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Effect of the gastric juice associated to toothbrushing on the long-term physical and mechanical properties of CAD/CAM monolithic materials

Grant number: 19/00460-8
Support type:Regular Research Grants
Duration: August 01, 2019 - July 31, 2021
Field of knowledge:Health Sciences - Dentistry
Principal Investigator:Renata Garcia Fonseca
Grantee:Renata Garcia Fonseca
Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
Assoc. researchers:Lívia Nordi Dovigo


The advancement of monolithic materials available in blocks for CAD/CAM has stimulated the investigation of the most varied aspects facing different challenges. However, to date, little is known about how these materials behave when exposed to gastric juice, a fact that is frequent in patients with gastroesophageal reflux and bulimia nervosa. The purpose of this study was to evaluate the effects of the gastric juice associated to tootthbrushing on the roughness and hardness of CAD/CAM monolithic materials, up to 5 years under simulated clinical function, and on their topography, color stability and flexural strength after 5 years under simulated clinical function. The materials evaluated will be Lava Ultimate (3M ESPE), Vita Enamic (Vita Zahnfabrik), IPS Empress CAD (Ivoclar Vivadent), IPS e-max CAD (Ivoclar Vivadent) and Vita Suprinity (Vita Zahnfabrik). Discs (10 mm × 1.2 mm) will be obtained and allocated in two groups according to the following exposures: 1) intercalation between artificial saliva and toothbrushing (control); 2) intercalation between simulated gastric juice and toothbrushing, simulating 1, 2, 3, 4 and 5 years of clinical function. The roughness (Sa) (n=15), topography (n=2) and Vickers hardness (n=10) will be analyzed respectively in confocal microscopy, scanning electron microscope (SEM) and microdurometer, before exposure (L0) and after each year of simulated clinical function, resulting in L1, L2, L3, L4 and L5 readings. For the color stability (n=20), in spectrophotometer, one reading will be performed before exposure (L0) and, at the end of the 5th year of simulated clinical function, the specimens will be stained in deionized water, coffee or diet cola for a period corresponding to 5 years and then a second reading (L1) will be performed. The biaxial flexural strength (n=30) will be evaluated in a mechanical test machine at the end of the 5th year of simulated clinical function. In addition, the Weibull analysis will be performed to determine the reliability of the materials. The results will be submitted to statistical analysis based on previous analyzes of normality and homoscedasticity. (AU)