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Ho, Jeremy Ka Chun

University of British Columbia

Objectives: To investigate the application of virtual surgical planning (VSP) for three-dimensional (3D) hard and soft tissue assessment in orthognathic patients with a novel digital workflow. Methods: Twenty-one consecutively treated pre-surgical patients were selected from two private oral surgeon’s offices. Soft tissue scans of the face with the Artec Space Spider and intra-oral scans, were taken one month before surgery (T0), then two months (T1), and six months (T2) after orthognathic surgery. Cone beam CTs (CBCTs) were taken only at T0 and T1. Serial 3D soft tissue region and landmark changes were assessed by root mean square (RMS) after superimposing the T1 and T2 scans over T0 in Geomagic Control X software, separately. The achieved hard tissue landmark changes were assessed and compared with the VSP three-dimensionally. The correlation of hard and soft tissue changes was also tested with correlation coefficient tests. The differences in soft and hard tissue changes between the Invisalign® clear aligner and fixed appliances samples were also compared with two sample-independent t-tests. Results: The Artec Space Spider captured soft tissue images with the same accuracy as CBCT. This digital workflow was accurate, repeatable, and reproducible. From two to six months after surgery, there was clinically significant soft tissue relapse of maxillary (16-69%) and mandibular (9-36%) regions and landmarks which were highly variable and asymmetrical. Predicted virtual surgical movements were highly accurate (5-15%) for hard tissue landmarks. Ratios of soft tissue to hard tissue changes measured in three dimensions two months following surgery were similar to findings in literature measured in two dimensions. There were generally no differences in changes in soft and hard tissue landmarks or VSP for fixed versus Invisalign patients. Conclusions: The Artec Space Spider can be used as part of a novel digital workflow for VSP. Clinicians and patients should have great confidence that VSP is highly accurate and applicable for both fixed and Invisalign cases. Additionally, clinically significant soft tissue relapse can be anticipated between two to six months after surgery.

Text

2023-11-23

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86651

Craniofacial Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/