Princípios biomecânicos do aparelho extrabucal

Abstract

A utilização do aparelho extrabucal no tratamento da má oclusão de Classe II de Angle, exige que os princípios biomecânicos sejam entendidos e aplicados para que o caso clínico seja conduzido de maneira que os efeitos colaterais sejam minimizados e os benéficos maximizados. Para tanto, o ortodontista deve ser capaz de prever os efeitos da inclinação da linha de ação de força e sua relação com os centros de resistência da maxila e dos dentes. Quaisquer movimentos de rotação, inclinação ou translação dos dentes, bem como rotação horária ou anti-horária da maxila e da mandíbula, podem ser previstos e planejados quando o ortodontista conhece os mecanismos que os produzem, e também os efeitos que os diferentes tipos de tração produzem em indivíduos dolicofacial, mesofacial ou braquifacial. Assim, o intuito desse trabalho é apresentar fatores preponderantes e imprescindíveis para a utilização do aparelho extrabucal no tratamento da má oclusão de Classe II de Angle.

Assessment of first molars sagittal and rotational position in Class II, division 1 malocclusion

“…The asymmetric position may determine important aspects regarding the orthodontic mechanics that will be used, such as the correction of rotations, or distalization methods. [9][10][11][12] These procedures may be applied with different intensities in each to obtain an arch with symmetrical positioning of the posterior teeth. 13 With the purpose of carrying out a detailed assessment of teeth positioning, the dental cast analysis is an important tool due to its practicality, reliability and reproducibility.…”

Análise do movimento inicial de molares superiores submetidos a forças extrabucais: estudo 3D

“…15,16 Traction line angulation can be changed only by varying outer bow angle and length. 20,25 It is possible, however, with such changes, to cause extrusive movements that undermine vertical control mechanics, especially when the outer bow is raised to correct distal molar tipping (tip back). In this situation, it is advisable to employ combined traction.…”

“…3 Its use requires knowledge of basic biomechanical concepts, such as center of resistance, tooth rotation and force action lines 14 for monitoring tooth movement during treatment. 20,25 When symmetrically changing the length and/ or angulation of its outer arch, or when applying different force vectors, the impact on dental and skeletal structures can be altered. 20,29 The effects are often undesirable and it is up to orthodontists to reduce such effects by predicting the possible force action line angulations and their relationship with the center of resistance of the tooth to be moved.…”

“…20,29 The effects are often undesirable and it is up to orthodontists to reduce such effects by predicting the possible force action line angulations and their relationship with the center of resistance of the tooth to be moved. 25 The viewing of these side effects has been extensively reported in literature, 1,4,9,17,21,26,29 usually by superimposing profile X-rays. Some studies have shown that a major limitation of this method lies in the difficulty to isolate molar movement without allowing the growth of the basal bones to interfere with the analysis.…”

Tratamiento ortopédico y ortodóncico de una maloclusión clase II división 1 por hábito de succión digital

“…El aparato extraoral es el método de tratamiento por el cual son generadas fuerzas fuera de la cavidad bucal en las regiones cervical, occipital y parietal, que son aplicadas para estabilizar, mover elementos dentarios o dirigir el crecimiento de los huesos del complejo maxilofacial . (3) Cellier usó un apoyo fuera de la boca en la parte posterior y superior para inmovilizar la mandíbula mientras que Kingsley en 1866 fue considerado el precursor del anclaje extra bucal al reducir una protrusión maxilar con este aparato. Kloehn en 1961 uso la región cervical como punto de apoyo .…”