Related Experiment Video
Updated: Aug 12, 2026
Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition
Published on: February 23, 2024
Soft-tissue thickness changes following bimaxillary surgery in skeletal class II malocclusion
Hao Chen1,2, Dirk-Melle Beek3, Frank Baan4
1Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangzhou Medical University, Huangsha Avenue 39, Liwan District, Guangzhou, Guangdong, 510150, China.
Objectives:
This retrospective cohort study evaluated regional facial soft-tissue thickness changes after bimaxillary surgery in skeletal Class Ⅱ patients and assessed their associations with skeletal movement and patient-related factors.
Materials And Methods:
Class Ⅱ patients treated with bimaxillary advancement surgery without genioplasty were included. Postoperative CBCT scans, acquired 16.7 ± 5.3 months after surgery, were registered to the corresponding preoperative scans using voxel-based superimposition. Skeletal displacement and corresponding overlying soft-tissue thickness were assessed at subspinale (A), supradentale (Sd), infradentale (Id), supramentale (B), pogonion (Pog), and menton (Me). Soft-tissue thickness was defined as the linear distance between each hard-tissue landmark and its corresponding soft-tissue landmark. Skeletal displacement was measured at the corresponding hard-tissue landmarks.
Results:
89 patients were enrolled, 33 male and 56 female, mean age of 30.3 ± 10.3 years. Significant postoperative soft-tissue thinning was observed at A (0.40 ± 1.51 mm), Id (2.20 ± 2.11 mm), B (0.33 ± 1.30 mm), and Pog (0.48 ± 1.29 mm), whereas soft-tissue thickness at Sd and Me did not change significantly. Pearson correlation analysis indicated that thickness changes were not associated with age, sex, or CBCT interval. Larger sagittal advancement at A and Id was associated with more pronounced thinning of the corresponding soft tissue (A: r = -0.650, p < 0.001; Id: r = -0.338, p = 0.001), with ratios of thinning to movement of 0.20 and 0.30, respectively. In contrast, larger downward vertical movement of B was associated with less thinning at B (r = 0.240, p = 0.023), with a ratio of thinning to downward movement of 0.05.
Conclusion:
Bimaxillary surgery in skeletal Class II patients without genioplasty resulted in region specific soft-tissue thinning, particularly affecting the lower lip.
Clinical Relevance:
Postoperative soft-tissue thinning should be considered during surgical planning and patient communication.
