3D Analysis of Post-surgical Treatment Changes following Mandibular Advancement

OBJECTIVE: Cone-beam CTs (CBCT) were used to assess 3D skeletal transverse, antero-posterior, and vertical changes following mandibular advancement (BSSO) from 6 weeks post-surgery to the end of orthodontic treatment (~1 year post-surgery) in 21 patients.

METHODS: Dolphin3D software was used to calculate 12 3D linear and 8 3D angular measurements to describe the transverse, antero-posterior, and vertical positional changes that occurred. General linear models were used to assess the changes.

RESULTS: By the end of orthodontic treatment (~1 yr after surgery), the inter-condylar width between the medial poles had decreased (p<0.01 ) and angulation of the condylar poles relative to the midsagittal plane for both condyles had increased (p<0.001). The anterior and posterior facial heights and inter-rami width were stable (p>.0.1) but both the right and left mandibular rami/corpus angles opened (p<0.0001) suggesting that the change was related to the position of the ramus.

CONCLUSION: The condyles appear to play an important role in post-surgical adaptation to mandibular advancement surgery. However, 3D linear and angular analyses are limited in the precise localization of the surface remodeling that may underlie the observed positional changes.

Support: NIDCR DE017727 and DE005215