Influence of adhesive protocol on physicochemical properties and ceramic bond strength of experimental resin cements containing ternary photoinitiator system

Author(s)

Alan Rodrigo Muniz Palialol

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2017-02-23

Examining board members

Giselle Maria Marchi; Rafael Pino Vitti; William Cunha Brandt; Vanessa Cavalli; Luís Roberto Marcondes Martins

• Advisor: Giselle Maria Marchi

Abstract

The present study evaluated the influence of an adhesive protocol on physicochemical properties and ceramic bond strength (BS) of experimental resin cements (ERCs) containing a ternary photoinitiator system. For this purpose, five ERCs were prepared using a Bis-GMA/TEGDMA (1:1 molar ratio) base compound. The photoinitiator system was composed by 1 mol% of camphorquinone, 2 mol% of dimethylaminoethil methacrylate and different diphenyliodonium hexafluorophosphate (DPI) salt different concentrations of 0, 0.25, 0.5, 1 or 2 mol%, resulting in five ERCs. As an inhibitor, 0.1mol% of hydroxyl butyl toluene was used and a 60% in weigth of silanated barium-aluminum-silicate glass for fillers particles. Thus, ten groups were established so that one half was performed without adhesive mixture (G1-G5) and the other half (G6-G10) with adhesive mixture of 3 ?l of Adper Scotchbond Multi-Purpose ¿ Bond. For all laboratory tests, the light curing was performed through an IPS e.max ceramic block with Bluephase G2 light source at 1265.5 mW/cm2 for 60 seconds. Seventy IPS e.max Press ceramic specimens (10 mm x 10 mm x 3 mm) were fabricated and randomly divided among the ten groups previously established. The specimens were fixed to light curing composite resin Filtek Z250 blocks (10 mm x 10 mm x 5 mm). After storage for 24 hours at 37oC, the specimens were sectioned perpendicular to the bond interface (25 to 30 beams per block) and half of the beams of each block were submitted to immediate microtensile bond strength test. The other half was separated for the microtensile test after storage in distilled water for one year. The failure mode was analyzed by a stereomicroscope (Leica MZ75) at 40x magnification. Additionally, it was evaluated the ultimate tensile strength (UTS) of ERCs using hourglass shape specimens (n=10). Degree of conversion (DC) and real-time polymerization kinetics were measured in disc shape specimens (n=5) using near-infrared spectroscopy (NIRS). Water up take and solubility (WS) were assessed too using disc shape specimens (n=5). Data were analyzed using analysis of variance (repeated measures for BS test and two criteria for the other tests) and Tukey test at a significance level of 5%. For immediate and after water storage BS values, there was no statistical difference between groups (p0,05). Similarly, there was no statistical difference between immediate and after one year of water storage (p0,05). The 0 mol% DPI ERC showed the higher values of WS and the lower values for DC, maximum rate of polymerization and UTS (p0,05). The others ERCs presented similar values and were not statistically different from each other (p0,05). The addition of adhesive led to higher DC values only for 0 mol% DPI ERC (p0,05). The addition of DPI salt improve the reactivity and physicochemical properties of ERCs. The adhesive had no influence on the physicochemical properties of ERCs containing DPI salt. Addition of a DPI salt to light-activated ERCs increased its DC, but was not able to increase the BS between the ceramic and resin materials. For this study, one year of water storage was not capable of jeopardizing ceramic BS (AU)

• FAPESP's process: 14/02898-7 - Microtensile bond strength to a glass ceramic and properties of experimental resin cements containing a diphenyliodonium derived salt
• Grantee: Alan Rodrigo Muniz Palialol
• Support Opportunities: Scholarships in Brazil - Doctorate