ABSTRACT
OBJECTIVE: This study aimed to evaluate the bending moments, and compressive and tensile forces in implant-supported prostheses with three, four or five abutments. MATERIAL AND METHODS: Ten Pd-Ag frameworks were tested over two master models with: 1) parallel vertical implants, and 2) tilted distal implants. Strain gauges were fixed on the abutments of each master model to measure the deformation when a static load of 50 N was applied on the cantilever (15 mm). The deformation values were measured when the metallic frameworks were tested over three, four or five abutments, and transformed into force and bending moment values. Data were analyzed by ANOVA and Tukey's test for multiple comparisons at 5% level of significance. RESULTS: Abutment #1 (adjacent to the cantilever) had the highest values of force and sagittal bending moment for all tests with three, four or five abutments. Independently from the number of abutments, axial force in abutment #1 was higher in the vertical model than in the tilted model. Total moment was higher with three abutments than with four or five abutments. Independently from the inclination of implants, the mean force with four or five abutments was lower than that with three abutments. CONCLUSION: The results suggest that in the set-ups with four or five abutments tilted distal implants reduced axial force and did not increase bending moments.
Subject(s)
Dental Abutments , Dental Implants , Dental Prosthesis Design , Dental Prosthesis, Implant-Supported , Analysis of Variance , Biomechanical Phenomena , Compressive Strength , Dental Implantation, Endosseous , Dental Stress Analysis , Elasticity , Humans , Models, Dental , Models, Structural , Pliability , Statistics, Nonparametric , Tensile StrengthABSTRACT
OBJECTIVE: This study aimed to evaluate the bending moments, and compressive and tensile forces in implant-supported prostheses with three, four or five abutments. MATERIAL AND METHODS: Ten Pd-Ag frameworks were tested over two master models with: 1) parallel vertical implants, and 2) tilted distal implants. Strain gauges were fixed on the abutments of each master model to measure the deformation when a static load of 50 N was applied on the cantilever (15 mm). The deformation values were measured when the metallic frameworks were tested over three, four or five abutments, and transformed into force and bending moment values. Data were analyzed by ANOVA and Tukey's test for multiple comparisons at 5 percent level of significance. RESULTS: Abutment #1 (adjacent to the cantilever) had the highest values of force and sagittal bending moment for all tests with three, four or five abutments. Independently from the number of abutments, axial force in abutment #1 was higher in the vertical model than in the tilted model. Total moment was higher with three abutments than with four or five abutments. Independently from the inclination of implants, the mean force with four or five abutments was lower than that with three abutments. CONCLUSION: The results suggest that in the set-ups with four or five abutments tilted distal implants reduced axial force and did not increase bending moments.
Subject(s)
Humans , Dental Abutments , Dental Implants , Dental Prosthesis Design , Dental Prosthesis, Implant-Supported , Analysis of Variance , Biomechanical Phenomena , Compressive Strength , Dental Implantation, Endosseous , Models, Dental , Dental Stress Analysis , Elasticity , Models, Structural , Pliability , Statistics, Nonparametric , Tensile StrengthABSTRACT
Purpose: To assess the magnitude and distribution of axial forces and bending moments in abutments as a function of cantilever length and inclination of implants. Methods: Ten metallic bars simulated frameworks of fixed implant-supported prosthesis over two master models with five implants: one with all implants straight and parallel (n=5) and one with the two distal implants tilted (n=5). Strain gauges were fixed on abutments to measure deformation when a 50N-load was applied on the cantilever at 10, 15, and 20mm-distance from the distal abutment. Deformation values were transformed into axial force and bending moment and analyzed by ANOVA and Tukey test (α = 5%). Results: Comparing 10mm- to 20mm-cantilever, there was an increase of approximately 50% for axial force and of 70% for saggital bending moment. On the abutment adjacent to the cantilever, the axial force in the inclined model was 70% lower than in the straight model, and bending moments did not vary. Conclusion: The results suggest that the inclination of distal implants does not have any deleterious biomechanical effect on abutments of the tested models and may reduce the cantilever effect on force magnitude.
Objetivo: Avaliar a magnitude e a distribuição de forças axiais e momentos fletores em pilares em função da extensão do cantilever e da inclinação dos implantes. Metodologia: Dez barras metálicas simularam infraestruturas de prótese fixa implantossuportada sobre dois modelos mestre com 5 implantes: um modelo com todos os implantes retos e paralelos (n=5) e um com os dois implantes distais inclinados (n=5). Extensômetros foram fixados nos pilares para medir sua deformação quando uma carga de 50N foi aplicada no cantilever a 10, 15 e 20 mm do implante distal. Os valores de deformação foram convertidos em força axial e momento fletor e analisados por ANOVA e teste de Tukey (α = 5%). Resultados: Comparando-se as distâncias de 10 e 20 mm, houve um aumento de aproximadamente 50% da força axial e de 70% do momento fletor sagital. No pilar adjacente ao cantilever, a força axial no modelo com implantes inclinados foi 70% menor que no modelo com implantes retos, e os momentos fletores não variaram. Conclusão: Os resultados sugerem que a inclinação dos implantes distais não promoveu nenhum efeito deletério sobre os pilares nos modelos testados e pode reduzir o efeito do cantilever na magnitude da força.
Subject(s)
Dental Implants , Dental Prosthesis, Implant-Supported , Biomechanical PhenomenaABSTRACT
Os pilares personalizados, preparados individualmente para cada situação, vêm sendo cada vez mais utilizados pelos odontólogos devido ao fato de minimizarem problemas de angulação e alinhamento de implantes dando à coroa um perfil de emergência mais natural. O presente estudo relata um caso clínico onde foram utilizados pilares protéticos tipo UCLA personalizados para otimizar função e estética numa reabilitação protética.
Subject(s)
Humans , Female , Aged , Dental Prosthesis, Implant-Supported , Esthetics, Dental , OsseointegrationABSTRACT
A substituição de um dente perdido apresenta uma variedade de alternativas terapêuticas, com vantagens e desvantagens de custo financeiro, biológico, mecânico e estético. Neste artigo, apresentamos uso de um sistema cerâmico livre de metal, IPS Empress 2, como alternativa para a construção de prótese fixa para a reabilitação de dentes anteriores e posteriores perdidos. As peças protéticas foram suportadas por preparos parciais, com resultados estéticos, funcionais e biológicos bastante aceitáveis, preenchendo as necessidades locais do paciente
Subject(s)
Humans , Female , Adult , RehabilitationABSTRACT
As conseqüências ao sistema estomatognático, devido às alterações na dimensão vertical de oclusão, tem sido uma questão de controvérsia durante décadas. Estudos recentes têm-se mostrado contrários a uma tendência tradicional de que um aumento da dimensão vertical de oclusão (DVO) pode levar a desordens temporomandibulares (DTM). O conhecimento científico atual suporta a hipótese de que moderadas alterações na DVO não parecem ser deletérias ao sistema mastigatório, desde que a estabilidade oclusal seja alcançada.
Subject(s)
Humans , Male , Female , Vertical Dimension , Dental Occlusion , Stomatognathic System , Temporomandibular Joint DisordersABSTRACT
Esta revisäo teve a finalidade de comparar as vantagens e as desvantagens do uso das tomografias lineares e computadorizadas
