A influência do tratamento de superfície na resistência de união à cerâmica de zircônia (Y-TZP): uma atualização

Abstract

Y-TZP ceramics with their high density characteristics and less than 1% glass matrix in their composition, present low bond strength to dental tissues. This limitation of use requires surface treatments prior to cementing the material in the mouth. Although several studies have investigated the surface treatments to Y-TZP, there is still no fixed protocol to treat it in order to confer an adequate bond strength. This review aimed to evaluate the different surface treatment techniques among which mechanical, chemical and association for Y-TZP ceramics, in addition, demonstrate the best use of each pre-treatment to obtain a stable union between ceramics-cement. A search was made in the Pubmed database using the descriptors "yttria stabilized tetragonal zirconia" AND "surface treatment" where, at first, 100 studies were rescued. After applying the inclusion and exclusion criteria, 22 articles were selected to produce this review. The various surface treatments performed in Zirconia over time are divided into mechanical (APA blasting, Rocatec, Siljet and Cojet systems and lasers) and chemical (SIE conditioning, HF solutions and MDP bonding agents - primers and silanes). APA increased surface free energy and provided better wettability and adhesion of the cement material to Y- TZP, but favored weakening and the possibility of fractures. The Rocatec, Siljet and Cojet systems, in general, favored the enrichment of silica to the ceramic surface by blasting alumina particles modified by silica, which resulted in a ceramic layer with greater micromechanical retention. The lasers have not shown a satisfactory improvement in bond strength to Y-TZP when compared to other systems. The SIE method showed satisfactory results in terms of bond strength and the fact that it does not cause fracture propagation on the ceramic surface. HF solutions, in turn, did not show good clinical adhesion or good bond strength when compared to other pretreatments. The primers and silanes, on their turn, did not confer good bond strength. The studies also pointed out that there is no fixed clinical protocol to treat the ceramic surface of Y-TZP, however, there are some recommendations that can be performed in each pre- treatment technique in order to obtain a better long-term bond strength.