Effect of repair strategies upon the Y-TZP and composite resin bonding

• Grant number: 09/50889-9
• Support Opportunities: Regular Research Grants
• Duration: June 01, 2009 - May 31, 2010
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Luiz Felipe Valandro
• Grantee: Luiz Felipe Valandro
• Host Institution: Faculdade de Odontologia (FOSJC). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The aim of this study will be to evaluate the effect of different repair strategies and the use of MDP-based cement liner upon the shear bond strength beetween Y-TZP (ytrium cation-doped tetragonal zirconia polycrystals) and composite resin. A hundred Y-TZP blocks (5 X 5 X 2 mm) (In Ceram 2000 YZ cubes, Vita Zahnfabrik, Germany) will be embedded in acrylic resin and the free surface will be polished with a sequence of sandpapers (#400,600 and 1200) and separated by chance in ten groups (n=10). The repair strategies will include surface treatment with Cojet system (COJ), with a MDP-primer/activator system (MDPS), with alumina sandblasting (JAT), with Metal/Zirconia primer (MZR), and with alcohol cleaning (CRTL), and they will be followed or not by the application of a MDP-based cement liner (Panavia F,Kuraray, Japan) (pan), which will result in the following groups: COJpan, COJ_, MDPSpan, MDPS_, JATpan, JAL, MZRpan, MZR_, CRTLpan, CRTL_. After the application of the tested treatments, composite resin (Clearfil Majesty Esthetic, Kuraray, Japan) will be applied to the ceramic surface, using the central cylindrical hole (diameter = 3,0mm) of a aluminum split-mold. After light-curing, the groups will be stored in distilled water at 37° C for 60 days and, within this period, 12,000 thermal cycles between 5 and 55° C will be applied. Following the storage period, the shear bond strength test will be performed in a universal testing machine E-MIC DL-1000 (EMIC, São José dos Pinhais, PR, Brazil), in which the load (50KgF) will be applied in a crosshead speed of 1, 0 mm/ min. The results will be submitted to the analysis of variance and post-hoc test, according to their distribution of frequencies. (AU)