Three-dimensional regional displacements after mandibular advancement surgery: one year of follow-up.
OBJECTIVE
To evaluate the association of 3-dimensional changes in the position of the condyles, rami, and chin at splint removal and 1 year after mandibular advancement surgery.


METHODS
This prospective observational study used preoperative and postoperative scans of 27 subjects presenting with a skeletal Class II jaw relationship with a normal or deep overbite. An automatic technique of cranial base superimposition was used to assess the positional and/or remodeling changes in the anatomic regions of interest. The displacements were visually displayed and quantified using 3-dimensional color maps. The positive and negative values of surface distances in the color maps indicated the direction of the displacements. Pearson correlation coefficients and a linear model for correlated data were used to evaluate the association between the regional displacements.


RESULTS
The postoperative adaptations in the chin position between splint removal and 1 year after surgery were significantly negatively correlated with changes in the borders of the posterior ramus (left, r = -0.73, P ≤ .0001; and right, r = -0.68, P = .00) and the condyles (left, r = -0.53, P = .01; and right, r = -0.46, P = .02), indicating that these structures tended to be displaced in the same direction. Even though the mean condylar displacement with surgery was less than 1 mm, individual displacements greater than 2 mm with surgery were observed for 24% of the condyles. The condylar displacements were maintained at 1 year after surgery for 17% of the condyles.


CONCLUSIONS
The surface distance displacements indicated that the postoperative adaptations at different anatomic regions were significantly related.
Department of Orthodontics, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil.
Alexandre T
AT
Motta
Lucia H S
LH
Cevidanes
Felipe A R
FA
Carvalho
Marco A O
MA
Almeida
Ceib
C
Phillips
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000033:anatomy & histology / Q000601:surgery; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003768:Dental Occlusion, Centric; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery; D008334:Mandible / Q000033:anatomy & histology*; D019186:Mandibular Advancement / Q000295:instrumentation / Q000379:methods*; D008335:Mandibular Condyle / Q000033:anatomy & histology; D010027:Osteotomy / Q000379:methods; D011446:Prospective Studies; D019291:Skull Base / Q000033:anatomy & histology; D013165:Splints
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