In order to compare the premaxilla and symphysis in Class I and Class III individuals, we measured the following parameters on CBCT scans: incisor inclination, symphyseal morphology, upper alveolar process morphology, symphyseal and maxillary leeway space, as well as anterior and posterior maxillary and mandibular bone thickness at various points below the cementoenamel junction.

CBCT scans were taken of 62 individuals (41 females and 21 males) of ages ranging between 11 and 53years (mean 23.26). The dentoskeletal relationship and alveolar process morphology (thickness) were evaluated on axial slices of the upper and lower jaws, and Student's parametric t-test for paired data was used to compare Class I and Class III values within different facial types.

Many significant differences in measurements between the two facial types were noted in terms of tooth inclination, alveolar thickness, and leeway space.

Our findings confirm that Class III patients have little periodontal support at the upper and lower incisors, irrespective of the amount of symphyseal leeway space available, and any tooth movement must therefore be carefully planned and monitored.