This study was designed to investigate the effect of adding headgear to the Herbst appliance and the retainer, respectively. The material comprised 2 samples of consecutively treated patients with skeletal Class II malocclusions. The first sample of 22 patients (mean age, 13.2 years) was treated with high-pull headgear Herbst appliance followed by a headgear activator as a retainer, and the second sample of 14 patients (mean age, 12.9 years) was treated with Herbst appliance and an Andresen activator for retention. In both groups, the Herbst appliance was a cast silver splint type with step-by-step advancement of the mandible. Before treatment, there were no significant differences in dentofacial morphology between the groups. Changes during treatment and retention were assessed from lateral cephalograms obtained at start of treatment, after 6 months of treatment, end of treatment (12 months of treatment), and after 6 months of retention. The results showed that the maxillary forward growth was more restrained after 6 months and increasingly more during the 12 months of treatment in the headgear Herbst group, resulting in greater improvement of the jaw-base relationship in that group. The maxilla tilted in the Herbst group but not in the headgear Herbst group. During retention, the positive skeletal changes achieved during active treatment were maintained with the headgear activator, whereas with the Andresen activator there was partial relapse. The overjet correction was similar in both groups, being 9.0 and 9.7 mm, respectively. With the combined headgear concept, 70% of the overjet correction was caused by skeletal changes, whereas in the other group the skeletal contribution was less than 30%. In conclusion, adding headgear to the Herbst resulted in increased orthopedic effect on the maxilla and larger improvement of the jaw-base relationship. The choice of the retention device was critical; the headgear activator maintained the treatment results, whereas the Andresen activator had a negative effect and should not be used as a retainer after Herbst treatment.
"A previous study of Herbst treatment showed that acceleration of mandibular growth only occurred during the initial 6-month phase of treatment, and after 6 more months by guest on May 14, 2011 ejo.oxfordjournals.org Downloaded from of extended treatment mandibular growth did not differ from normal growth, a level which was maintained during 6 months of retention with a HGA ( Hägg et al. , 2003 ). A recent experimental study demonstrated that suffi cient time after forward positioning with a fi xed jumping device was necessary to allow the newly formed condylar bone to mature and become stable, and hence enable normal growth to be maintained post-treatment ( Chayanupatkul et al. , 2003 ). "
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the effects of the headgear activator (HGA) and Herbst appliance during active treatment and retention and at follow-up in children with a skeletal Class II malocclusion. The two groups comprised 16 consecutive male patients (mean age 11.6 +/- 1.42 years) treated with a HGA and 16 male patients (mean age 12.6 +/- 1.13 years) treated with a Herbst appliance and Andresen activator (HAA) sampled from a larger pool using similar selection criteria. Growth data were obtained for the two groups. Lateral cephalograms taken at the start, after 6 months of treatment, after 12 months of active treatment or 6 months of retention, and at the 24-month follow-up were analysed. The total changes over the whole observation period (T0-T3) did not differ significantly between the groups; there was, however, a statistically significant increase in jaw prognathism (P < 0.05) and improvement of the molar relationship (P < 0.05) in the HAA group as compared with the HGA group. During the initial treatment phase (T0-T1), the overall treatment effects were statistically more pronounced in the HAA group than in the HGA group. Despite significant differences in treatment effects and changes between the two devices, there were no significant overall changes at follow-up except for the prognathism, i.e. maxillary prognathism decreased with treatment with the HGA while mandibulars prognathism continued to increase with HAA treatment.
The European Journal of Orthodontics 12/2006; 28(6):594-604. DOI:10.1093/ejo/cjl052 · 1.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This case report describes the treatment of a 12-year-old Chinese boy with a Class II skeletal profile, an extreme overjet, and a retrusive mandible. The patient was teased at school because of his appearance, and he was experiencing negative psychosocial impacts, including shyness and falling grades. Orthodontic treatment had a positive psychosocial impact on his life over a period of 10 years. The advantages of using functional appliances are highlighted in this report.
American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 11/2006; 130(4):540-8. DOI:10.1016/j.ajodo.2005.06.019 · 1.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to compare the effects of stepwise mandibular advancement versus maximum jumping and extended treatment versus early retention. The material was obtained prospectively and consisted of lateral cephalograms taken at the start (T0), after initial (T1), and at the end (T2) of treatment, from two groups of consecutively treated skeletal Class II patients who had undergone therapy with headgear activators. The first headgear activator group, HGA-S (n=24; mean age 11.9 +/- 1.2 years), was treated for 13 months and had 4-mm mandibular advancement every 3 months. The second headgear activator group, HGA-M (n=31; mean age 11.2 +/- 1.5 years), had maximum jumping, 6-8 mm interincisal opening, for a total of 15.4 months, and with reduced wear for the last 6.9 months. The dropout over 12 months was 41 and 46 per cent, respectively. Pre-treatment growth changes were obtained as a reference. An independent t-test was used to determine differences in baseline dentofacial morphology between the groups, a paired t-test for intra-group comparisons, and an independent t-test to evaluate differences between the groups. The results, in both groups, showed enhanced mandibular prognathism during the initial phase (T0-T1), followed by normal growth (T1-T2), and lower face height enhancement throughout treatment (T0-T2). For both groups, the mandibular plane and occlusal angle increased, possibly enhanced by 'extrusion' of the lower molars. For both groups, maxillary forward growth was restrained only during the initial phase, but the effect remained significant at T2 for the HGA-S group. In the HGA-M group, the lower incisors were protruded, while in the HGA-S group, they were unaffected. The findings indicate that both modes of mandibular jumping resulted in skeletal and dental effects. The length of active treatment seemed to be decisive in maintaining the treatment effects; stepwise advancement had less dental effects.
The European Journal of Orthodontics 07/2007; 29(3):283-93. DOI:10.1093/ejo/cjm018 · 1.48 Impact Factor
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