Influence of alternative photoinitiators on bond durability, marginal adaptation and physical-chemical properties of experimental adhesive resins photocured by LEDs

Author(s)

Eduardo José Carvalho de Souza Júnior

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2014-08-14

Examining board members

Mário Alexandre Coelho Sinhoreti; Andre Luiz Fraga Briso; Ricardo Danil Guiraldo; Lourenço Correr Sobrinho; Adriano Fonseca de Lima

• Advisor: Mário Alexandre Coelho Sinhoreti

Abstract

The aim of this study was to evaluate the effect of light emitting diodes (LEDs) on the physical-chemical properties, bond strength (BS) and marginal adaptation (MA) of experimental adhesives containing diferent photo-initiators. A model resin containing a mixture of BisGMA/HEMA (60/40 wt%) and DMAEMA (co-iniciator) was prepared using different photo-initiators: CQ (Camphorquinone), PPD (1-Phenyl-1,2-Propanedione) e BAPO (Bisalquylphosphine oxide) and their association. The specimens were photoactivated by two LEDs, one monowave (Radii Cal, SDI) and other polywave (Bluephase G2, Ivoclar Vivadent). Irradiance was measured in potenciometer and the energy dose was standardized. The following properties were analyzed: degree of conversion (DC) and for the curing kinetics (CI), dentin permeability (DPM), water sorption (SO), water solubility (SL), flexural strength (FS), flexural modulus (FM) and yellowing (YL). For the BS test, the microtensile test was realized in 70 molars with planned dentin, immediately or after 1-year of water storage. The MA, superficial and internal marginal adaptation measurements were realized by epoxy replicas of the bonded margins using the scanning eléctron microscopy. DC, DPM, SO, SL, FS, FM and AM were submitted to a two-way ANOVA and BS to a two-way repeated measurement ANOVA. Next, the analyzes were submitted to the Tukey¿s test ('alfa' = 5%). The adhesives containing the alternative photoinitiators, such as BAPO and BAPO/amine showed a higher curing potential, promoted by the curing kinetics. Moreover, these alternative photoinitiators showed a better dentin sealing, with similar sorption and solubility values and high physical-mechanical properties when compared to the other groups based in CQ. In relation to the bond strength, the BAPO containing adhesives promoted higher performance even after 1-year of hydrolytic degradation (AU)

• FAPESP's process: 10/19483-3 - Influence of alternative photoinitiators on bond durability, marginal adaptation and phisical-chemical-mechanical properties of experimental dental adhesives photoactivated by LED
• Grantee: Eduardo José Carvalho de Souza Junior
• Support Opportunities: Scholarships in Brazil - Doctorate