a control sample. Results: All mandibular measurements were higher than their respective maxillary measurements, except for interradicular distance between second premolar and first molar which was higher in the maxilla. Mandibular measurements increase apically and posteriorly. For both arches Interradicular distance at 6 mm from CEJ showed a high correlation with buccal cortical thickness (r > 0.85). Testing the performance of the formulated regression model in the  maxilla and mandible resulted in R² value of 0.85 and 0.89 respectively. Conclusions: A pattern could be characterized for the relationship between interradicular distance and buccal cortical bone thickness in subjects with class I skeletal relationship. The formulated model may be used to predict buccal cortical bone thickness as an aid for orthodontic miniscrew placement.  Goodness of fit  for the formulated model was higher in the mandible.