Influence of different photoinitiated systems for chemical and physical properties of experimental simplified adhesives systems

Author(s)

Diogo Dressano

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2015-02-27

Examining board members

Adriano Fonseca de Lima; William Cunha Brandt; Flavio Henrique Baggio Aguiar

• Advisor: Giselle Maria Marchi; Adriano Fonseca de Lima

Abstract

The aim of this study was to evaluate the influence of different initiators (camphorquinone-CQ and fenilpropanodiona - PPD), and a cationic polymerization accelerator (hexafluorophosphate diphenyliodonium - DPI), in the chemical and mechanical properties of experimental adhesives. The experimental adhesives were formulated using 25% of bisphenol A diglycidildimethacrylate ( Bis-GMA ), 20% of triethylene glycol dimethacrylate ( TEGDMA), 10% of 1, 3 - Glycerol dimethacrylate ( GDMA ), 25% of 2- Hydroxyethyl methacrylate ( HEMA ), 2 mol% of dimethylaminoethyl amine benzoate (EDAB) and 20% etanol. The groups were divided according to the initiator system (CQ, PPD or CQ/PPD), varying the concentration (0.5 or 1 mol%), and the amount of DPI (0; 0.5 or 1 mol%). Each combination of initiators was combined to the the salt¿s concentration, totalling 24 experimental groups. The experimental resins were evaluated for water sorption (SR) and solubility (SL) (n = 5); cohesive strength (RC) by microtensile teste (EMIC DL 2000) (n = 10); flexural modulus and the strength (n = 10) by three-point bending test (Kratos 2000RK, Kratos, São Paulo, Brasil) (0.6mm thick, 1.5mm wide and 12mm long); and degree of conversion (DC) (n = 5), using a Fourier Transform near infrared spectroscopy (FT-FIRS, Vertex 70, Bruker Optics, Ettlingen, Alemanha). For all tests, the specimens were irradiated with a light emitting diode (LED) of 3rd generation (VALO, Ultradent Products Inc; S. Jordan, UT, USA), a uniform energy dose of 28J / cm2. Statistical analysis for all evaluations, was performed by the Tukey test at 5% significance level. For the GC analysis of variance was used two criteria, as for the other tests we used analysis of variance one criterion. The addition of a cationic salt influenced positively the conversion value, and most of the properties evaluated. Despite the lowest conversion, the polymers containing CQ+PPD presented better properties than the resins containing CQ only. It could be concluded that the DPI improved the conversion of the experimental resins, ensuring the best values on the chemical and mechanical properties assessed. The PPD when taken in conjunction with the CQ, even with low degree of conversion, improves the properties of the polymer. The union of CQ and PPD photoinitiators in the concentration of 0,5mol%, plus the use of 1 mol% of DFI, provided experimental systems with superior properties (AU)

• FAPESP's process: 13/09989-5 - Influence of different photo-initiators and polymerization accelerators in the chemical and mechanical properties of experimental adhesive systems
• Grantee: Diogo Dressano
• Support Opportunities: Scholarships in Brazil - Master