Photoelastic Analysis of Internal Stresses in the Periodontium Created by Occlusal Forces

Glickman, Irving; Roeber, Fred W.; Brion, Monique; Pameijer, Jan H.N.

doi:10.1902/jop.1970.41.1.30

Cited by 82 publications

(60 citation statements)

References 5 publications

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“…Em modelos fotoelásticos que reproduziram estruturas biológicas, nos mesmos locais submetidos à compressão e com formação de franjas, houve reabsorção óssea nos modelos biológicos, após análise histológica dos tecidos. Nos locais submetidos à tração, nos modelos fotoelásticos, houve deposição, ou neoformação óssea, nos modelos biológicos [6,18]. A transparência permite uma visibilidade direta de toda a estrutura sob efeito da força, em direção e intensidade [19].…”

Section: Escolha Da Análise Fotoelásticaunclassified

“…Para gerar resultados quantitativos, é necessária calibração do material fotoelástico, e para tanto é necessário determinar o valor da franja e a ordem do material, pois o valor da franja depende do tipo de material usado, sua espessura, o comprimento de onda da luz empregada e da temperatura do modelo [18], aprofundamento da técnica que está programado para um próximo trabalho. Desta forma, neste trabalho foram avaliadas a direção e distribuição das tensões mecânicas.…”

Section: Direção E Distribuição Das Tensõesunclassified

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Distribuição de tensões em mini-implantes ortodônticos

Dobranszki

Neto

Dobranszki³

et al. 2010

Matéria (Rio J.)

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RESUMOO objetivo deste trabalho foi avaliar a distribuição de tensões na resina em contato com os filetes de roscas de mini-implantes cilíndricos e cônicos, submetidos à carga lateral e torção de inserção. Um modelo fotoelástico foi confeccionado com gelatina transparente, para simular o osso alveolar. O modelo foi observado com um polariscópio plano e fotografado antes e após a ativação dos mini-implantes com força lateral e de inserção. A aplicação de cargas laterais provocou momentos fletores nos mini-implantes, aparecimento de franjas isocromáticas ao longo dos filetes do corpo dos mini-implantes e no ápice. Quando foi aplicado o torque de inserção, verificou-se a concentração de tensões próxima ao ápice. Concluiu-se que:(1) o mini-implante cilíndrico apresentou maior concentração de tensões no ápice, e (2) o mini-implante cônico apresentou maior concentração de tensões nos filetes de rosca apicais.Palavras-chaves: distribuição de tensões, fotoelasticidade, mini-implantes, ancoragem absoluta. Stress distribution in orthodontic mini-implants ABSTRACTThe objective of this study was to evaluate the stress distribution in the resin in contact with the spirals of cylindrical and conical mini-implants, when submitted to lateral load and insertion torsion. A photoelastic model was fabricated using transparent gelatin to simulate the alveolar bone. The model was observed with a plane polariscope and photographically recorded before and after activation of the two screws with a lateral force and torsion. The lateral force application caused bending moments on both miniimplants, with the uprising of fringes or isochromatics, characteristics of stresses, along the threads of the mini-implants and in the apex. When the torsion was exerted in the mini-implants, a great concentration of stress upraised close to the apex. The conclusion was that, comparing conical with cylindrical mini-implants under lateral load, the stresses were similar on the traction sides. The differences appear (1) on the apex, where the cylindrical mini-implant showed a greater concentration of stress, and (2) along the spirals, in the compression side, where the conical mini-implant showed a greater concentration of stress. The greater part of the stress produced by both mini-implants, after torsion load in insertion, were concentrated on the apex. With the cylindrical mini-implant, the greater concentration of tension was close to the apex, while with the conical one, the stresses were distributed along a greater amount of apical threads.

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Section: Escolha Da Análise Fotoelásticaunclassified

Section: Direção E Distribuição Das Tensõesunclassified

Distribuição de tensões em mini-implantes ortodônticos

Dobranszki

Neto

Dobranszki³

et al. 2010

Matéria (Rio J.)

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“…In order to elucidate mechanical changes taking place within a biological system numerous studies like photoelastic [10], strain gauge [11] and laser holographic [12] interference techniques have been attempted. While these approaches have provided some information in precise evaluation of displacement and stress induced in stomatognathic system, it would be impossible to carry them out without actual tissue damage in human beings.…”

Section: Introductionmentioning

confidence: 99%

En-masse Retraction of the Maxillary Anterior Teeth by Applying Force from Four Different Levels – A Finite Element Study

Keluskar

Revankar³

2014

JCDR

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Objective: To find out if it is possible to control maxillary anterior teeth in sagittal and vertical plane during retraction by altering the vertical levels of force application in the posterior region, i.e. identifying the type of movement of the maxillary anterior teeth which occurs when force would be applied from four different levels i.e. High, Medium, and Low pull Implants and from a conventional Molar hook and also to quantify the retraction and intrusion components of force thus setting a guideline for the implant height placement. Materials and Methods:A Finite Element Model of maxillary dentition along with alveolar bone, brackets and wire was developed with defined material properties. The model was analysed to calculate the displacement when force was applied from different levels.Results: From all points of force application, anterior teeth tipped lingually in the sagittal plane, whereas in the vertical plane extrusion was seen when retracted from molar hook and intrusion was seen when retracted from implants. For every mm of apical displacement of implant, the retraction component of force reduces approximately by around 1% and intrusion component of force increases approximately by around 0.3%. Conclusion:Based on the results of this study we can reckon that by changing the position of implant in vertical plane one will have very little effect on the type of tooth movement. As the point of force application moves apically, type of tooth movement in the sagittal plane remained almost constant and in vertical plane intrusion is slightly increased.

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“…Second, since the dens and dental pad are biologic tissues which are asymmetric in the inner part, the bend is nonlinear under external force. Many published reports described different methods, such as the electrometric method (Craig and Peyton, 1967), the photoelastimetric method (Glikeman et al, 1970), laser holographic interferometry (Zhu et al, 1985;Young and Altschuler, 1977), and finite element analysis (Liu et al, 2004;Farah and Craig, 1988). However, the problem of surface contact in chewing and lack of analysis of rotation during chewing continue to limit investigation of the bridge stabilization.…”

Section: Introductionmentioning

confidence: 99%

Stabilization of an abutment under a rigidly fixed bridge by holographical-speckle interferometry

Zhang

Zhou

Liu

et al. 2007

J. Zhejiang Univ. - Sci. B

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Abstract:Objective: There are no detailed reports of three-dimensional measurement of abutment teeth in mastication, because it is knotty to observe the rotation in chewing directly, and inexact to estimate indirectly. This work studies the three-dimensional stability of rigidly fixed bridge under the stresses of distributed loads and concentrated loads by optical method that gives the tip angle and rotation angle calculated directly based on measurement data. Methods: The specimen, taken from a 25-year-old male, was a left mandible without the second premolars and the first molars. As abutments, first premolar and second molar have complete periodontium. The specimen was soaked in formaldehyde solution. The bridge was fixed between two abutment teeth (first premolars and second molars), and the mandible was cemented in a steel box. The load was increased from 0 kg to 23 kg. Laser holographic technique was used to measure the three-dimensional bit shift of the dens, both buccolingual bit shift and mesiodistal bit shift, and determine tip angle and rotation angle. Results: The effects of stress distribution on the rigidly fixed bridge were evaluated, and stabilization of the bridge under the stresses of distributed loads and concentrated loads, respectively, were analyzed. The results showed that the tips of two abutments were very similar, and no distinct difference was observed between the distributed load and the concentrated load. However, the maximum rotation angle for the distributed load was two to four times as large as that for the concentrated load. In the experiment, the tip angle of the abutment teeth was no more than 0.65 degree, and the rotation angle was no more than 0.60 degree. All maximum angles occurred in the second molar. Conclusion: The fixed bridge is considered to be safe. In addition, a method for measuring the rotation angle was provided effectively.

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Photoelastic Analysis of Internal Stresses in the Periodontium Created by Occlusal Forces

Cited by 82 publications

References 5 publications

Distribuição de tensões em mini-implantes ortodônticos

Distribuição de tensões em mini-implantes ortodônticos

En-masse Retraction of the Maxillary Anterior Teeth by Applying Force from Four Different Levels – A Finite Element Study

Stabilization of an abutment under a rigidly fixed bridge by holographical-speckle interferometry

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