Cephalometric effects of combined palatal expansion and facemask therapy on Class III malocclusion.
The purpose of this study was to examine the cephalometric changes that occur with palatal expansion/facemask therapy for Class III malocclusion. Pretreatment and posttreatment lateral cephalograms from 21 patients were traced and analyzed by traditional cephalometric measures, an x-y coordinate system, and along the functional occlusal plane. Differences between T1 and T2 values were analyzed with paired t-tests. Mean ages were 7.26 years (T1) and 8.18 years (T2). Average treatment time was 11.05 months. Statistically significant anterior movement of the maxilla occurred with increases in SNA (+2.35), maxillary depth (+2.22), and ANB (+3.66), and anterior movement of A-point (+3.34 mm) and ANS (+3.17 mm). The maxilla rotated counterclockwise, with PNS moving down more than ANS (-2.21 mm and -0.82, respectively). The mandible rotated clockwise with mild decreases in SNB (-1.32) and facial depth, (-1.2) but significant downward movement at menton (-4.34 mm). Occlusal plane analysis demonstrated that the correction was due more to the maxilla than the mandible (+2.35 and -1.88 mm, respectively). The maxillary molars moved forward (+1.70 mm) as did the incisors (+1.75 mm). Soft tissue changes included the nose and upper lip moving forward (3.43 and 3.67 mm, respectively), and menton moving downward (-3.49 mm). The results indicate that facemask/palatal expansion therapy improves Class III malocclusion by a combination of skeletal and dental changes that occur the anteroposterior dimension and in the vertical plane of space.
Nartallo-Turley
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PE
University of California, School of Dentistry, Section of Orthodontics, Los Angeles 90024-1668, USA.
Turley
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PK
D000704:Analysis of Variance; D002508:Cephalometry; D002648:Child; D002675:Child, Preschool; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D008313:Malocclusion, Angle Class III / Q000628:therapy*; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D010155:Palatal Expansion Technique; D014716:Vertical Dimension