Effect of photoinitiator type and concentration on degree of conversion and cross-link density of experimental composites

• Grant number: 10/15103-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2011
• End date: December 31, 2011
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Roberta Caroline Bruschi Alonso
• Grantee: Stephanie Lauren Lisboa de Andrade
• Host Institution: Coordenadoria de Pesquisa. Universidade Bandeirantes (UNIBAN). São Paulo , SP, Brazil

Abstract

The aim of this study will be to evaluate the effect of photoinitiator system composition and concentration on polymerization characteristics of experimental resin composites, in order to establish formulations with improved physical and mechanical properties. In this way, degree of conversion and cross-link density tests will be conducted. Composites based on BisGMA/TEGDMA and 65% of BaAlSi/SiO2 filler will be prepared with different type and concentration of photoinitiators (Canphorquinone - CQ, Phenil Propadione - PPD e association - CQ/PPD, at 1 e 2%). Ten circular specimens (7 mm diameter x 1 mm thick) of each material will be prepared. These specimens will be used for both tests. Degree of conversion will be determined by Fourier Transformed Infrared Spectroscopy (FTIR). Cross-link density will be indirectly evaluated by Knoop hardness measurements before and after storage in absolute-ethanol for 24h. Data will be submitted to appropriate statistical tests at 5% significance. Additionally, a possible correlation between degree of conversion and cross-link density will be determined. (AU)