Dispositivo acrílico simples para medir as alterações nos tecidos moles da maxila após procedimentos implantares ou restauradores protético-periodontais / A simple acrylic device to measure maxillary soft tissue alterations after implant and/or restorative periodontal and prosthetic procedures

Alterações nos tecidos moles, na zona estética, podem ocorrer por procedimentos restauradores associados ou não à Implantodontia. Os autores propuseram um dispositivo acrílico simples associado a uma sonda periodontal, para verificação destes níveis em todos os momentos do tratamento reabilitador. O dispositivo em questão também pode ser desenhado e confeccionado em qualquer sistema CAD/CAM.

Soft tissue changes in the esthetic zone can occur after restorative procedures associated or not to implant dentistry. The authors describe a simple acrylic device associated to a periodontal probe to verify those levels during all treatment procedure steps. Also, this device can be design and milled at any CAD/CAM system.

Considerações importantes para uso dos implantes dentários na reabilitação oral de pacientes com desgaste oclusal severo, mordida cruzada e bruxismo: 26 anos de acompanhamento e reflexões

A reabilitação oral busca equilibrar dentes, sistema muscular e ATMs. Entretanto, é necessário escolher estrategicamente quais elementos entrariam no projeto da prótese. Este pode ser um processo demorado, que começa com a colocação das coroas provisórias para verificação dos aspectos estéticos e fonéticos. Ainda, o restabelecimento da dimensão vertical do paciente é fundamental e deve ser feito antes de qualquer terapia invasiva. Nesta fase, por exemplo, é possível detectar hábitos parafuncionais observando a taxa de desgaste, fraturas e soltura das coroas provisórias. Mesmo que a literatura não apresente associação entre bruxismo e perda de implantes dentários, ainda há risco de sobrecarga nas reabilitações. O monitoramento periódico e o uso de uma placa acrílica miorrelaxante são fundamentais. Entretanto, muitas vezes, estes pacientes se afastam dos consultórios odontológicos. Normalmente, quando retornam, a situação pode ser catastrófica.

Clinical and radiographic evaluation of factors influencing the presence or absence of interproximal gingival papillae.

This study evaluated factors that may influence the presence or absence of interproximal papillae. Clinical evaluation consisted of visual determination, and quantitative analyses were made using millimeter grids on radiographs. Patients (n = 45) were divided into three groups according to age. Data were analyzed using the chi-square test followed by the Student t test (α = .05). The distance from the contact point to the bone crest had significant influence on papilla presence in both anterior and posterior sites (P < .05), whereas the width between roots of adjacent teeth did not. The papilla was missing more frequently in anterior sites. The presence of papillae was not age-dependent.

Effect of carbon and glass fiber posts on the flexural strength and modulus of elasticity of a composite resin.

The aim of this study was to evaluate the effect of prefabricated fiber posts on the flexural strength and modulus of elasticity of a composite resin. Thirty bar-shaped specimens measuring 25 x 2.0 x 2.0 mm were made, containing posts that were 1.3 mm in diameter and 20 mm long. Each group contained 10 specimens: Group 1, resin without post; Group 2, resin with carbon fiber post; Group 3, resin with glass fiber post. The samples were immersed in water at 37 degrees C until the three-point loading test was performed at a speed of 1.0 mm/minute. The results were statistically analyzed by ANOVA and Tukey's test (P = 0.05). Both fiber posts were similar in strength and both were stronger than the control. Group 3 obtained a higher mean modulus of elasticity than Groups 1 and 2, which were similar. The results of this study demonstrated that the presence of a fiber post significantly raised flexural strength values and the glass fiber post significantly increased the modulus of elasticity of the evaluated composite resin.

Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis--tension tests.

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis - tension tests

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

Influence of different cantilever extensions and glass or polyaramide reinforcement fibers on fracture strength of implant-supported temporary.

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.

Retração gengival: aspectos biológicos e protéticos / Gingival retraction: biological and prosthetics aspects

Os procedimentos para a confecção de próteses fixas necessitam de uma reprodução fiel da porção preparada e não preparada do dente, assim como do término do preparo, freqüentemente localizado no interior do sulco gengival. O comportamento biológico dos tecidos periodontais deve ser conhecido e respeitado para a manutenção da saúde e da estética gengival. Embora a retração gengival possa ser realizada de diversas formas, pouco se sabe sobre seu efeito no periodonto marginal. O objetivo deste trabalho foi realizar uma revisão da literatura sobre as técnicas e materiais existentes para afastamento do periodonto marginal, associando-as com a anatomia, função e preservação dessas estruturas biológicas.

Procedures for fixed prostheses require accurate duplication of the prepared and unprepared surfaces of the tooth, as well as the finish line, frequently placed in a subgingival position. The biological behavior of the periodontal tissues should be identified and respected for the maintenance of the health and the gingival aesthetics. Although gingival retraction has been made by different forms, few is the knowledge about their effects in the periodontal tissues. The aim of the present work is to carry out a revision of the literature about the existents techniques and materials for the gingival retraction associating them with the anatomy, the function and the preservation of those biological structures.

Influence of different catilever extensions and glass or polyamaramid reinforcement fibers on fracture strength of implant-supported temporary

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.

Influence of different cantilever extensions and glass or polyaramid reinforcement fibers on fracture strength of implant-supported temporary fixed prosthesis

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey’s test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.

Comparative histomorphometric and tomographic analysis of maxillary sinus floor augmentation in rabbits using autografts and xenografts.

Our goal was to evaluate bone neoformation promoted by a bovine xenograft composite (XC) compared with autogenous graft for maxillary sinus augmentation in a rabbit model. The left maxillary sinus of 18 male rabbits was filled with 200 mg of cortical and cancellous autogenous bone and the right sinus was filled with 200 mg of a composite comprised organic and inorganic bovine matrices, pool of bBMPs and collagen. Postoperative implant intervals of 2, 4, and 8 weeks were analyzed. Differences in the bone optical density among the groups and experimental periods were evaluated by computed tomography analysis. The tissue response was evaluated by histomorphometric analysis of the newly formed bone, connective tissue and/or granulation tissue, residual material, and bone marrow. The tomographic analyses showed a maximum optical density in the 4-week period for both groups. Histologically, an inflammatory infiltrate was observed at 2 weeks in the XC group but exclusively around the organic particles of the biomaterial. Regarding to the amount of newly formed bone, no statistical differences (p > 0.05) were observed among the two treatments throughout the implant intervals. However, by the end of the 8 weeks, the quantity of bone marrow was two times greater (p < 0.05) in the control group than in the XC group. In conclusion, the xenograft composite promotes formation of new bone in a similar fashion to autogenous bone and could therefore be considered a biomaterial with potential applications as a bone substitute in maxillary sinus floor augmentation.

Análise imunoistoquímica comparativa da periimplantite com a periodontite em humanos / Comparative immunohistochemical analysis of peri-implantitis with periodontitisin humans

As próteses implanto-suportadas são largamentes aceitas como uma opção de tratamento confiável e previsível para a reabilitação de pacientes completamente ou parcialmente desdentados. Espera-se, entretanto, que o número de pacientes sofrendo de alguma alteração dos tecidos periimplantares aumente em função do tempo de uso dos implantes osseointegráveis. Nesse estudo foram comparados microscopicamente e imunoistoquimicamente 10 casos de periodontite com 10 casos de periimplantite em humanos originados dos arquivos do Departamento de Estomatologia, Disciplina de Patologia da Faculdade de Odontologia de Bauru - USP compreendendo o período de 1963 a 2004. Foram escolhidos marcadores imunoistoquímicos para as seguintes células: NK (CD56), Pan-T (PS1), Macrófagos (KP1), Linfócitos T4 (CD4), Linfócitos T8 (CD8), Pan-B (L26); e moléculas: EGFR, E-Caderine, IgG, IgM e IgA. Análise estatística t Student (P < 0,05) revelou similaridade entre ambas lesões. A partir dos resultados encontrados pode-se concluir que a periimplantite apresenta etiopatogenia semelhante ao da periodontite, ou seja, são manifestações inflamatórias placas-associada, demonstrando a importância da motivação e instrução em hegiene bucal nos pacientes reabilitados com implantes osseointegrados como meio de prevenção e controle da saúde dos tecidos periimplantares.

Actually, implant-supported prostheses are widely accepted as a reliable treatment modality, but failures in longitudinal studies have been shown. In some cases, periimplantites with a progressive periodontal bone loss takes place, and mechanical or load factors and biological or plaque-induced lesions have been claimed as main etiologic factors. We compared ten cases of periimplantitis, with ten cases of periodontitis in order to give new findings on the peri-implant tissue breakdown. Specimens from the peri-implant and periodontal tissue were taken in ali cases for histological and immunohistochemical analysis, including the analysis of NK (C056), Pan-T (PS1), Macrophage (KP1), Lymphocyte T4 (C04), Lymphocyte T8 (C08), Pan-B (L26), EGFR, E-Caderine, IgG, IgM e IgA. It was demonstrated that both lesions harbored large inflammatory cell infiltrates. Statistics analysis demonstrated that the proportions of the various parameters studied were similar (P < O,05) in the periodontitis and in the peri-implantitis. In conclusion, we suggest that the breakdown tissue process is due to an inflammatory process similar to that observed in periodontitis. Oral hygiene instruction and plaque control evaluation, besides scaling and root planning are necessary to control these lesions.

Análise da deformação gerada em infra-estruturas de prótese fixa implantossuportada, através do uso de extensômetros / Strain-gauge analysis of the deformation of frameworks for implant-supported prosthesis

Em quaisquer estruturas sujeitas a cargas funcionais, podem ocorrer situações que produzirão sobrecargas e complicações subseqüentes. O tratamento com implantes ossointegrados implica em uma estrutura baseada em tecido biológico (osso) e componentes mecânicos (implante e restauração protética). Sobrecarga nesse sistema pode levar à perda óssea marginal e/ou falha dos componentes. Considerando que estruturas mais rígidas proporcionam melhor distribuição de carga entre os pilares de uma prótese implantossuportada, este trabalho in vitro teve por objetivos: através do uso de extensômetros, verificar a deformação gerada na infra-estrutura; observar as vantagens e desvantagens da utilização da liga cobalto-cromo, em substituição à liga de paládio-prata, na confecção de infra-estruturas para próteses sobre implantes

Avaliação das propriedades físico-mecânicas de um gesso tipo IV submetido a métodos de desinfecção. Parte II: Rugosidade superficial e estabilidade dimensional / Evaluation of the physical-mechanical properties of dental gypsum type IV submitted to disinfection methods. Part II: Surface roughness and dimensional stability

Neste estudo foram avaliados a estabilidade dimensional e a rugosidade superficial de espécimes em gesso tipo IV quando imersos em hipoclorito de sódio a 0,5 por cento e glutaraldeído alcalino a 2 por cento, ambos durante 10 minutos. A estabilidade dimensional foi mensurada por um programa de computador (Imagetools). As faces dos espécimes foram varridas e digitalizadas, e suas imagens mensuradas, enquanto a rugosidade foi registrada com o auxílio de um rugosímetro (T 1000 Hommel testing machine). Com base nos resultados dos testes físico-mecânicos realizados, e seus valores analisados estatisticamente, concluiu-se que os métodos usuais de desinfecção de modelos de gesso alteraram, por desgaste, as dimensões originais dos espécimes após a imersão nos dois desinfetantes. Esse desgaste, entretanto, não provocou uma alteração significante da rugosidade superficial

Gesso tipo IV: influência das técnicas de manipulaçäo / Type IV gypsum: influence of manipulation techniques

Analisou-se e comparou-se a resistência à traçäo diametral e à compressäo de modelos de gesso tipo IV utilizando-se diferentes técnicas de manipulaçäo. Para isto, nos grupos I e III a manipulaçäo foi mecânica e, nos grupos II e IV, manual. Nos grupos I e II mediu-se a resistência à compressäo e nos grupos III e IV, à traçäo diametral. Os resultados estatísticos (p <0,05) aplicando-se o teste de Tukey demonstraram näo haver diferença entre as técnicas para o teste de compressäo. A manipulaçäo manual influiu negativamente na traçäo diametral

Tratamento interdisciplinar I: consideraçöes clínicas e biológicas na verticalizaçäo de molares / Interdiciplinary treatment I clinical and biological consideration in molar uprighting

O presente trabalho tem por finalidade mostrar diferentes abordagens na verticalizaçäo de molares com aparelhos fixos e discutir, baseando-se em casos clínicos, o tratamento ortodôntico integrado com outras especialidades. A verticalizaçäo de molares é uma terapia ortodôntica, muito utilizada em pacientes adultos, de grande validade para os procedimentos de prótese, periodontia e implante. Importantes benefícios podem ser conseguidos durante a movimentaçäo de molares inclinados devido à perda prematura dos dentes posteriores, dos quais podemos citar: paralelismo dos dentes que serviräo de apoio à prótese fixa ou removível, obtençäo de espaço edêntulo adequado, eliminaçäo ou reduçäo de defeitos ósseos verticais sem necessidade de procedimentos cirúrgicos e melhora na proporçäo coroa-raiz em molares com envolvimento periodontal. Confeccionando-se a prótese sobre dentes verticalizados, seja ela fixa ou removível, restaura-se a funçäo normal da mastigaçäo, pois se mantém as forças oclusais direcionadas ao longo eixo dos dentes preservando dessa forma a saúde periodontal

Análise comparativa das alteraçöes dimensionais de áreas soldadas / Comparative evaluation of distortion on joints soldered by two methods

O presente trabalho buscou avaliar a alteraçäo dimensional em uma liga à base de Ni-Cr, provocada pelo processo de soldagem a arco elétrico com proteçäo de argônio (TIG), em comparaçäo com os resultados obtidos a partir da técnica convencional a maçarico. Dez juntas foram soldadas de acordo com o método correspondente para cada processo e a mensuraçäo das distorçöes causadas pelas duas técnicas de soldagem foi feita pela diferença entre o assentamento das peças antes e após a obtençäo das juntas soldadas. Entre as duas técnicas de soldagem avaliadas, a solda TIG promoveu melhor assentamento da peça soldada quando comparado aos resultados obtidos com soldagem convencional a maçarico

Destino de membrana de cortical óssea bovina colocada em posição subperióstica na calvária de cobaia / Destiny of membrane of bovine bone cortical placed in subperiostic in guinea pigs skull

Na atual pesquisa avaliamos o destino de membranas biológicas de cortical óssea bovina colocadas em posição subperióstica no crânio de cobaias machos adultos. Utilizamos um total de 12 animais, que foram divididos em 3 grupos de 4 animais. Em cada animal foi realizada a cirurgia junto a região fronto-parietal do crânio com a colocação de membrana de cortical óssea bovina sobre a superfície óssea desnuda. Os crânios de cobaias de cada grupo, foram coletados decorridos 1, 3 e 6 meses após as cirurgias. Após sofrerem descalcificação, as peças foram processadas para inclusão em Paraplast e cortes histológicos frontais semi-seiados de 6 µm de espessura, foram obtidos. A análise histológica dos cortes, mostrou que a membrana é lentamente reabsorvida da superfície óssea por atividade de células mononucleadas. Muito raramente observou-se, células multinucleadas em sua superfície. Em alguns casos, verificou-se junto das faces tegumentar e óssea da membrana, a formação de fina camada de tecido ósseo, que era em seguida reabsorvida conjuntamente com a matriz implantada

Tratamento ortodôntico em pacientes com lesöes periodontais avançadas / Orthodontic treatment in patients with advanced periodontal diseases

Pacientes que apresentam lesöes periodontais generalizadas ou localizadas säo ainda hoje motivo de preocupaçäo por parte dos ortodontistas, que muitas vezes deixam de tratá-los devido às incertezas de como esse organismo responderá às forças ortodônticas, imaginando sempre que haverá uma acentuaçäo dos problemas, agravando ainda mais o quadro clínico. No entato, quando esse tipo de tratamento é abordado de uma maneira multidisciplinar, com uma interrelaçäo do periodontista com o ortodontista, o que se tem säo resultados altamente satisfatórios tanto do ponto de vista periodontal quanto ortodôntico e principalmente satisfazendo os requisitos estéticos do paciente, melhorando sua auto estima. Este artigo tem como objetivo abordar alguns aspectos que devem ser levados em consideraçäo quando se depara com essa problemática