Prótese total mandibular imediata sobre implantes cone-morse / Immediate mandibular full arch prosthesis with Morse taper connection implant: clinical case

A perda total dos dentes ainda é um problema enfrentado por grande parcela da população. Nesse sentido, a Odontologia vem desenvolvendo novos métodos para a reabilitação desses pacientes. As próteses totais mucossuportadas foram amplamente utilizadas sem apresentarem, no entanto, estabilidade e retenção satisfatórias, principalmente na mandíbula. Com os estudos desenvolvidos por Brånemark, que culminaram com o aparecimento dos implantes osseointegráveis, um novo conceito de tratamento de pacientes desdentados totais surgiu: próteses totais implantossuportadas. A partir desse conceito, modificações foram realizadas no protocolo original com o intuito de tornar o tratamento mais rápido, efetivo, barato e menos traumático. Assim, pesquisas foram desenvolvidas para viabilizar o carregamento imediato dos implantes. Outro novo conceito que busca a melhora dos resultados em reabilitações orais é o sistema cone-morse, que apresenta maior resistência mecânica, melhor distribuição e transmissão de forças ao longo do implante para o tecido ósseo, redução do gap, com diminuição da possiblidade de invasão bacteriana na interface do implante intermediário, além da redução do afrouxamento e fraturas de parafusos. Fundamentado nessas considerações, este artigo tem como objetivo apresentar um caso clínico de reabilitação com prótese total imediata implantossuportada por implantes do tipo cone-morse na mandíbula. O resultado mostrou-se bastante satisfatório tanto em relação à estética quanto à função e, principalmente, ao conforto do paciente.

The edentulous condition is still a problem faced by most of the population. In this sense, dentistry has developed new methods for the rehabilitation of these patients. Initially, mucoussupported total prostheses have been widely used however without demonstrating satisfactory stability and retention, particularly in the jaw. With the studies developed by Brånemark culminating in the appearance of modern dental implants, a new concept emerged to treat edentulous patients: total implant-supported fixed prosthesis. From this concept, modifications were made in the original protocol in order to make the treatment faster, effective, inexpensive, and less traumatic. Thus, research has been developed to enable the immediate implant activation. Another new concept that aims to provide better results in the oral rehabilitation is the Morse taper system that has greater mechanical strength, better force distribution and transmission along the implant to the bone tissue, reducing the gap with less chance of bacterial invasion in the prosthetic-implant interface, and still with less loosening and screw fractures. Based on these considerations, this article aims to present a case of an immediate implant-supported mandibular total prosthesis on Morse taper implants. The result was quite satisfactory both in relation to aesthetics, function, but especially for patient's comfort.

Efeito do desafio ácido nas propriedades superficiais das camadas externa e interna de dentes acrílicos reforçados / Effect of acid challenge on the surface properties of external and internal layers of cross-linked acrylic teeth

Introdução: Os dentes acrílicos artificiais devem apresentar característica de resistência aos ácidos, a fim de assegurar a manutenção de suas propriedades, ao longo de sua vida útil. Entretanto, não há estudos disponíveis na literatura pertinente sobre as propriedades superficiais de dureza e rugosidade das diferentes camadas de resina acrílica que compõem os dentes artificiais submetidos a ensaios de erosão simulada. Objetivo: Avaliar a dureza e rugosidade superficiais das camadas externa e interna de dentes artificiais acrílicos reforçados submetidos a desafio ácido. Metodologia: Molares (SR Postaris e Trilux) seccionados transversalmente foram avaliados inicialmente quanto à dureza Vickers e rugosidade. Esses ensaios foram repetidos após metade das amostras de cada tipo de dente (n=10) ser imersa em água destilada (controle) e outra metade em vinagre durante 15 min/dia por 28 dias. Os resultados foram analisados por ANOVA 2-critérios e teste de Tukey (α=0,05). Resultado: A dureza inicial da camada externa dos dois diferentes tipos de dente não sofreu alteração significativa pelo desafio ácido (p>0,05) e a imersão em vinagre não causou efeito deletério à dureza inicial da camada interna dos dois tipos de dentes avaliados (p>0,05). Após 28 dias, a rugosidade inicial de ambos os tipos de dentes estudados, para as duas camadas, não foi alterada com água ou vinagre (p>0,05). Conclusão: Os dentes acrílicos reforçados foram resistentes ao desafio ácido uma vez que suas camadas interna e externa não apresentaram alteração significativa de dureza e rugosidade superficiais.

Introduction: Artificial acrylic teeth must be resistant to acids for ensure the maintenance of their properties throughout their useful life. However, there are no studies available in the literature about the surface properties of hardness and roughness of the different layers of acrylic resin that make up the artificial teeth submitted to simulated erosion tests. Objective: To evaluate the surface hardness and roughness of external and internal layers of artificial cross-linked acrylic teeth submitted to acid challenge. Methodology: First molars (SR Postaris and Trilux) transversely sectioned had its Vickers hardness and roughness initially evaluated. These tests were repeated after half of the tooth samples (n=10) be immersed into distilled water (control) and half in vinegar during 15 min/day for 28 days. Data were analyzed using 2-way ANOVA and Tukey's test (α=0.05). Result: The initial external layers hardness of both was not significantly altered by acid challenge (p> 0.05) and the immersion in vinegar caused no deleterious effect on the initial internal layers hardness of the two tested teeth (p>0.05). After 28 days, the initial roughness of both teeth evaluated for the two layers was not affected by water or vinegar (p>0.05). Conclusion: The reinforced acrylic teeth were resistant to acid challenge since its internal and external layers showed no significant change in hardness and surface roughness.

Internal fit of two all-ceramic systems and metal-ceramic crowns.

OBJECTIVES: The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA--In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP--IPS e.max ZirCAD), and metal-ceramic (MC--Ni-Cr alloy) crowns. MATERIAL AND METHODS: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey's multiple comparison test (p<0.05). RESULTS: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. CONCLUSIONS: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

Internal fit of two all-ceramic systems and metal-ceramic crowns

OBJECTIVES: The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. MATERIAL AND METHODS: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey ’s multiple comparison test (p<0.05). RESULTS: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. CONCLUSIONS: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

Fatores de risco em implantes dentais: uma revisão crítica / Risk factors in implant dentistry: a critical review

O sucesso dos implantes está baseado em uma adequada técnica, uma correta seleção de pacientes, uma cirurgia cuidadosa, restaurações provisórias e os cuidados pósoperatórios e de suporte. Embora a terapia de implante já esteja bem estabelecida e previsível, complicações precoces e/ou tardias são possíveis. Os autores estabeleceram uma estratégia de busca na base de dados MEDLINE (PubMed) entre 1983 e 2011. Foi realizado combinações de palavraschave diferentes, incluindo os termos implantes dentários, fatores de risco biomecânicos e falhas no planejamento de tratamento. Depois de eliminando duplas citações, 98 resumos completos de textos de artigos e 32 artigos foram incluídos. O objetivo deste artigo é ressaltar a importância dos fatores de risco relacionados à implantodontia bem como possíveis complicações. Estes fatores parecem ser na maioria das vezes, relacionadas a causas de natureza iatrogênicas e em parte relacionada com o plano de tratamento. Por isso, especial atenção por parte dos profissionais se faz necessário como correta documentação e uma estratégia de tratamento pré, trans e pós-operatória para que situações indesejadas sejam evitadas.

This article describes the many failures and complications that can occur when using implants to support restorations. Most of these failures can be prevented with proper patient selection and treatment planning. Although implant therapy is already well established and predictable early complications and / or delayed are possible. The authors established a search strategy in MEDLINE (PubMed) from 1983 to 2011. Combinations was carried different keywords, including terms dental implants, biomechanical risk factors and failures in treatment planning. After eliminating double quotes, 98 abstracts articles and 27 articles full text were included. The purpose of this review is to summarize the critical factors of risk involved to implant dentistry as well as possible complications. These factors seem to be mostly related to iatrogenic causes of nature and partly related to the treatment plan. Therefore, special attention from professionals as is necessary correct documentation and a treatment strategy before, during and post-operative so that unwanted situations can be avoided.

Aspectos periodontais relacionados ao tratamento reabilitador – revisão de literatura / Periodontal aspects related to rehabilitation treatment – a literature review

A interface restauração e tecidos periodontais representa o limite de atuação entre protesista e periodontista sendo essa região área de interesse fundamental no tratamento odontológico. O conhecimento dos parâmetros periodontais específicos, como a avaliação das distâncias biológicas, para sítios de prótese fixa sobre dentes ou sobre implantes deverá ser um procedimento de rotina para os profissionais que se dedicam a essa área. Situações clínicas com términos de preparos intrassulculares nem sempre permitem realizar procedimentos restauradores dentro dos adequados padrões técnicos e biológicos. É consenso na literatura que a qualidade de uma prótese pode ser avaliada pela resposta dos tecidos periodontais ao redor de pilares protéticos ou implantes dentários. Portanto, o conhecimento da anatomia do periodonto é importante para o restabelecimento prévio da saúde periodontal e fundamental para qualquer tratamento restaurador, sendo importante pré-requisito para o sucesso clínico a longo prazo dos tratamentos protéticos.

The relationship between periodontal tissues and restorative dentistry represents the performance limitation between periodontists and prosthodontists and this interface is an area of fundamental interest in dental treatment. Specific knowledge of periodontal parameters, such as evaluation of biological distances to areas on fixed prosthesis or implant, should be routine for the professionals who are dedicated to this area. Clinical situations with preparations of subgingival margin finish frequently do not enable performance restoration procedures within the appropriate technical and biological standards. There is a consensus in the literature that the quality of prosthesis can be evaluated by the response of periodontal tissues around dental implants or teeth. Therefore, knowledge of the anatomy of the periodontium is important to restore periodontal health and fundamental for any restorative treatment, and particularly to ensure long-term clinical success.

In vitro wear resistance of three types of polymethyl methacrylate denture teeth.

The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when opposed by a ceramic antagonist. The maxillary canines (n=10) of 3 PMMA denture teeth (Trubyte Biotone, cross-linked PMMA; Trilux, highly cross-linked IPN (interpenetrating polymer network)-PMMA; and Vivodent, highly cross-linked PMMA) were secured in an in vitro 2-body wear-testing apparatus that produced sliding contact of the specimens (4.5 cycles/s, sliding distance of 20 mm, under 37 degrees C running water) against glazed or airborne particle abraded ceramic. Wear resistance was measured as height loss (mm) under 300 g (sliding force) after 100,000 cycles, using a digital measuring microscope. Mean values were analyzed by 2-way ANOVA and Tukey's test (a=0.05). The wear of Trubyte Biotone (0.93 +/- 0.14 mm) was significantly higher than that of both other types of teeth tested against abraded ceramic (p<0.05). The Vivodent tooth (0.64 +/- 0.17 mm) exhibited the best wear resistance among the denture teeth tested against airborne particle abraded ceramic. There were no statistically significant differences (p>0.05) in wear among the 3 denture teeth evaluated against glazed ceramic. Trilux and Vivodent teeth tested against either glazed or airborne particle abraded ceramic did not differ significantly from each other (p<0.05). All teeth showed significantly more wear against airborne particle abraded ceramic than against glazed ceramic (p<0.05). In conclusion, the three types of PMMA denture teeth presented significantly different wear resistance against the abraded ceramic. The high-strength PMMA denture teeth were more wear-resistant than the conventional PMMA denture tooth.

In vitro wear resistance of three types of polymethyl methacrylate denture teeth

The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when opposed by a ceramic antagonist. The maxillary canines (n=10) of 3 PMMA denture teeth (Trubyte Biotone, cross-linked PMMA; Trilux, highly cross-linked IPN (interpenetrating polymer network)-PMMA; and Vivodent, highly cross-linked PMMA) were secured in an in vitro 2-body wear-testing apparatus that produced sliding contact of the specimens (4.5 cycles/s, sliding distance of 20 mm, under 37°C running water) against glazed or airborne particle abraded ceramic. Wear resistance was measured as height loss (mm) under 300 g (sliding force) after 100,000 cycles, using a digital measuring microscope. Mean values were analyzed by 2-way ANOVA and Tukey’s test (á=0.05). The wear of Trubyte Biotone (0.93 ± 0.14 mm) was significantly higher than that of both other types of teeth tested against abraded ceramic (p<0.05). The Vivodent tooth (0.64 ± 0.17 mm) exhibited the best wear resistance among the denture teeth tested against airborne particle abraded ceramic. There were no statistically significant differences (p>0.05) in wear among the 3 denture teeth evaluated against glazed ceramic. Trilux and Vivodent teeth tested against either glazed or airborne particle abraded ceramic did not differ significantly from each other (p<0.05). All teeth showed significantly more wear against airborne particle abraded ceramic than against glazed ceramic (p<0.05). In conclusion, the three types of PMMA denture teeth presented significantly different wear resistance against the abraded ceramic. The high-strength PMMA denture teeth were more wear-resistant than the conventional PMMA denture tooth.

Influência da temperatura final do ciclo de aquecimento do revestimento na fluidez e na resistência à tração do Ti c.p. e da liga Ti-6AI-4V / Influence of the final temperature of investment healting on the casting and tensile strength of CP Ti and Ti-6AI-4V alloy

A suposição de que temperaturas mais elevadas do revestimento possam melhorar a fluidez sem alterar as propriedades mecânicas do titânio e suas ligas, determinou a realização deste trabalho. O objetivo do trabalho foi avaliar o efeito da elevação da temperatura do revestimento na fluidez e na resistência à tração do Ti c.p. e da liga Ti-6AI-4V fundidos. Para o teste de fluidez, os corpos-de-prova foram confeccionados a partir de uma tela de nylon de 20 x 20 mm de comprimento com filamentos de 0,7mm de espessura. Para o teste de tração, corpos-de-prova foram confeccionados na forma de halteres com 3,0 mm no segmento central e 42 mm de comprimento. Para ambos os ensaior os corpos-de-prova foram incluidos em revestimento Rematitan Plus e fundidos em uma máquina de fundição Discovery. Foram confeccionados 30 corpos-de-prova para cada teste, sendo 5 corpos-de-prova para cada uma das três temperaturas do revestimento: 430ºC (grupo controle); 480 e 530ºC. O teste de fluidez foi realizado medindo-se a extensão total dos filamentos do padrão original utilizando-se o programa de análise de imagem (Leica Qwin, Leica) totalizando 284 mm e comparado com os padrões fundidos. O ensaio de tração foi realizado...