Comparison of maxillary basal arch forms using the root apex in adult women with different skeletal patterns: A pilot study.

Introduction: This study aimed to establish maxillary basal arch forms using the root apices and to determine the differences in the basal arch forms in adult women with different sagittal skeletal patterns.

Methods: This retrospective study included 91 adult women, with either a Class I (n = 24), Class II Division 1 (n = 22), Class II Division 2 (n = 23), or Class III (n = 22) malocclusion, who underwent cone-beam computed tomography. Three-dimensional coordinates of the root apices were determined using the multiplanar reformation mode of OnDemand3D software (Cybermed Inc, Seoul, South Korea). Two-dimensional coordinates were converted from acquired 3-dimensional coordinates via projection on the palatal plane, and the Procrustes superimposition method was used to build the basal arch form. Finally, interroot width measurements were performed for basal arch form comparisons.

Results: There were significant differences among the 4 groups (P <0.05) with respect to the intercanine width. The intercanine width of Class II Division 1 group was significantly narrower than that of the other groups. The Class II Division 1 and Class II Division 2 groups tended to have tapered arch forms and squared arch forms, respectively.

Conclusions: We established maxillary basal arch forms using the root apices. The Class II Division 1 group had a significantly narrower intercanine distance. The use of the root apex to depict the basal arch form seems reasonable.