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This study evaluated the stress distribution on an implant-supported zirconia crown of a mandibular first molar subjected to oblique loading by occlusal contact with the natural maxillary first molar by using the 3D finite element method. Two virtual models were made to simulate the following situations: (1) occlusion between maxillary and mandibular natural first molars; (2) occlusion between zirconia implant-supported ceramic crown on a mandibular first molar and maxillary natural first molar. The models were designed virtually in a modeling program or CAD (Computer Aided Design) (Rhinoceros). An oblique load of 100 N was uniformly applied to the zirconia framework of the crown. The results were obtained by the Von Mises criterion of stress distribution. Replacement of the mandibular tooth by an implant caused a slight increase in stress on portions of the maxillary tooth roots. The crown of the maxillary model in occlusion with natural antagonist tooth showed 12% less stress when compared with the maxillary (model in occlusion with the) implant-supported crown. The mandibular crown of the implant show 35% more stress when compared with the mandibular antagonist crown on the natural tooth. The presence of the implant to replace the mandibular tooth increased the stresses on the maxillary tooth, especially in the region of the mesial and distal buccal roots.

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This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the "offset" configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann-Whitney, Kruskal-Wallis, and Dunn's multiple comparison test (α = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 ± 309.2 µÎµ) and MC (639.3 ± 278.8 µÎµ) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 ± 358.6 µÎµ) and MC (598.7 ± 357.9 µÎµ) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated.

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ABSTRACT: The present study aims to describe through a literature review, the main types of noble and non-noble alloys in dentistry looking to identify the adhesion mechanisms, compositions and mechanical properties, and its applicability as a rehabilitation resource nowadays. A bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 1971 to 2021 were collected. Laboratory studies, case reports, systematic and literature reviews, which were developed in living individuals. Articles that did not deal with metal alloys and its use in dentistry were excluded. Through the review, it was possible to ver ify that all works presented the metal alloys and their main properties, indicating that they are divided into three main types: hi gh noble alloys, noble alloys and base metal alloys differing in their levels of constituent noble metals. Several alloys and meta ls are available for the dental market each presenting advantages and disadvantages, mainly based on its specific composition.Continuous research and development are resulting in the production of new technologies and products, giving dental surgeons even more options in the design and manufacture of restorations using metal alloys and understanding that these resources will still be viable alternatives in oral rehabilitations. However, further studies on metal alloys are needed to better understand this subject.

RESUMEN: El presente trabajo tuvo como objetivo describir a través de una revisión de la literatura, los principales tipos de aleaciones nobles y no nobles utilizados en odontología buscando identificar los mecanismos de adhesión, composiciones y propiedades mecánicas, así como reflejar su aplicabilidad como recurso rehabilitador en la actualidad. Realizamos una búsqueda bibliográfica em las principales bases de datos de salud PUBMED (www.pubmed.gov) y Scholar Google (www.scholar.google.com.br), en la que se recopilaron estudios publicados desde 1971 hasta 2021. Estudios de laboratorio, informes de casos, revisiones sistemáticas y bibliográficas, que se desarrollaron en individuos vivos. Sin embargo, se excluyeron los artículos que no trataban sobre aleaciones metálicas y su uso en odontología. Se pudo observar que todos los trabajos presentaban las aleaciones metálicas y sus principales propiedades indicando que se estas dividen en tres tipos principales: aleaciones altamente nobles, aleaciones nobles y aleaciones de metales base que difierenen sus niveles de metales nobles constituyentes. Hay varias aleaciones y metales disponibles para el mercado dental, cada uno presenta ventajas y desventajas, principalmente en función de su composición específica. La investigación y el desarrollo continuo están dando como resultado la producción de nuevas tecnologías y productos, brindando a los cirujanos dentistas aún más opciones en el diseño y fabricación de las restauraciones, utilizando aleaciones metálicas y, permite concluir que estos recursos seguirán siendo alternativas viables en los tratamientos de rehabilitación. Sin embargo, se necesitan más estudios sobre el tema abordado en el trabajo, para una comprensión más profunda del tema.

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This article describes an alternative open tray technique for implant impressions using a novel reinforced silica-nylon mesh covered with acrylic resin as a splitting system in assembling the abutment complex. The purpose of the procedure is to simplify the technique and improve the resin contraction during clinical procedure, and also optimizes and reduces the chairside time for the patient. The clinical report was supported by an in vitrostudy where an analysis tool, Strain Gauge Analysis, was used to prove the clinical effectiveness of the technique. The peri-implant strain was determined on polyurethane casts with the torqued prosthesis, and statistically there was no difference in strain under torque of transfers or in the final prosthesis. The nylon mesh attached to acrylic resin represents a promising option for open tray impression technique, creating a resistant union to transfer in an excellent procedure time(AU)

Este artigo descreve uma alternativa para a técnica de moldeira aberta para moldagem de implantes utilizando uma nova malha de reforço de sílica-nylon coberta por resina acrílica para ferulização dos componentes protéticos. O propósito deste procedimento é simplificar a técnica e compensar a contração da resina durante os procedimentos clínicos, e também otimizar e reduzir o tempo de atendimento do paciente. O relato de caso foi amparado com um estudo in vitroonde uma ferramenta de análise de extensometria, Análise de Strain Gauge, foi utilizada para avaliar a efetividade clínica da técnica. A deformação peri-implantar foi determinada nas bases de poliuretano com a prótese instalada, e estatisticamente não houve diferença estatística na deformação nos torques dos transferentes ou na prótese final. A malha de nylon unida à resina acrílica representa uma opção promissora para a técnica de moldagem com moldeira aberta, criando uma união resistente aos transferentes em um excelente tempo clínico(AU)

Este estudio describe una técnica alternativa de cubeta abierta para impresiones de implantes utilizando una nueva malla de sílice-nylon cubierta con resina acrílica como un sistema de ferulización en montaje del complejo de pilares. El objetivo del procedimiento es simplificar la técnica y mejorar la contracción de la resina durante el procedimiento clínico y también optimiza y reduce el tiempo de atención al paciente. El relato clínico fue respaldado por un estudio in vitro en el que se utilizó unaherramienta de análisis, Análisis de Galgas Extensométricas, para probar la efectividad clínica de la técnica. La deformación periimplantaria se determinó en moldes de poliuretano con la prótesis apretada, y estadísticamente no hubo diferencia en la deformación del torque de los postes o en la prótesis final. La malla de nylon unida a la resina acrílica representa una opción prometedora para la técnica de impresión en cubeta abierta, creando una unión resistente para transferir en un excelente tiempo de procedimiento(AU)

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BACKGROUND: The choice between 2 or 3 implants to support a 3-unit implant-supported fixed dental prosthesis (FDP) still generates doubt in clinical practice. OBJECTIVES: The aim of this study was to evaluate stress distribution in 3-unit implant-supported FDPs according to the implant number and load direction. MATERIAL AND METHODS: A numerical simulation was performed to analyze stress and strain according to the implant number (2 or 3) and load direction (axial or oblique). A model of a jaw was created by means of the modeling software Rhinoceros, v. 5.0 SR8. External hexagon implants, micro-conical abutments and screws were also modeled. The final geometries were exported to the computer-aided engineering (CAE) software Ansys, v. 17.2, and all materials were considered homogeneous, isotropic and elastic. Different load directions were applied for each model (300 N) at the center of the prosthesis. RESULTS: The von Mises stress and strain values were obtained for the titanium structures and the bone, respectively. The implant number influenced the prosthesis biomechanics, with higher stress and strain concentrations when 2 implants were simulated. The oblique load also affected the mechanical response, showing higher stress and strain in comparison with the axial load, regardless of the implant number. CONCLUSIONS: It was concluded that for a 3-unit implant-supported FDP, a greater number of implants associated with axial loads can result in a better mechanical response during chewing.

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AIMS: The aim of the study is to evaluate the profile of peri-implant tissues in periodontally compromised patients. SETTINGS AND DESIGN: In vivo - cross sectional study design. MATERIALS AND METHODS: Fifty-eight implants were evaluated, clinically and radiographically, installed in seven individuals treated by the same team of professionals, during the years 1997 and 2005 in a private dental clinic in Vitória, ES, Brazil; that time of data collection, all implants were at least 10 years of functional loading. The variables related to the dental implants evaluated were: visible Plaque Index, Gingival Bleeding Index (GBI), probing pocket depth, bleeding on probing, and bone level, to relate them to the classification of dental implants. STATISTICAL ANALYSIS USED: The Chi-square and Kruskal-Wallis test were adopted. RESULTS: The total of 58 implants were classified: 11 (18.9%) as healthy and 12 (20.7%) as clinically stable. The other 35 implants (60.4%) had some type of peri-implant inflammation, 20 of them (34.5%) were diagnosed with peri-implant mucositis and 15 (25.9%) with peri-implantitis. Among the variables studied, the results showed statistically significant differences for implant location (P = 0.001) and GBI (P = 0.03). Most of the maxillary implants (85.7%) were classified for some type of peri-implant disease. For the implants which resulted in Score 1 for GBI, most of them (75.0%) were also classified for some type of peri-implant disease. CONCLUSIONS: Dental implants placed in periodontally compromised patients may have high long-term survival rates. However, most implants were classified with some type of peri-implant inflammation.

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OBJECTIVES: The purpose of this study was to evaluate the biomechanical behavior of the interface formed between bone and implants with machined surfaces (MS) and those modified by Al2O3 sandblasting and acid etching (SBAS). MATERIALS AND METHODS: Before surgery, topographic characterization was performed by SEM-EDX and by mean roughness measurements. Ten Albinus rabbits received randomly 20 Ti-6Al-4V implants on its right and left tibiae, with one implant placed in each tibia. After implant insertion, the implant stability quotient (ISQ) was measured by means of resonance frequency analysis (RFA). After 3 and 6 weeks, the ISQ was again measured, followed by torque removal measurements. Analysis of variance and Tukey tests were used to analyze the data. The surface of the implants removed was evaluated by SEM-EDX. Immunohistochemical analysis of osteopontin (OPN) and osteocalcin (OC) protein was performed in bone tissue. RESULTS: The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of SBAS group were statistically higher than MS. Overall, higher statistically significant ISQ values were observed in the SBAS group compared to the MS group (p = 0.012). The intra-group comparison of ISQ values in the SBAS group showed statistically significant differences between 0 and 3 weeks (p = 0.032) and 0 and 6 weeks (p = 0.003). The torque removal measurements of group SBAS were statistically higher when compared with the torque removal measurements of group MS in the time intervals of 3 weeks (p = 0.002) and 6 weeks (p < 0.001). SEM-EDX of the implant surfaces removed in SBAS group showed greater bone tissue covering and mean values atomic in percentage of Ca, P, and O statistically superior (p < 0.05) than MS group. Immunohistochemical reactions showed intense OC immunolabeling at 6 weeks postoperative for SBAS group. CONCLUSIONS: The topographical modifications made in group SBAS allowed a better mechanical interlocking between the implant and bone tissue.

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Objetivo: Bio-Oss is a xenogene bone graft in which all organic components are removed while retaining their natural mineral architecture. Therefore, the aim of this study was to evaluate, through a literature review, the benefits of using Bio-Oss for tissue regenerative treatment prior to implant placement. Materials and methods: a search was performed in Pubmed (Medline) in order to identify articles published in English between January 1, 2000 and June 31, 2018, where the Bio-Oss graft was used prior to implantation of implants in humans. A total of 40 studies were selected for detailed analysis. From this analysis, 18 articles were identified for inclusion in this review. Results: the articles analyzed in the review showed several beneficial effects of this xenograft, such as: positive osteoconductive properties, recovery of bone heights at sites with severe atrophies, slow xenograft reabsorption suggesting long term stability, survival rates and success of implants placed in grafted sites ranging from 91 to 100% in several studies. Conclusion: the use of bio-oss as a bone substitute is a viable alternative in the placement before dental implants, being used in clinical practice and with proved efficacy in several studies, due to its similarity with the bone and its high level of osteoconductivity (AU)

Objetivo: o Bio-Oss é um substituído ósseo xenógeno em que são removidos todos os componentes orgânicos, mantendo sua arquitetura natural. Assim, este trabalho teve como foco avaliar através de uma revisão de literatura os benefícios do uso do Bio-Oss para tratamento regenerativo tecidual previamente a instalação de implantes. Materiais e métodos: realizouse uma busca no Pubmed (Medline) com intuito de se identificar artigos publicados em inglês entre 1 de janeiro de 2000 e 31 de junho de 2018, em que se utilizava o enxerto Bio-Oss previamente a instalação de implantes em humanos. Foram selecionados 40 estudos completos para uma análise detalhada. A partir dessa análise foram identificados 18 artigos para inclusão nessa revisão. Resultados: os artigos analisados na revisão mostraram diversos efeitos benéficos desse xenoenxerto, como: propriedades osteocondutoras positivas, recuperação de alturas ósseas em locais com atrofias graves, reabsorção lenta do xenoenxerto sugerindo estabilidade a longo prazo, taxas de sobrevivência e sucesso de implantes colocados em locais enxertados variando de 91 a 100% em diversas pesquisas. Conclusão: a utilização do biooss como substituto ósseo é uma alternativa viável na colocação previamente ao implante dentário, sendo utilizado na prática clínica e comprovado em diversos estudos sua eficácia, devido sua similaridade com o osso natural e seu alto grau de osteocondutividade (AU)

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The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

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Abstract The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

Resumo O objetivo deste estudo foi avaliar em humanos a manutenção do volume em alvéolos frescos preenchidos por osso integral de origem bovina por meio de um estudo clínico randomizado com monocegamento. Quarenta dentes uni radiculares foram extraídos em 40 pacientes (um dente em cada participante), e apos estes pacientes foram divididos aleatoriamente em 2 grupos: indivíduos que tiveram o alvéolo fresco preenchido por osso integral de origem bovina (Grupo Biomaterial) ou por coagulo sanguíneo (Grupo Controle). Apos a exodontia os alvéolos foram medidos em suas maiores distancias mesio-distal (MD) e vestíbulo lingual/palatina (VL/P) por meio de compasso de ponta seca. O fechamento primário dos alvéolos foi realizado com um tampão fibromucoso. Apos 120 dias pós-operatórios durante o procedimento de reabertura foram obtidas novamente as maiores medidas MD e VL/P para calcular em porcentagem o nível de remodelação do osso alveolar. No grupo biomaterial observou-se uma redução em porcentagem de 1,62% e 3,29% nas medidas MD e VL/P 120 dias apos as extrações, enquanto no grupo controle houve uma redução de 4,97% e 7,18% nas medidas MD e VL/P no mesmo período. Houve diferença estatisticamente significante (p<0,05) entre os dois grupos para as medidas vestíbulo/palatina e mesiodistal na maxila. Diante dos resultados obtidos conclui-se que o osso integral de origem bovina limitou, mas não impediu a remodelação óssea alveolar.

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