The purpose of this study was to evaluate palatal contours in nonextraction orthodontic treatment and long-term stability in patients with Class II Division 1 malocclusions.
Data were obtained from maxillary study models before treatment, after treatment, and at least 5 years postretention. Data were collected with a digital pantograph in the canine, second premolar, and first molar regions. Palatal width, base width, palatal height, and alveolar angle were evaluated.
During treatment, the canine region was stable; in the premolar and molar regions, there were statistically significant increases in transverse (palatal and base widths) and palatal height measurements, whereas the alveolar angle decreased. In the postretention evaluation, the canine region showed the greatest modifications, except for alveolar angulation, which was stable. The premolar region showed stability, but, in the molar region, palatal width and alveolar angulation decreased.
In analyzing alterations in the geometry of palatal configuration, we concluded that a favorable transverse gain of the palatal base, from growth or orthodontics, was important for stability. The transverse gain of palatal base width during Class II treatment is important to compensate for the expected transverse loss in the cervical region and the decrease of alveolar angle in the long term.
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