Modification in the composition of dental resins: evaluation of addition of chitosan and bisalcylphosphine oxide in the properties and biocompatibility

• Grant number: 13/15771-2
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2014
• End date: April 30, 2016
• 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

Abstract

Methacrylates Monomers (MM) used in several areas of dentistry can damage the body's cells, such as human gingival fibroblasts (HGF). These MM may penetrate the oral cavity due to their incomplete polymerization reaction and / or degradation of polymers used in dentistry. Because of this, the MM can induce problems in the body as changes in DNA, câncer and cell death. Therefore, the protection of these effects caused by MM is very important. Some studies have shown that chitosan molecule (CTS) can promote a protective action against the cytotoxic and genotoxic effects induced by MM. In addition, some studies have shown that the alternative photoinitiator Bisalcylphosphine oxide (BAPO) compared to the photoinitiator commonly used in dental composites camphorquinone (CQ), can enhance the reactivity of MM-based polymers, therefore decreasing their cytotoxic effects . Thus, the aim of the study is to evaluate the properties such as degree of conversion (DC), flexural strength (FS), flexural modulus (FM) and Knoop hardness (KH) and the biological effects of cytotoxic and genotoxic resins containing CTS and BAPO in its composition. Resins containing BisGMA and TEGDMA are prepared. To this mixture is incorporated photoinitiator system, which is a group containing a photoinitiator system standard CQ (Group C), and a group containing alternative photoinitiator system BAPO (Group B). To this mixture, different concentrations of CTS are added. The combinations used are: CC Control CQ (CQ with and without CTS), CC05 (with CQ and 0.5 wt% CTS) CC1 (with 1 wt% CQ and CTS), CC2 (with CQ and 2wt% of CTS ), CB Control BAPO (BAPO with and without QTS) CB05 (with BAPO and 0.5 wt% CTS), CB1 (BAPO with CTS and 1 wt%), CB2 (with BAPO and 2wt% CTS). The polymerization is conducted for 20 s with a LED light curing (Bluephase-Ivoclar). The GC will be measured in FTIR (Spectrum100). FS and FM will be tested in a universal testing machine (EMIC-DL500) and KH in microhardness (Shimadzu). Samples from each group with or without polymerization will be used to test for cytotoxicity SulforodaminaB (SRB) and genotoxicity assays for micronuclei. The averages of each analysis will be submitted to analysis of variance and appropriate post hoc test. (AU)