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PURPOSE: To compare the effects of different screw-tightening sequences and torque applications on stresses in implant-supported fixed complete dentures supported by five abutments. MATERIALS AND METHODS: Strain gauges fixed to the abutments were used to test the sequences 2-4-3-1-5; 1-2-3-4-5; 3-2-4-1-5; and 2-5-4-1-3 with direct 10-Ncm torque or progressive torque (5 + 10 Ncm). Data were analyzed using analysis of variance and standardized effect size. RESULTS: No effects of tightening sequence or torque application were found except for the sequence 3-2-4-1-5 and some small to moderate effect sizes. CONCLUSION: Screw-tightening sequences and torque application modes have only a marginal effect on residual stresses.

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STATEMENT OF PROBLEM: Clinical procedures and laboratory processing techniques inevitably induce stress in the implant/abutment/prosthesis system and may have negative effects when different numbers of implants are used. PURPOSE: The purpose of the study was to evaluate the tension on the abutments of implant-supported fixed prostheses and to determine the effect of the application of an esthetic veneer (acrylic resin) and the number of abutments (5 or 4). MATERIAL AND METHODS: Four palladium-silver alloy cast bars were fabricated to simulate implant-supported fixed complete prostheses. Strain gauges were fixed on the abutments to measure the tension before and after the application of the esthetic veneer. The values of tension were measured in models with 5 or 4 abutments. Data were analyzed with a repeated measures ANOVA. RESULTS: No statistically significant differences were found for the main factors (esthetic veneer, P=.22; number of abutments, P=.14) despite the large effect size. CONCLUSIONS: The results of this study suggest that the tension in the abutments of an implant-supported fixed prosthesis is not affected by the application of acrylic resin veneering or by reducing the number of abutments.

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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.

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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.

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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.

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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.

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PURPOSE: This study evaluated the deformation of a metallic framework connected to 15 stone casts fabricated using 3 transfer techniques to determine the most accurate impression procedure. MATERIALS AND METHODS: Five stone casts were made from polyether impressions of an epoxy resin master model for each transfer technique. Group 1 samples were created by the direct splinted technique (square transfer copings splinted with carbon steel pins and autopolymerizing acrylic resin, custom tray); group 2 samples were made by the direct nonsplinted technique (square transfer copings, custom tray); and group 3 samples were fabricated using the indirect technique (tapered transfer copings, custom tray). Sixteen strain gauges were fixed on the framework to measure the degree of framework deformation for each stone cast. Pairs of strain gauges placed opposite each other constituted 1 channel to read deformation (half Wheatstone bridge). Deformation readings were collected at the 4 segments between abutments in 4 directions (anterior, posterior, superior, and inferior). Deformation data were analyzed using analysis of variance and the Tukey test at the .05 and .01 levels of significance. RESULTS: Group 1 samples allowed the most accurate reproduction of analog position compared to the samples made using the other techniques. No significant difference was found between the direct nonsplinted (group 2) and indirect (group 3) techniques. DISCUSSION: Although some studies have evaluated transfer techniques with similar methodology, this study demonstrated the most suitable strain gauge setup to record framework deformations in all directions and simultaneously offset the effects of temperature variation. CONCLUSIONS: The direct splinted technique was the most accurate transfer method for multiple abutments compared to direct nonsplinted and indirect techniques.

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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

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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.

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Esta revisäo teve a finalidade de comparar as vantagens e as desvantagens do uso das tomografias lineares e computadorizadas

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