Influence of Two Types of Connections in Driver-Retention Screw Assembly.

Rehabilitation with implant-supported prostheses has reached high success rates. However, mechanical failures are still reported, mainly in retention screws of abutments in single implant-supported crowns; which is designed to be the weakest structure and the first component to fail under overloading. In this sense, the aim of this in vitro study was to evaluate the influence of different joint designs (square or hexagonal) on resistance to deformation of driver-retention screw assembly of 3 commercial brands (Neodent, Singular, and Sin). A total of 42 retention screws from 3 commercial brands were used. The samples were divided into 2 joint groups, square (SQU) and hexagonal (HEX), and separated by commercial brands. Several components (implants and abutments) with standard platform (4.1 mm in diameter) were used. The resistance to deformation of the driver-retention screw assembly was measured using an accurate digital torque wrench for all commercial brands (Neodent [NEO], Singular [SGL], and Sin [SIN]) and joint designs (square or hexagonal). It was found no statistically significant difference (P <0.05) among the brands evaluated. On the other hand, square screws showed higher resistance to torsion than hexagonal screws; regardless the commercial brand.

Interfacial Properties and Bottom/Top Hardness Ratio Produced by Bulk Fill Composites in Dentin Cavities.

The aim of this study was to evaluate the bond strength, bottom/top hardness ratio, marginal adaptation, and interfacial nanoleakage of regular viscosity bulk fill composites (RVBFC) and regular viscosity traditional composites (RVTC). Two RVBFC (Filtek Bulk Fill and Aura Bulk Fill) and two RVTC (Filtek Z250XT and Aura) were assessed. Forty conical cavities (4.8×2.8×4.0) were prepared in bovine dentin and restored with composites (n=10). After 24h in water, marginal adaptation was evaluated by staining with a caries detector. The top and bottom surfaces of the conical restorations were stained for five seconds and the gap percentage in the composite/dentin interface was determined using digital images on a measurement program (ImageTool). The Vickers microhardness was measured and the bottom/top microhardness ratio (B/T) was determined. Push-out bond strength test was performed in a universal testing machine (0.5mm/min) and failure modes were evaluated in a stereomicroscope (20×). Other specimens (n=3) were produced for interfacial nanoleakage evaluation. Data were analyzed using one and two-way ANOVA and Tukey's test (α=0.05). The gap percentage was higher in the bottom compared to the top. The B/T ratio of the Aura Bulk Fill was statistically lower than other composites. Push-out bond strength were similar among composites. The RVBFC presented lower nanoleakage than the RVTC in the bottom of the conical restoration and there was no difference among the materials in the top surfaces. In conclusion, Filtek Bulk Fill performed better than Aura Bulk Fill regarding the analyzed properties.

Interfacial properties and bottom/top hardness ratio produced by bulk fill composites in dentin cavities

Abstract The aim of this study was to evaluate the bond strength, bottom/top hardness ratio, marginal adaptation, and interfacial nanoleakage of regular viscosity bulk fill composites (RVBFC) and regular viscosity traditional composites (RVTC). Two RVBFC (Filtek Bulk Fill and Aura Bulk Fill) and two RVTC (Filtek Z250XT and Aura) were assessed. Forty conical cavities (4.8×2.8×4.0) were prepared in bovine dentin and restored with composites (n=10). After 24h in water, marginal adaptation was evaluated by staining with a caries detector. The top and bottom surfaces of the conical restorations were stained for five seconds and the gap percentage in the composite/dentin interface was determined using digital images on a measurement program (ImageTool). The Vickers microhardness was measured and the bottom/top microhardness ratio (B/T) was determined. Push-out bond strength test was performed in a universal testing machine (0.5mm/min) and failure modes were evaluated in a stereomicroscope (20×). Other specimens (n=3) were produced for interfacial nanoleakage evaluation. Data were analyzed using one and two-way ANOVA and Tukey's test (α=0.05). The gap percentage was higher in the bottom compared to the top. The B/T ratio of the Aura Bulk Fill was statistically lower than other composites. Push-out bond strength were similar among composites. The RVBFC presented lower nanoleakage than the RVTC in the bottom of the conical restoration and there was no difference among the materials in the top surfaces. In conclusion, Filtek Bulk Fill performed better than Aura Bulk Fill regarding the analyzed properties.

Resumo O objetivo deste estudo foi avaliar a resistência de união, razão base/topo de microdureza, adaptação marginal e nanoinfiltração interfacial de resinas compostas bulk fill (BF) e tradicional (RT) de viscosidade regular.: Duas BF (Filtek Bulk Fill e Aura Bulk Fill) e duas RT (Filtek Z250XT e Aura) foram testados. Quarenta cavidades cônicas (4,8×2,8×4,0) foram preparadas em dentina bovina e restauradas com os compósitos (n=10). Depois de 24 h em água, a adaptação marginal foi avaliada por meio do corante com detector de cárie. As faces de topo e base das restaurações cônicas foram coradas por cinco segundos e a porcentagem de fendas na interface compósito/dentina foi determinada utilizando-se imagens analisadas num programa (ImageTool). A microdureza Vickers foi mensurada e a razção base/topo de microdureza (B/T) foi determinada. A resistência de união por push-out foi executada numa máquina de ensaios universal (0,5mm/min) e o padrão de fratura avaliado num estereomicroscópio (20x). Espécimes adicionais (n=3) foram confeccionados para avaliação da nanoinfiltração interfacial. Os dados foram analisados por meio de ANOVA a dois fatores e teste de Tukey (a=0,05). A porcentagem de fendas foi maior na base que no topo. A B/T da Aura Bulk Fill foi estatisticamente menor que os demais compósitos. A resistência de união por push-out foi similar entre os compósitos. As BF apresentaram menos nanoinfiltração que as RT na base das restaurações cônicas e não houve diferenças entre os materiais no topo. Conclui-se que a Filtek Bulk Fill comportou-se melhor que a Aura Bulk Fill considerando-se as propriedades analisadas.

Influência do tipo de conexão (quadrado ou hexagonal) na resistência a deformação do conjunto chave-parafuso de retenção de prótese sobre o implante / Influence of joint design (square or hexagonal) on resistance to deformation of driver-screw retention assembly on implant-supported prosthesis

O tratamento reabilitador com próteses implantossuportadas tem alcançado elevados índices de sucesso. No entanto, falhas mecânicas ainda podem ocorrer, especialmente, nos parafusos de retenção dos pilares protéticos de restaurações unitárias sobre implante, sendo esses desenhados para ser o elo mais fraco na estrutura e ser o primeiro elemento a falhar em situações de sobrecarga. Nesse contexto, o objetivo deste trabalho foi avaliar in vitro a influência de diferentes tipos de conexões (quadrado ou hexagonal) na resistência à deformação do conjunto chave-parafuso de retenção de três diferentes marcas comercias (Neodent, Singular e Sin). Foram utilizados quarenta e dois (42) parafusos de retenção, de três (3) diferentes marcas comerciais. Esses foram divididos em dois grandes grupos de conexão, quadrada (QUA) e hexagonal (HEX) e separados por marcas comerciais. Foram utilizados vários componentes (implantes e pilares protéticos) que apresentavam plataforma regular padrão (4.1 mm de diâmetro). Para medir a força da resistência à deformação do conjunto chave- -parafuso de retenção, utilizou-se um torquímetro digital de alta precisão, para cada uma das três (3) diferentes marcas comerciais - Neodent (NEO), Singular (SGL) e Sin (SIN) - variando a geometria do sistema de conexão (quadrado ou hexagonal). Observou-se ausência de diferença estatisticamente significante (p<0,05) entre as três marcas comerciais analisadas. Por outro lado, independente da marca comercial, dentre os parafusos examinados, os parafusos quadrados apresentaram maior resistência à torção do que os parafusos hexagonais (AU).

Rehabilitation with implant-supported prostheses has reached high success rates. However, mechanical failures may still occur mainly in retention screws of abutments in single implant-supported crowns, which are designed to be the weakest structure and the first component to fail under overloading. In this context, the aim of this in vitro study was to evaluate the influence of different joint designs (square or hexagonal) on resistance to deformation of driver-screw retention assembly of three commercial brands (Neodent, Singular and Sin). A total of forty-two retention screws from three commercial brands were used. The samples were divided into two joint groups, square (SQU) and hexagonal (HEX) and separated by commercial brands. Several components (implants and abutments) with standard regular platform (4.1 mm diameter) were used. The resistance to deformation of the driver-retention screw assembly was measured using an accurate digital torque wrench for all commercial brands - Neodent (NEO), Singular (SGL) and Sin (SIN) - varying the joint designs (square or hexagonal). No statistically significant difference (p<0.05) among the brands evaluated was found. On the other hand, square screws showed higher resistance to torsion than hexagonal screws regardless the commercial brand (AU).

Pesquisa estatística sobre os tipos de conexões implante/componentes protéticos mais utilizados no Brasil / Statistical survey of types of connections implant/prosthetic component most used in the Brazil

Atualmente encontra-se disponível no mercado de Implantodontia uma grande variedade de desenhos de implante e de componentes protéticos, propiciando os mais diversos tipos de designs de restauração sobre implante. O objetivo deste trabalho foi avaliar o design da restauração (plataforma regular ou reduzida) e o tipo de conexão do implante (hexágono externo, hexágono interno e cone morse) preferencialmente usados no Brasil e os motivos que justificaram essa escolha pelos profissionais. Para isso, foram entrevistados 216 profissionais durante o 31º Congresso Internacional de Odontologia de São Paulo (CIOSP), realizado no ano de 2013. A maioria dos entrevistados foi do gênero masculino (67,7%), especialistas (59,2%) e com até cinco anos de graduado (25,0%). Observou-se que a maioria dos profissionais entrevistados utiliza hexágono externo (52,8%), seguido por hexágono interno (22,2%), cone morse (24,0%) e replace select (0,9%). Em relação aodesignda interface pilar implante, observou-se que a maioria prefere plataforma regular (58,4%) em relação à plataforma reduzida (41,6%). Concluiu-se que a maioria dos profissionais que atua na área de Implantodontia no Brasil opta pela utilização de restaurações sobre implante com hexágono externo e plataforma regular principalmente devido à conveniência de uso...

It is currently available in the Implantology market a wide variety of implant designs and abutments, providing many types of designs for implant-supported restorations. The aim of this study was to evaluate the restoration design (regular or reduced platform) and the type of implant connection (external hexagon, internal hexagon, and morse-tape connection) preferably used in Brazil and the reasons for that choice. For this, 216 professionals were interviewed during the 31st International Dental Congress of São Paulo (CIOSP), in 2013. The respondents were mostly men (67.7%), specialists in Implantology (59.2%), and up to five years of graduation (25%). Among the types of the implant connections selected, most of respondents used external hexagon (52.8%), followed by internal hexagon (22.2%), morse-tape connection (24.0%), replace select system (0.9%). Regarding the design of implant-abutment interface, it was observed that most of the respondents used regular platform (58.4%), followed by reduced platform (41.6%). It was concluded that most of the professionals working with dental implants in Brazil prefer external hexagon and regular platform due convenience of use...