ABSTRACT
OBJECTIVE: To evaluate the force systems produced by transpalatal arches (TPAs) activated according to the six classes of geometries described by Burstone and Koenig. MATERIALS AND METHODS: Sixty appliances were tested for first-order activations using a mechanical force testing system. The TPAs were first checked for passivity in sagittal, transverse, and vertical planes at the measuring machine. Then 10 appliances per group were activated using a millimeter template to obtain the six classes of geometries, and the activated appliances were inserted into lingual tubes of the Force System Identification machine that recorded the deactivation forces and moments delivered by both terminal ends of the TPAs. RESULTS: The overall force system with the actual values of forces and moments recorded by each type of activation was illustrated and compared with the mathematical model reported by Burstone and Koenig. Although a great consistency of the direction of forces and moments were observed, the theoretically feasible force systems could not be fully accomplished by the TPA activated for the six classes of geometries. CONCLUSION: The first-order activations of the TPA can deliver predictable force systems in respect to the direction of forces and moments attainable, but some unexpected forces and moments are also produced. Careful clinical monitoring is, therefore, strongly recommended when using this statically indeterminate system.
Subject(s)
Activator Appliances , Orthodontic Appliance Design , Tooth Movement Techniques/instrumentation , Dental Stress Analysis , Humans , Orthodontic Wires , Stainless SteelABSTRACT
Um dos problemas que encontramos na especialidade de Ortodontia é a mordida aberta. Dispositivos extraorais são eficientes, entretanto, dependem da colaboração e tolerância do paciente. O controle vertical por meio de dispositivos intraorais representa uma grande ferramenta clínica. O presente trabalho se propõe apresentar as BTPs modificadas de modo a proporcionar a intrusão do segmento posterior maxilar e realizar um efetivo controle vertical, com giro mandibular anti-horário na terapêutica ortodôntica...
One of the problems observed in Orthodontics is the open bite. Extra-oral devices are effective; however they depend on the patients compliance and collaboration. Vertical control through intra-oral devices represents a great clinical tool. This paper aims at presenting the modified transpalatal bar to provide the intrusion of maxillary posterior segment and perform an effective vertical control, rotating counterclockwise in the mandibular orthodontic therapy...
Subject(s)
Humans , Male , Adolescent , Tooth Movement Techniques , Open BiteABSTRACT
A sobremordida profunda é uma má oclusão de alta prevalência nos indivíduos. Diante disso, um dos grandes desafios desta situação é conseguirmos realizar a montagem da aparatologia ortodôntica fixa no arco inferior como um recurso colaborador à solução do problema. Em virtude deste trespasse vertical acentuado dificultar este procedimento, lança-se mão de dispositivos complementares a fim de promover o levante de mordida e com isso a possibilidade de executar a mecânica para o arco inferior. Sendo assim, propõe-se por meio deste artigo relatar uma variável da Barra Transpalatina que permite a montagem do aparelho fixo inferior em casos onde existe uma sobremordida profunda.
Deep overbite is a malocclusion with high prevalence in individuals. Thus the major challenge in cases of deep overbite, is to place the fixed orthodontic appliance in the lower arch as a solution to this problem. Since the pronounced overbite hinder this procedure, additional devices are applied to lift the bite and thereby enabling lower arch mechanics. Thus, this paper aimed at presenting a variant of the transpalatal bar that permits the installation of lower fixed appliance in cases of deep overbite.
Subject(s)
Orthodontic Appliances , OrthodonticsABSTRACT
OBJECTIVE: The main goal of this study was to optimize unilateral molar rotation correction by modifying a trans-palatal arch (TPA) design using the finite element method. DESIGN: Three-dimensional analysis of different TPA designs was carried out using the finite element method. SETTING: Department of Orthodontics, Tehran University of Medical Sciences, Iran. MATERIAL AND METHODS: For this investigation, 13 three-dimensional finite element models were produced for different TPA designs without pre-activation bends. Each model contained a palatal bar and two tubes. Optimizing unilateral molar rotations was achieved by five separate different paths: incorporating U-loop(s), 'R' loop(s) or helix/helices, a reverse action of the helix/helices and adding a straight wire to the design. The mesial part of the left side tube was displaced 0·1, 0·25, 0·5 and 1 mm, successively towards the midline, simulating palatal bar tab engagement in a mesio-palatal rotated maxillary left molar. The mesio-distal force, moment and energy produced in the normal side (right) molar were recorded for each of the models. RESULTS: Findings showed that in all designs, the associated mesializing force was lower than that seen in the traditional design and the moment showed an increasing pattern when compared with a simple palatal bar. Regarding energy levels, the same increasing pattern was observed in the designs between activations of 0·1 and 1·0 mm. CONCLUSION: According to our optimized system, the TPA design with the highest energy and moment, but the lowest mesializing force associated with derotating a maxillary molar tooth was a parallel wire II design (i.e. adding a straight wire).
Subject(s)
Finite Element Analysis , Imaging, Three-Dimensional/methods , Malocclusion/therapy , Molar/pathology , Orthodontic Appliance Design , Tooth Movement Techniques/instrumentation , Biomechanical Phenomena , Dental Alloys/chemistry , Humans , Orthodontic Wires , Rotation , Stainless Steel/chemistry , Stress, MechanicalABSTRACT
La distalización es un tratamiento común en la corrección de las maloclusiones clase II, para lo cualse han diseñado dispositivos dento-soportados como el péndulo, pero con efectos colaterales como la mesialización de premolares y vestibularización de incisivos superiores, actualmente se utilizandiferentes sistemas oseo-soportados eliminando estas reacciones.
Distalization is a common treatment for the correction of class II malocclusion; several tooth supportedappliances such as the pendulum have been designed and used with side effects like mesializationof premolars and labialization of upper incisors; currently different bone supported systems arebeing used in order to eliminate this reaction.
