Effect of different crystaline fractions on the biaxial flexural strength of a CAD-type lithium disilicate glass ceramic

• Grant number: 18/16295-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2018
• End date: September 30, 2019
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Ligia Antunes Pereira Pinelli
• Grantee: Artur Toshiharu Hirai Olivi
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Nowadays, high crystalline content ceramics such as lithium disilicate (LS2) have been shown to be an excellent choice of material for the manufacture of indirect aesthetic restorations, since they are able to combine esthetics with good mechanical properties. Considering the good qualities of LS2, the Laboratory of Vitreous Materials (LaMaV) of the Federal University of São Carlos developed a CAD-type LS2 (milling), in which Vickers hardness (6.0 GPa), translucency (contrast ratio 0.28 at 700 nm) and toxicity (non-cytotoxic) had already been studied, however, other properties still need to be evaluated. Thus, the aim of this study will be to evaluate the influence of different crystalline fractions on the biaxial flexural strength (RF) of the LaMaV CAD. The crystalline fractions will be obtained by different heat treatments of nucleation (TT): TT1- 1h30 at 500oC, TT2- 3h at 500oC, TT3-6h at 500oC and TT4-6h at 480oC. It will be made 75 discs with 12 mm diameter by 1.2 mm thickness, 15 of them of IPS e-max CAD (control). For the RF test, a three-ball ball piston device coupled to the EMIC test machine (10 KN, 0.5 mm / s) according to ISO 6872: 2008 shall be used. The data will be submitted to statistical analysis adopting a level of significance of 5%.