J Adhes Dent 21 (2019), No. 3 7. June 2019
J Adhes Dent 21 (2019), No. 3 (07.06.2019)
Page 281-286, doi:10.3290/j.jad.a42549, PubMed:31165107
Bond Strength of Methacrylate-based Blends Containing Elastomeric Monomers and Alternative Initiators after Thermomechanical Cycling
Ely, Caroline / Ottoboni, Thiago Dias / Kumagai, Rose Yakushijin / Souza, Natália Alves de / Ramos, Tatiana da Silva / Arrais, César Augusto Galvão / Piva, Evandro / Reis, André Figueiredo
Purpose: To evaluate the bond strength to dentin produced by experimental adhesives formulated with an elastomeric methacrylate monomer (EMM) and an alternative initiator system based on a Thioxanthone derivative (QTX).
Materials and Methods: A self-etching primer was used. For the bonding resin, a model adhesive (G1) was formulated containing bis-GMA/TEG-DMA/HEMA (co-monomeric blend) + CQ/EDAB (initiator system). The other groups were formulated by adding to this formulation: EMM only (G2), QTX (G3), or EMM and QTX (G4). Clearfil SE Bond was used as the commercial control group. Fifty bovine teeth (n = 5) were restored with each one of the five adhesives. After restorative procedures, half of the specimens were stored in distilled water at 37°C for 24 h. The other half was fixed on a metal stub and subjected to 200,000 mechanical (50 N loading at 2 Hz frequency) and 1000 thermal cycles (5°C and 55°C). Afterwards, specimens were serially sectioned into beams and tested in tension until fracture. Bond strengths were statistically analyzed by two-way ANOVA and Tukey's test (α = 5%).
Results: After 24 h, significantly higher µTBS was observed for the formulation containing EMM and QTX (G4) when compared to Clearfil SE Bond (p < 0.05). No significant differences in µTBS were detected among the experimental groups after 24 h (p>0.05). After thermomechanical cycling, no significant differences were observed among groups.
Conclusion: The addition of EMM and QTX can be considered as possible alternative in dental adhesive formulations.
Keywords: adhesives, microtensile bond strength, thermomechanical load cycling, thioxanthone