Impact of gastric acid on the mechanical strength of glass-ceramics for CAD/CAM after different surface treatments glaze versus mechanical polishing

• Grant number: 21/05141-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2021
• Effective date (End): August 31, 2022
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Aldiéris Alves Pesqueira
• Grantee: Gabriel Nunes Sampaio
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Recently, the causes and effects of acid erosion caused by gastric acid on ceramic restorations have become a topic of great interest in dentistry. This study aimed to evaluate the mechanical behavior of two glass ceramics for CAD/CAM, a feldspar glass-ceramic (FC) (CEREC Blocs) and another synthetic glass-ceramic based on lithium disilicate (LS) (IPS e.max CAD), after different surface treatments (Glaze versus mechanical polishing (extra and intraoral/periodic polishing) - Ceramisté kit - Shofu), submitted to the erosive challenge (EC-immersion in hydrochloric acid (HCl 5%) simulating gastric juice), through the analysis of flexural strength (r) and flexural modulus (FM), then 180 specimens of each tested ceramic with dimensions of 14 × 4 × 1.2 will be manufactured. The specimens will be divided into 2 groups according to the surface treatment (G-glaze or mechanical polishing which will be subdivided into MP - mechanical polishing and CP - clinical polishing/repolishing. Half of each group (n = 10) will be subjected to the erosive challenge (EC) for 91 (EC1), 182 (EC2), and 273 hours (EC3). The other half will be stored for 24 h in distilled water (C - control group) and throughout the experiment 91 (C1), 182 (C2), and 273 hours (C3). The r and FM analyzes will be performed after the periods of C and EC. The groups that will receive clinical repolishing (CP) will be analyzed after EC2 (repolished after EC1), EC3 (repolished after EC1 and EC2), C2 (repolished after C1), and C3 (repolished after C1 and C2). The data obtained in each analysis will be submitted to the normality test and later to the most appropriate statistical test, with a significance level of 5%. (AU)