Comparison of progressive cephalometric changes and postsurgical stability of skeletal Class III correction with and without presurgical orthodontic treatment.
OBJECTIVE
This study compares 1) progressive dental and skeletal changes, 2) postsurgical stability, and 3) treatment efficacy of patients with skeletal Class III correction with and without presurgical orthodontic treatment.


METHODS
The study includes 53 patients who underwent orthognathic surgery (OGS) to correct skeletal Class III malocclusion. The patient grouping is based on presurgical orthodontics: surgical-first (SF) approach (n = 18) and modified-conventional (MC) approach (n = 35). This study divides the MC group into 2 groups based on whether patients underwent tooth extraction in the presurgical phase (Ext group) (n = 10) or not (Nxt group) (n = 25). Serial lateral cephalometric film measurements identify skeletal and dental changes before treatment (T1), before OGS (T2), 1 month after OGS (T3), and at completion of treatment (T4). This investigation reviews the medical charts for treatment progress and duration.


RESULTS
In the presurgical phase, the Ext group showed mild retraction of the upper incisors and more proclination of the lower incisors than the Nxt group. The skeletal sagittal parameters were similar from T1 to T4 in both the SF and MC groups. In the SF group, SN/U1 decreased 6.2° after surgery and was mildly proclined at T4; in the MC group, upper incisor inclination (SN/U1) increased 1.8° from T1 to T4, being 9.4° greater than that in the SF group at T4. The lower incisor inclination (MP/L1) was similar at T4 in both groups. In the MC group, the MP/L1 was shown to be proclined 4.5° before surgery, retroclined 1.9° after surgery, and further retroclined 4.5° until T4. The relapse rate of the mandibular setback was 14.3% in the SF group and 15.7% in the MC group without significant differences. The percentage of sagittal relapse less than 2 mm was 50% in the SF group and 54% in the MC group. The ratio was greater in the MC group with a relapse between 2 and 4 mm but lesser with a relapse greater than 4 mm. The Ext group showed a 3-month longer treatment duration than the Nxt group.


CONCLUSIONS
The amount of skeletal correction and postsurgical relapse, as well as treatment duration, were no different in Class III OGS patients with or without presurgical orthodontic treatment. The presurgical work of lower incisor proclination returned to an inclination similar to the initial status after completing treatment. The final outcome of patients evidenced no difference in lower incisor inclination, with or without presurgical orthodontics.
Graduate Institute of Craniofacial and Oral Science, Chang Gung University, Taipei, Taiwan.
Ellen Wen-Ching
EW
Ko
Sam Sheng-Pin
SS
Hsu
Hsin-Yi
HY
Hsieh
Yu-Chih
YC
Wang
Chiung Shing
CS
Huang
Yu Ray
YR
Chen
D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery* / Q000628:therapy; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008437:Maxilla / Q000473:pathology / Q000601:surgery; D009295:Nasal Bone / Q000473:pathology; D009971:Orthodontics, Corrective; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D010027:Osteotomy / Q000379:methods; D019340:Osteotomy, Le Fort / Q000379:methods; D010347:Patient Care Planning; D011300:Preoperative Care; D012008:Recurrence; D012189:Retrospective Studies; D012658:Sella Turcica / Q000473:pathology; D013997:Time Factors; D014081:Tooth Extraction; D014087:Tooth Movement Techniques; D016896:Treatment Outcome; D055815:Young Adult