Comparison between mechanical polishing and surface sealant, associated or not with the application of low temperature plasma, on the degradation of ceramics with resin matrix for CAD/CAM system: structural, mechanical, optical and biological analysis

Abstract

This project will be divided into 2 studies that will have as general objective to evaluate the structural, mechanical, biological (Study 1) and optical (Study 2) characteristics of 03 resin-matrix ceramics for CAD/CAM, a resin nanoceramics (Cerasmart - GC), a glass ceramic in a resin interpenetrating matrix (VITA Enamic - VITA) and other zirconia-silica ceramic in a resin interpenetrating matrix (Shofu Block HC - SHOFU), after different polishing protocols (Ceramisté polishing kit (Shofu) or surface sealant (Palaseal - kulzer) associated or not with PECVD film deposition (plasma-enhanced chemical vapor deposition), after different in vitro aging procedures (T-Thermocycling or EC-Erosive Challenge and/or (I-immersion in acid/dye solutions (IDW - distilled water, , IBT - black tea and IRW-red wine). 728 specimens of each ceramic will be made, being made three different sizes to fit in their respective analyses. The specimens will be divided into groups according to the surface treatment and aging they will undergo. The polishes performed will be: 1) Mechanical Polishing (MP) - that the mechanical polishing will be carried out with the Ceramisté kit (SHOFU, Kyoto, Japan); 2) Palaseal surface sealant (SP) - a thin layer of Palaseal sealant will be applied (Heraeus Kulzer); 3) Mechanical Polishing (MP) + PECVD film deposition (Mp+ PECVD) - after MP, the surfaces of specimens in this group will be treated by deposition of PECVD films (plasma-enhanced chemical vapor deposition) and 4) Palaseal surface sealant (SP) + film deposition by PECVD (SP+ PECDVD). The in vitro aging procedures will be: 1) Erosive Challenge (EC): immersion in HCl 5% (pH= 2,0) for 273 hours; 2) Thermocycling (T): to 30,000 thermocycling cycles varying the temperature between 5 and 55oC for 30 seconds and 3) Immersion in dye solution (I): immersion in three solutions - distilled water (IDW), black tea (IBT) and red wine (IRW) for 36 days. The response variables of the study 1 will be: analysis surface roughness (Ra), contact angle and surface free energy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Atomic force microscopy (AFM), mechanical analysis (Vickers hardness (HV), Flexural strength (r), modulus of elasticity (ME)) and biological analysis: quantification of cultivable cells (CFUs), total biomass quantification (CV) and biofilm structure analysis (SEM). The study 2 will be optical analysis (color change (”E00, ”L, ”C, ”H), translucency (TP) and contrast (CR)). The data obtained will be submitted to the test of adherence to the normal curve, appropriate statistical test being applied to compare mean values of the samples. (AU)