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Comparative Study
. 2014 Jan-Feb;19(1):36-45.
doi: 10.1590/2176-9451.19.1.036-045.oar.

Dentoskeletal effects of Class II malocclusion treatment with the Twin Block appliance in a Brazilian sample: a prospective study

Luciano Zilio Saikoski, Rodrigo Hermont Cançado, Fabrício Pinelli Valarelli, Karina Maria Salvatore de Freitas
Comparative Study

Dentoskeletal effects of Class II malocclusion treatment with the Twin Block appliance in a Brazilian sample: a prospective study

Luciano Zilio Saikoski et al. Dental Press J Orthod. 2014 Jan-Feb.

Abstract
in English, Portuguese

Objective: The aim of this study was to assess the dentoskeletal effects of Class II malocclusion treatment performed with the Twin Block appliance.

Methods: The experimental group comprised 20 individuals with initial mean age of 11.76 years and treated for a period of 1.13 years. The control group comprised 25 individuals with initial mean age of 11.39 years and a follow-up period of 1.07 years. Lateral cephalograms were taken at treatment onset and completion to assess treatment outcomes. Intergroup comparison was performed by means of the chi-square and independent t tests.

Results: The Twin Block appliance did not show significant effects on the maxillary component. The mandibular component showed a statistically significant increase in the effective mandibular length (Co-Gn) and significant improvement in the maxillomandibular relationship. The maxillary and mandibular dentoalveolar components presented a significant inclination of anterior teeth in both arches. The maxillary incisors were lingually tipped and retruded, while the mandibular incisors were labially tipped and protruded.

Conclusions: The Twin Block appliance has great effectiveness for correction of skeletal Class II malocclusion in individuals with growth potential. Most changes are of dentoalveolar nature with a large component of tooth inclination associated with a significant skeletal effect on the mandible.

Objetivo: avaliar os efeitos dentoesqueléticos do tratamento da má oclusão de Classe II com o aparelho Twin Block comparado a um grupo controle.

Métodos: o grupo experimental foi composto por 20 pacientes com idade inicial média de 11,76 anos e que foram tratados por um período de 1,13 anos. O grupo controle foi composto por 25 indivíduos com idade inicial média de 11,39 anos e que foram acompanhados por um período de 1,07 anos. Telerradiografias em norma lateral foram obtidas ao início e final do tratamento para avaliar as alterações decorrentes do tratamento. A comparação intergrupos foi realizada por meio do teste qui-quadrado e do teste t independente.

Resultados: o aparelho Twin Block não apresentou alterações significativas no componente maxilar. O componente mandibular revelou um aumento estatisticamente significativo do crescimento efetivo da mandíbula (Co-Gn) e uma melhora significativa da relação existente entre as bases ósseas. Os componentes dentoalveolar superior e inferior apresentaram um significativo componente de inclinação dos dentes anteriores em ambas as arcadas. Os incisivos superiores foram inclinados para lingual e retruídos, ao passo que os incisivos inferiores foram inclinados para vestibular e protruídos.

Conclusões: o aparelho Twin Block apresenta grande efetividade na correção da má oclusão de Classe II esquelética em pacientes em fase de crescimento. A maior parte das alterações ocorridas é de natureza dentoalveolar, com um grande componente de inclinação dentária associado a um significativo efeito esquelético na mandíbula.

Keywords: Angle Class II malocclusion; Functional orthodontic appliances; Prospective studies; Skull circumference; Treatment outcome.

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Figures

Figure 1
Figure 1
Modified Twin Block appliance.
Figure 2
Figure 2
Twin Block appliance in use - A) Right lateral view. B) Frontal view. C) Left lateral view.
Figure 3
Figure 3
Skeletal angular cephalometric measurements: 1) SNA; 2) SNB; 3) ANB; 4) SN.GoMe; 5) SN.GoGn; 6) SN.Ocl; 7) FMA.
Figure 4
Figure 4
Linear skeletal cephalometric measurements: 8) A-Nperp; 9) Co-A; 10) P-Nperp; 11) Co-Gn ;12) Wits; 13) LAFH.
Figure 5
Figure 5
Angular dental cephalometric measurements: 14) 1.NA; 15) 1.PP; 16) 1.NB; 17) IMPA.
Figure 6
Figure 6
Linear dental cephalometric measurements: 18) 1-NA; 19) 1-Aperp; 20) 1-PP; 21) 1-NB; 22) 1-AP; 23) overjet; 24) overbite; 25) molar relationship.
See this image and copyright information in PMC

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