Knoop Hardness of dental resin with chitosan and bisalcylphosphine oxide

• Grant number: 13/21646-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2014
• Effective date (End): December 31, 2014
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: William Cunha Brandt
• Grantee: Brisa Cila Camargo Pereira
• Host Institution: Universidade de Santo Amaro (UNISA). São Paulo , SP, Brazil

Abstract

Monomers of Methacrylates (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 Knoop hardness (KH) of the 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 KH will be in a microhardness (Shimadzu) and the averages of each analysis will be submitted to analysis of variance and appropriate post hoc test.