J Korean Dent Sci.  2020 Jun;13(1):11-20. 10.5856/JKDS.2020.13.1.11.

Chin Profile Changes in Skeletal Class III Following Bimaxillary Surgery with or without Advancement Genioplasty

• Kim YA
• Jung HD
• Cha JY
• Choi SH

• KMID: 2503825
• DOI: http://doi.org/10.5856/JKDS.2020.13.1.11

Abstract

Purpose
This study sought to identify differences in hard and soft tissue chin profile changes in skeletal Class III patients after bimaxillary surgery, with or without advancement genioplasty.
Materials and Methods
The retrospective study was conducted based on cephalometric analysis of skeletal and soft tissue variables. Lateral cephalograms taken at 3 different time points were utilized: pre-operation (T0), immediately post-operation (T1), and at least 6 months (11.0±2.6 months) post-operation (T2). The 2 groups were matched for sample size (n=20 each). Data were analyzed using independent t-tests with Bonferroni correction. Result: Group N (bimaxillary surgery alone) and Group G (bimaxillary surgery with an advancement genioplasty by horizontal sliding osteotomy) did not differ significantly in terms of demographic characteristics. The soft tissue chin thickness of Group G increased more after surgery, followed by a greater decrease during the postoperative period, and was eventually not significantly different from Group N at T2. On the other hand, the mentolabial sulcus depth of Group G (5.5±1.3 mm) was significantly greater than that of Group N (4.4±0.9 mm) (P=0.006) at T2.
Conclusion
Although Group G showed a statistically significantly greater decrease in soft tissue chin thickness during the postoperative period, there were no significant intergroup differences in the chin profile for at least 6 months after the surgery, except for the mentolabial sulcus depth, which was greater in Group G than in Group N.

Keyword

Chin; Genioplasty; Orthognathic surgery; Prognathism; Skeletal Class III