Three-dimensional zygomatic changes after rapid maxillary expansion in growing patients

Purpose To assess the effects of rapid maxillary expansion (RME) treatment on the zygomatic bone complex (ZBC). Methods In this single-center retrospective study, pre- and posttreatment cone-beam computed tomography (CBCT) images of 38 patients treated with RME were analyzed to investigate changes in the coordinates of the ZBC landmarks. At the start of treatment (T0), the patients' mean age was 11.1 +/- 3.8 years (range 8.3-14.9 years). Cohen's d test was used to evaluate statistical differences. Results There were statistically significant differences between T0 and T1 (P < 0.01) in the measurement values for the maxillary transverse width (Delta T: 3.18 +/- 2.58, d: 1.23), frontozygomatic sutures (Delta T: 1.09 +/- 0.56, d: 0.43), lowest point of the zygomaticomaxillary sutures (Delta T: 3.16 +/- 1.78, d: 0.78), frontomaxillary angular parameter (right side Delta T: 2.81 +/- 1.63, d: 1.73; left side Delta T: 2.52 +/- 1.20, d: 2.10), frontozygomatic angular parameter (right side Delta T: 2.81 +/- 1.63 d: 1.07; left side Delta T: 2.21 +/- 2.79, d: 0.61), anterior intermaxillary distance (Delta T: 2.11 +/- 1.42, d: 0.99), interzygomaticotemporal distance (Delta T: 2.00 +/- 2.42, d: 0.99), and zygomatic angular parameter (right side Delta T: 2.06 +/- 1.29, d: 1.6; left side Delta T: 2.02 +/- 1.86, d: 1.09). Conclusions After RME in growing patients, the zygomatic bone showed pyramidal expansion in the coronal plane and parallel palatal expansion in the axial plane. In addition, significant lateral relocation of the zygomatic bone occurred. The zygomatic bone tended to rotate outward in conjunction with the maxilla, with a typical center of rotation close to the superior side of the frontozygomatic suture. These results shed light on the patterns of skeletal expansion in the zygomatic bone associated with RME in growing patients.

Automated summary

This study investigated the effects of rapid maxillary expansion (RME) treatment on the zygomatic bone complex (ZBC) through a retrospective analysis of cone-beam computed tomography (CBCT) images. The results showed that RME led to pyramidal expansion of the zygomatic bone in the coronal plane and parallel palatal expansion in the axial plane. Additionally, significant lateral relocation of the zygomatic bone was observed. These findings provide valuable insights into the patterns of skeletal expansion in the zygomatic bone associated with RME treatment.