How characterization and polishing influence, in the long term, the properties of two 3D printed resins as crowns on implants: evaluation of color, microhardness, wear resistance and durability.

• Grant number: 23/15861-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: December 31, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Ricardo Faria Ribeiro
• Grantee: Fernanda Deodato Severo Nascimento de Jesus
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The objective of this study is to evaluate the wear, color change, microhardness, survival of resin crowns for long-lasting 3D printing, made with surface characterization or just finishing, on implants with different prosthetic connections that share the same abutment model, evaluating , also, the loss of torque caused after thermomechanical cycling. Test specimens simulating lower first molars will be obtained through scans of the prosthetic abutments. The antagonist will be made with the same material, with the anatomy of upper first molars. Wear and survival tests will be carried out on a Chewing Mechanical Fatigue Testing Machine. The antagonists will be attached to the vertical rods of the machine, while the embedded implants will be positioned at the base of the test container and 300,000 cycles will be carried out, with a frequency of 1.0 Hz and a load of 20 N. The specimens made on the implants will be evaluated for survival throughout the test. To evaluate the color, the samples will be evaluated using a Delta Vista 450G spectrophotometer with a fitting base made to standardize color readings. To determine the hardness of the sample, a microhardness meter will be used with a Knoop-type pyramidal diamond indenter with a load of 25g applied for 10 seconds. The torque loss of the prosthetic screw will be calculated after evaluating the untorque and thermomechanical cycling from the initial torque values (T0). The implants will have their crowns disconnected after scanning and the distortion (T1) will be evaluated. The data will be tabulated and analyzed according to the distribution and homoscedasticity of the results.