Research and Education
Influence of an iodonium salt on the properties of dual-polymerizing self-adhesive resin cements

Presented at the 30th Brazilian Society of Dental Research, Águas de Lindóia, SP, Brazil, September 2013.
https://doi.org/10.1016/j.prosdent.2016.10.013Get rights and content

Abstract

Statement of problem

Dual-polymerizing self-adhesive resin cements present mechanical properties that may adversely affect the clinical performance of luted fiber-reinforced posts.

Purpose

The purpose of this in vitro study was to evaluate the properties of dual-polymerizing self-adhesive resin cements after the addition of an onium salt.

Material and methods

The experimental groups were set according to the molar concentration of diphenyliodonium hexafluorphosphate (DPIHFP) (0.5, 1, and 2 mol%). The resin cements were submitted to a push-out bond strength test and assessed for flexural strength (ISO 4049/2009), degree of conversion (Fourier-transformed infrared spectroscopy), depth of polymerization, swelling coefficient, and degradation in solvent. The data were statistically analyzed by ANOVA, Tukey test, Kruskal-Wallis test, Dunn multiple comparison, and paired Student t test (α=.05).

Results

All the RelyX U100 groups with onium salt showed the highest degree of conversion after 24 hours and 7 days (P<.001). However, no statistical difference was found among the BisCem groups (P=.054). The addition of 0.5 mol% DPIHFP increased the push-out bond strength and microhardness of RelyX U100 and promoted less degradation after immersion in solvent. The BisCem control group did not present a statistical difference from the experimental groups in terms of bond strength; the control group and the 0.5 mol% group showed no degradation in solvent. For swelling coefficient and flexural strength, no difference was found between the BisCem groups (P=.067 and P=.173), and the RelyX U100 2 mol% group presented the lower value (P<.001 and P=.048). Depth of polymerization was not statistically different in the experimental groups for either resin cement (P=.999).

Conclusions

The addition of 0.5 mol% DPIHFP improved the physical properties of dual-polymerizing self-adhesive resin cements.

Section snippets

Material and Methods

The dual-polymerizing self-adhesive resin cements used in this study were RelyX U100 (3M ESPE) and BisCem (Bisco Inc). The compositions of the materials are presented in Table 1. DPIHFP (Aldrich Chemical Co) was used without further processing. A light-emitting diode unit (Radii Cal; SDI Ltd) with an output intensity of 1200 mW/cm2 was used for activation, and the output intensity was measured with a radiometer. The experimental groups were set according to the molar concentration of DPIHFP

Results

Push-out bond strength results are presented in Figures 1 and 2. For RelyX U100, the control group showed the lowest mean bond strength ±standard deviation at 4.8 ±2.3 MPa, and the group with 0.5 and 1 mol% presented the highest at 8.5 ±3.5 and 6.7 ±3.8 MPa, respectively. Adhesive cement/dentin failure was the most observed mode in all groups, but adhesive cement/post failure was also detected. For BisCem, the 0.5 mol% group showed a higher bond strength (7.4 ±3.2 MPa) than the 1 mol% group

Discussion

The incorporation of DPIHFP in dual-polymerizing self-adhesive resin cements improved the degree of conversion and push-out bond strength and decreased the polymer degradation in the solvent and the swelling coefficient of the materials tested. The increased reactivity of these cements with the addition of DPIHFP is related to the low bond energy of the carbon–iodine bond (26 to 27 kcal/mol), which facilitates the decomposition of the excited iodonium compound to an anion, an aryl radical, and

Conclusions

The addition of 0.5 mol% DPIHFP improved the physical properties of dual-polymerized self-adhesive resin cements, increasing the degree of conversion, push-out bond strength, and microhardness.

References (39)

Cited by (9)

  • Improved mechanical performance of self-adhesive resin cement filled with hybrid nanofibers-embedded with niobium pentoxide

    2019, Dental Materials
    Citation Excerpt :

    However, a correlation has been shown between obtaining the spectra immediately after mixing the pastes and obtaining them separately [53]. In the present study, to consider a dual-cure condition, the analysis began immediately after mixing both pastes [18,41,54], inserted over the crystal and light-activated 3 min after mixing the pastes, by a single and calibrated operator. According to some studies, dual-cure cements take up 6 min to photo activate because this delay has been shown to improve their mechanical properties, stimulating the chemical activation of the material [55,56].

  • Effects of thermal cycling on bonding properties of novel low-shrinkage resin adhesive

    2023, Hua Xi Kou Qiang Yi Xue Za Zhi / West China Journal of Stomatology
View all citing articles on Scopus

Supported by grants from the Brazilian government through FAPEAM (Foundation for Amazonas State Research).

View full text