RESUMO
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 (Pâ<0.05) among the brands evaluated. On the other hand, square screws showed higher resistance to torsion than hexagonal screws; regardless the commercial brand.
Assuntos
Retenção em Prótese Dentária/instrumentação , Desenho de Prótese , Falha de Prótese , Coroas , Dente Suporte , Implantes Dentários para Um Único Dente , Prótese Dentária Fixada por Implante , Análise do Estresse Dentário , Humanos , TorqueRESUMO
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).
