Stability of extraoral vertical ramus osteotomy: plate fixation versus maxillomandibular/skeletal suspension wire fixation.
The objective of this cephalometric study was to evaluate skeletal stability and time course of postoperative changes in 2 groups of mandibular prognathism patients following extraoral oblique vertical ramus osteotomy (VRO). One group (n = 22) received maxillomandibular fixation and skeletal suspension wires (MMF group) for a period of 8 weeks. In the other group (n = 22), the segments were rigidly fixed with plates and the patients were allowed to function immediately after surgery. Lateral cephalograms were taken on 5 occasions: immediately presurgical, immediately postsurgical, 8 weeks postsurgical, 6 months postsurgical, and 1 year postsurgical. During the first 8 weeks after surgery, the MMF group demonstrated posterior movement of the mandible, with an increase in mandibular plane angle, shortening of the rami, and dental compensations. Upon release of MMF and skeletal suspension wiring, a small anterior relapse tendency was observed, but the net setback 1 year after surgery was still greater than the actual surgical setback. In the plate fixation group, postoperative changes were mainly in the form of a small anterior relapse tendency in the range of 10% of the surgical setback. The results indicate that the use of plate fixation with VRO, while eliminating the inconvenience for the patient of several weeks of MMF and preventing the early side effects observed in the MMF group, also resulted in a more predictable surgical procedure, with excellent stability 1 year after surgery.
Mobarak
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KA
Karim A. Mobarak, Department of Orthodontics, Institute of Clinical Dentistry, University of Oslo, P.O. Box 1109 Blindern, 0317 Oslo, Norway. kmobarak@bigfoot.com
Krogstad
O
O
Espeland
L
L
Lyberg
T
T
D000328:Adult; D001860:Bone Plates; D002508:Cephalometry; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D007103:Immobilization; D007180:Incisor / Q000502:physiology; D019248:Jaw Fixation Techniques / Q000295:instrumentation; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008334:Mandible / Q000002:abnormalities / Q000502:physiology / Q000601:surgery*; D019647:Oral Surgical Procedures / Q000379:methods*; D011378:Prognathism / Q000601:surgery; D012189:Retrospective Studies; D055502:Secondary Prevention; D013997:Time Factors; D016896:Treatment Outcome