Effect of successive in-office bleaching sessions on microhardness, roughness, topography and flexural strength of CAD-CAM processed monolithic materials

• Grant number: 19/18759-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2019
• Effective date (End): October 31, 2020
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Renata Garcia Fonseca
• Grantee: João Fernando Carrijo Queiroz
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Some CAD-CAM monolithic materials, when exposed in the oral cavity, are susceptible to pigmentation when in contact with food coloring. Some studies indicate that bleaching may partially or totally restore the color parameters of these previously pigmented materials. However, little is known about the effect of this procedure on the surface and mechanical properties of these materials. The aim of the present study is to analyze the effect of office bleaching on microhardness, roughness, topography and flexural strength of three different materials available for CAD-CAM. In total, forty-one discs of each of the Lava Ultimate, Vita Enamic and IPS Empress CAD materials will be obtained and polished with # 600, # 1200 and # 1500 grit-blasting. All analyzes will be performed before bleaching and after the 1st session, 2nd session and 3rd session, except for flexural strength, which will occur before and after the 3rd bleaching session. The microhardness will be evaluated in a Vickers diamond-coupled microdurometer, with a load of 20 N and 20 seconds of application time, with 5 indentations per specimen performed at each moment of analysis. The roughness will be analyzed by a 3D laser confocal microscope at × 5 magnification and the Ra and Sa parameters will be recorded. The topography of the specimens at different times will be accessed by scanning electron microscopy at × 5000 and × 50 000 magnification. Biaxial flexural strength will be evaluated in a mechanical testing machine. The results will be analyzed for the assumptions of normality and homoscedasticity. If met, the microhardness and roughness data will be submitted to a mixed repeated-measures ANOVA, while the flexural strength data will be analyzed by 2-way ANOVA. If necessary, the most appropriate post test will be selected. The topography analysis will be descriptive.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

QUEIROZ, J. F. C.; FERNANDES, L.; DOVIGO, L. N.; FONSECA, R. G.. Effect of Successive In-office Bleaching Sessions on the Surface Properties, Substance Loss, Biaxial Flexural Strength, and Reliability of CAD-CAM Monolithic Materials. Operative Dentistry, v. 48, n. 1, p. 10-pg., 2023-01-01. (19/18759-0)