Frontal Changes in the Lower Face After Clockwise Rotation of the Maxillomandibular Complex Without Perisurgical Orthodontic Treatment in Angle Class I and Skeletal Class III Women.
BACKGROUND
Orthognathic surgery has become more popular to slenderize a wide lower face and to improve facial esthetics in Asian patients with normal occlusion. Clockwise rotation (CR) of the maxillomandibular complex (MMC) steepens the mandibular plane. This study performed a quantitative analysis on the influence of CR on slenderness of the lower face from the frontal view.


METHODS
This retrospective study included 36 female patients with Angle Class I occlusion and skeletal Class III pattern. The subjects underwent CR of the MMC without perioperative orthodontic treatment and change in the occlusion only for the purpose of esthetic improvement. Linear and angular variables were measured on a cephalogram and three-dimensional computed tomography (3D CT) obtained before and at least 6 months after surgery. Data were analyzed using paired t tests and Spearman correlations. Univariate regression analysis was used to predict the postoperative change according to the amount of posterior impaction.


RESULTS
The mean posterior impaction was 3.81 mm. All mandibular plane angle (MPA) measurements were increased (ranged from 5.69° to 13.12°, p < 0.001), exhibiting a significant correlation with the amount of posterior impaction. Bigonial width measurements were decreased after surgery (ranged from 4.97 to 5.51 mm, p < 0.001). Among the MPAs derived from the 3D CT, the coronal projection from the frontal view exhibited a discrepancy between right and left side.


CONCLUSIONS
The changes in linear and angular measurements in this study indicate that the lower face becomes narrower and more slender as the MMC rotates in a clockwise direction. Orthognathic surgery with CR has the advantage of increasing the MPAs and obtaining natural soft tissue contouring while minimizing the amount of bone resection.


METHODS
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DA Plastic Surgery Clinic, 8F, W Tower, 54, Seocho-daero 77-gil, Seocho-gu, Seoul, Republic of Korea.
Sang Woo
SW
Lee
Banobagi Plastic Surgery Clinic, Seoul, Republic of Korea.
Jeongmok
J
Cho
DA Plastic Surgery Clinic, 8F, W Tower, 54, Seocho-daero 77-gil, Seocho-gu, Seoul, Republic of Korea.
Kikap
K
Kim
DA Plastic Surgery Clinic, 8F, W Tower, 54, Seocho-daero 77-gil, Seocho-gu, Seoul, Republic of Korea. ashbin@naver.com.
Seung Hyun
SH
Ahn
D000328:Adult; D000704:Analysis of Variance; D002508:Cephalometry / Q000379:methods; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008313:Malocclusion, Angle Class III / Q000000981:diagnostic imaging* / Q000601:surgery*; D063168:Mandibular Osteotomy / Q000379:methods; D063166:Maxillary Osteotomy / Q000379:methods; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D020127:Recovery of Function; D012189:Retrospective Studies; D012399:Rotation; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
Computed tomography; Mandible; Occlusal plane; Orthognathic surgery