Effect of isolating thermal cycling factors on degradation of dental materials and adhesive interface

• Grant number: 16/08672-6
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2016
• End date: November 30, 2018
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Rubens Nisie Tango
• Grantee: Rubens Nisie Tango
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The long-term success of dental restorations is limited by their durability in oral environment. In vitro tests remain as an essential tool for primary evaluation of dental materials. Thermal cycling is one of the most widely used test to simulate physiological aging, in which biomaterials are submitted to in oral environment. The aim of this study is to determine the effect of thermal cycling, in non-aqueous medium on the degradation of dental materials (feldspar ceramic and resin cement) and adhesive interface (composite resin and bovine dentin with two different adhesives) comparing different artificial aging method: water storage in distilled water, thermal cycling in water and thermal cycling in mineral oil followed by flexural test and microtensile test. CAD-CAM feldspar ceramic blocks will be cut and polished to obtain 90 bars (14 X 4 X 1.2 mm). Ninety bars of resin cement will be made (12 x 2 x 2 mm) according to manufacturer´s instructions. For microtensile test, resin-dentin blocks will be obtained with two different adhesives (etch-and-rinse and self-etching). The bars and blocks will be randomized (n = 10 for bars and n = 5 for blocks) e will be aged by thermal cycling in water and mineral oil for 500 (ISO 11405), 5000, 10000 cycles for 30 s at 5o C e 55o C and water storage at 37o C for the same time of thermal cycling (9h, 4 days and 8 days), totalizing 36 groups. After aging procedures, flexure and microtensile test will be performed and data will be submitted to statistical analysis. Microhardness and elastic modulus measurements will be performed in all groups. The fractured samples will be analyzed by SEM and FTIR. (AU)