Study of bond strength, failure probability and reliability of cementing interfaces

• Ano de defesa: 2022
• Autor(a) principal: Monteiro, Raphaelle Santos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Adesão; Adhesion; Cementation; Cerâmica; Ceramics; Cimentação; Dental Materials; Dental Prosthesis; Materiais Dentários; Prótese Dentária
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25146/tde-01092022-105323/

Associating the correct selection of dental ceramics and the adhesive cementation protocol, as well as obtaining a reliable union at the ceramic/cement, cement/dental substrate interfaces, is essential for the longevity of indirect restorations. This work analyzed the microshear bond strength of ceramic and dental substrates to the Multilink® Speed self-adhesive and self-curing resin cement (Ivoclar Vivadent, Schaan, Liechtenstein), as well as the failure probability, Weibull modulus and characteristic strength of these interfaces through Weibull statistical analysis. For that, 20 (twenty) slices of each ceramic and dental material, as follows: 1) LD Lithium disilicate (IPS e.max CAD®); 2) ZLS - Zirconia reinforced lithium silicate - (Celtra Duo®); 3) Y-TZP C - Yttria-stabilized polycrystalline tetragonal zirconia in Conventional color (IPS ZirCAD MO®); 4) Y-TZP T - Translucent color yttria-stabilized polycrystalline tetragonal zirconia (IPS ZirCAD MT®); 5) E + E - Enamel Etched; 6) E unetched Enamel and 7) D Dentin. The ceramics had dimensions of 2 mm thickness and the teeth were obtained from human third molars, all specimens were prepared and included in PVC tubes with acrylic resin, followed by polishing. The self-adhesive resin cement was inserted inside the plastic matrix on each surface unit of these 7 types of substrates, resulting in a cylinder with a diameter of 1.40 mm and a height of 1 mm, following the manufacturer\'s recommendations. The specimens were stored in deionized water at 37°C for 24 h, each specimen was subjected to the microshear bond strength test. The mechanical assay data were submitted to statistical analysis using the Kruskal-Wallis and Dunn tests. Qualitative failure analysis was performed using a stereomicroscope (and AxioCam MRc, ZEISS®) and classified as adhesive, cohesive and mixed, with a representative specimen of each failure submitted to a scanning electron microscope (SEM). Weibull statistical analysis was performed to obtain the following metrics: probability of failure, Weibull modulus (m) (reliability) and characteristic strength (0). In general, the E + E group had higher bond strength, lower probability of failure, higher reliability, and higher characteristic resistance among all the evaluated groups, containing significant similarity to the ZLS and LD groups and a statistically significant difference to the other dental substrates (E and D), containing the median minor dentin among all substrates examined. Among the ceramics, the highest values of bond strength and characteristic strength were obtained, after E + E, in ZLS (Celtra Duo) which presented high data variability, the LD group (e-max) presented greater reliability among the ceramics. analyzed ceramics. The adhesive failure mode was predominant among the failure types. With this, it is concluded that the adhesive interface of glass ceramics presented higher characteristic strength, lower probability of failure and greater reliability, being similar to selectively etched enamel.