Effect of bleaching and polishing on the recovery and susceptibility to changes of the optical properties and on the surface parameters of CAD-CAM monolithic materials previously stained in coffee

• Grant number: 21/04476-6
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2022
• End date: September 30, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Renata Garcia Fonseca
• Grantee: Renata Garcia Fonseca
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Monolithic CAD-CAM restorations may undergo changes in their optical properties when in contact with coloring solutions. In an attempt to reverse this condition, avoiding the replacement of these restorations, the bleaching, polishing with abrasive pastes and tips and alternatively air-polishing with abrasive powders would be the possible options. No studies were found that compared the efficacy of these procedures on optical properties and their effects on the surface parameters of these materials. The purpose of the present study is to evaluate the effect of bleaching and different polishing modalities on the recovery and susceptibility to changes of the optical properties of CAD-CAM monolithic materials previously stained in coffee. Additionally, analyze the roughness, topography, hardness and change in mass resulting from these treatments. For the analysis of optical properties, specimens of each of the materials LavaTM Ultimate, VITA ENAMIC®, IPS Empress® CAD, IPS e.max® CAD and VITA® Suprinity will be allocated in 6 groups depending on the treatment used to remove the stain resulting from the previous immersion in coffee (n = 12 / group) as follows: 1) no treatment (control), 2) polishing with prophylactic paste Proxyt; 3) polishing with silicone tips of Ceramisté system; 4) bleaching with carbamide peroxide 10% 6 h day for 7 days; 5) bleaching with hydrogen peroxide 35% - 1 application of 45 min and 6) air-polishing with Clinpro Prophy Powder. A spectrophotometer will be used to record the color coordinates L*, a*, b* at baseline (C0), after immersion in coffee and subsequent treatment described above (C1) and after a new immersion in coffee (C2). For the analysis of recovery and susceptibility to changes of the optical properties, differences in luminosity (”L), color (”E00), translucency (”TP00) and whiteness (”WID) will be calculated between C1C0 and C2C0. Additionally, ”E00, ”TP00 and ”WID will be interpreted based on their respective thresholds of 50: 50% perceptibility and 50: 50% acceptability. The analyzes of two-dimensional and three-dimensional roughness (n=12/group) and hardness (n=12/group) will be carried out before (R0/D0) and after (R1/D1) the treatments, respectively in rugosimeter, 3D laser scanning confocal microscope, and Vickers diamond indenter. The analysis of the change in mass (n=12/group) will be performed before (M0) and after (M1) the treatments, in an analytical balance. The analysis of the surface topography (n=1/group) will be performed for each treatment in SEM-FEG. With the exception of this analysis, which will be qualitative, the data resulting from the other analyzes will be treated statistically by the most appropriate tests for each situation (± = 0.05). (AU)