Occlusal changes during and after Herbst treatment: a cephalometric investigation

Abstract

The aim of this study was to evaluate quantitatively sagittal, skeletal and dental changes occurring during and after Herbst treatment and relate these changes to alteration in the occlusion. Lateral roentgenograms in centric occlusion were analysed. The sample consisted of 40 Class II, division 1 cases treated with the Herbst appliance for an average period of 7 months. The subjects were reexamined 6 and 12 months post treatment. The results revealed the following: during the treatment period all subjects were treated to Class I or overcorrected Class I or Class III dental arch relationships. Overjet and sagittal molar relationship improved by an average of 6.9 mm and 6.3 mm respectively. This was a result of a 2.2 mm greater mandibular than maxillary growth, a 2.3 mm lingual movement of the maxillary incisors, a 2.4 mm labial movement of the mandibular incisors, a 2.0 mm distal movement of the maxillary molars and a 2.1 mm mesial movement of the mandibular molars. During the post treatment period of 12 months the occlusion settled into Class I in all subjects. Overjet and sagittal molar relationship relapsed by an average of 2.2 mm and 1.7 mm respectively. About 90 per cent of the occlusal relapse occurred during the first 6 months post treatment. In 58 per cent of the subjects the occlusal relapse was exclusively a result of tooth movements while unfavourable maxillary and mandibular jaw growth contributed to the relapse in 42 per cent of the subjects. As Herbst treatment is performed during a relatively short period, the dentition will be in a state of instability after the appliance is removed. Post treatment retention as well as interocclusal adjustments with an activator are therefore recommended.

Efeitos do Jasper Jumper e do aparelho de protração mandibular no tratamento da má oclusão de classe II

“…Pancherz (1981;1982a,b;1985;1997; Com relação ao deslocamento maxilar anterior, é unânime na literatura de que realmente ocorre restrição (PANCHERZ, 1979;1982a;1997;HÄGG, 1985;HANSEN, 1986;URSI, 1993; URSI; MCNAMARA JR; MARTINS, 1999;VALANT;SINCLAIR, 1989 Segundo a maioria das publicações, há um aumento na taxa de crescimento ântero-posterior da mandíbula (MCNAMARA JR; HOWE; DISCHINGER, 1990;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989). Esse aumento do crescimento mandibular ocorre devido à estimulação do crescimento condilar promovida pelo aparelho de Herbst.…”

“…A relação maxilomandibular apresenta uma sensível melhora, devido provavelmente a restrição do crescimento maxilar e a estimulação do crescimento mandibular, segundo vários autores (CROFT et al, 1999;HOWE;DISCHINGER, 1990;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;SCHIAVONI;GRENGA;MACRI, 1992;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989). Pancherz (1979) demonstrou que o aparelho de Herbst não promoveu alterações significantes no componente vertical, comparado ao grupo controle.…”

“…A mandíbula deslocou-se para baixo de maneira paralela, indicando uma harmonia no aumento vertical anterior e posterior (MCNAMARA JR; HOWE; DISCHINGER, 1990;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989). Nahás (2004) também concluiu que o padrão de crescimento craniofacial não foi influenciado pelo tratamento com o Herbst.…”

“…Os incisivos superiores não apresentaram alterações significantes em sua posição (PANCHERZ, 1979;1982b;1985;HANSEN, 1986;VALANT;SINCLAIR, 1989 DISCHINGER, 1990;NAHÁS, 2004;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989).…”

“…Com relação ao aparelho de Herbst promover distalização dos molares superiores, houve unanimidade na literatura com relação à sua efetividade (CROFT et al, 1999;HOWE;DISCHINGER, 1990;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989 (CROFT et al, 1999;HOWE;DISCHINGER, 1990;NAHÁS, 2004;PANCHERZ, 1979;1982b;1985;HANSEN, 1986;URSI, 1993;URSI;MARTINS, 1999;VALANT;SINCLAIR, 1989). Além disso, observaram uma tendência à extrusão, como mostra os estudos de Pancherz (1979), Ursi (1993) e McNamara Jr, Howe e Dischinger (1990).…”