Abstract
ObjectiveTo assess the dentoskeletal changes observed in treatment of Class II, division 1 malocclusion patients with mandibular retrognathism. Treatment was performed with the Herbst orthopedic appliance during 13 months (phase I) and pre-adjusted orthodontic fixed appliance (phase II). MethodsLateral cephalograms of 17 adolescents were taken in phase I onset (T1) and completion (T2); in the first thirteen months of phase II (T3) and in phase II completion (T4). Differences among the cephalometric variables were statistically analyzed (Bonferroni variance and multiple comparisons). ResultsFrom T1 to T4, 42% of overall maxillary growth was observed between T1 and T2 (P < 0.01), 40.3% between T2 and T3 (P < 0.05) and 17.7% between T3 and T4 (n.s.). As for overall mandibular movement, 48.2% was observed between T1 and T2 (P < 0.001) and 51.8% between T2 and T4 (P < 0.01) of which 15.1% was observed between T2 and T3 (n.s.) and 36.7% between T3 and T4 (P < 0.01). Class II molar relationship and overjet were properly corrected. The occlusal plane which rotated clockwise between T1 and T2, returned to its initial position between T2 and T3 remaining stable until T4. The mandibular plane inclination did not change at any time during treatment. ConclusionMandibular growth was significantly greater in comparison to maxillary, allowing sagittal maxillomandibular adjustment. The dentoalveolar changes (upper molar) that overcorrected the malocclusion in phase I, partially recurred in phase II, but did not hinder correction of the malocclusion. Facial type was preserved.
Highlights
MethodsThe sample comprised 17 Brazilian adolescent patients (12 men and 5 women), with mean age of 12 years and 4 months ± 1 year and 2 months, and bone age corresponding to the growth spurt, as revealed by a hand-wrist radiograph
The patients were selected according to the following inclusion criteria: individuals with mandibular retrognathism and Angle Class II, division 1 malocclusion greater than half-cusp (> 3 mm); individuals with overjet > 5 mm; with model discrepancy under 4 mm; with clinical recommendation for mandibular advancement to be performed with functional orthopedic appliance
All patients that comprised this study presented, in T1, typical characteristics of Class II division 1 malocclusion, as confirmed by the initial cephalometric variables that describe the molar relationship and the overjet
Summary
The sample comprised 17 Brazilian adolescent patients (12 men and 5 women), with mean age of 12 years and 4 months ± 1 year and 2 months, and bone age corresponding to the growth spurt, as revealed by a hand-wrist radiograph. The appliance was made according to a wax bite registration obtained with 6 mm of initial advancement, and progressive advancements of 2 mm every 2 months, according to individual needs This phase lasted for an average of 13.9 ± 2.1 months. Thereafter, the orthodontic phase (phase II) was performed with pre-adjusted fixed appliance and aimed at leveling and aligning the upper and lower teeth as well as at obtaining functional occlusion with adequate overjet and overbite.
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