Effect of light curing units in the physical properties of experimental resin cements with different photo-initiators systens

• Grant number: 11/08277-6
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2011
• End date: September 30, 2013
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: William Cunha Brandt
• Grantee: William Cunha Brandt
• Host Institution: Universidade de Santo Amaro (UNISA). São Paulo , SP, Brazil
• City of the host institution: São Paulo

Abstract

The objective of the study will be to analyze the spectrum of different light curing units (LCUs) and photo-initiators systems and the influence in the physical properties of resin cements containing different photo-initiators systems when activated through a ceramic facet by halogenic light and LED LCUs. Experimental resin cements containing a mixture of BisGMA and TEGDMA and 60% in mass of filler particules silanezed, it will be prepared with the use of the photo-initiators CQ (Camphorquinone), PPD (Phenyl Propanodione) and BAPO (Oxido bis-alquil fosfínico). The co-initiators used will be the tertiary amine DMAEMA (dimethylaminoethyl methacrylate ) and DPIHFP (diphenyliodonium hexafluorphosphate). The LCUs used will be a halogenic lamp (XL 2500-3M/ESPE) and two - LED (FreeLigth 2-3M/ESPE and Bluephase (Ivoclar Vivadent). The IPS Emax-press ceramic (Ivoclar Vivadent) with 1,0 mm of thickness it will be used for the tests. The measure of the irradiance of the LCUs and the emitted in certain wavelengths will be accomplished through power meter and spectrometer (USB 2000), respectively. These verifications will be accomplished with and without the ceramic facet. The curve of absorption of the photo-initiators will be checked by an espectrometer (Varian Cary 5G). Samples with 7,0x2,0x1,0 mm (LengthxWidthxHeight) they will be made and FTIR spectroscopy analysis it will be used for evaluation of the Degree of Conversion of the cements. After, these same samples will be submitted to the mini-flexural strength test and flexural modulus in a universal testing machine (EMIC). After, a part of the fractured sample will be used for reading of the Knoop hardness (Shimadzu). The results obtained in all the tests will be submitted to the variance analysis two factors. All of the analyses will be submitted to the Tukey´s test (5%). (AU)