EFFECT OF THE ACID CHALLENGE ON THE TOPOGRAPHY OF SURFACE, STAIN AND RESISTANCE TO MICRO SHEARING OF A PRINTING RESIN NANOHYBRID TO RESINOUS CEMENT

• Grant number: 22/12933-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2022
• End date: October 31, 2023
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Marco Antonio Bottino
• Grantee: Victoria da Silva Chahin
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The aim of this study is to evaluate the effect of the acid challenge on the surface topography, staining and microshear strength of a nanohybrid printing resin to resin cement. For this, 38 blocks (7x7x2 mm) of resin for nanohybrid 3D printing will be made, with the aid of a 3D LCD printer, cleaned in isopropyl alcohol for 4 minutes, light cured for 60 minutes in a light curing unit. For the evaluation of bond strength, 20 blocks will be randomly divided between the factors "erosive challenge (with and without erosive challenge)" and "surface treatment (with and without silicatization). The blocks will be embedded with chemically activated acrylic resin in PVC pipes. For the silicate groups, blasting will be carried out with silica coated aluminum oxide particles (20s, 2.5 bar). For groups without silicatization, this step will be waived. For the microshear test, 6 resin cement cylinders (Ø = 0.8 mm and h = 2 mm) will be made on the surface of 5 blocks of each group and, with the exception of the control group, these specimens will be subjected to an acid challenge by through laboratory cycling (0.1% citric acid solution, 30 minutes, under orbital shaking at 60 rpm). The microshear test will be performed in a testing machine, with the aid of a stainless steel wire (Ø = 0.25 mm), at a speed of 0.7 mm/min until the specimen fails. The tested specimens will be evaluated in an optical stereomicroscope (20X) to classify the failure modes. Representative faults will be analyzed in SEM (50X and 80X). Nanohybrid printed resin blocks (n=3) for the groups with and without acid challenge will be submitted to evaluate the surface roughness with a rugosimeter. To evaluate staining, impression resin blocks (n=6) for the groups with and without acid challenge will be subjected to daily immersions of 10 minutes for 30 days in coffee solutions and the registration of the color will be carried out at 7, 14, 21 and 30 days with a spectrophotometer. The bond strength data will be submitted to 2-factor ANOVA and Tukey 5%. Roughness data will be submitted to 1-factor ANOVA and Tukey 5%. The data obtained for the failure and staining modes will undergo qualitative descriptive analyses.