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Title: 0587 - Effect of Monowave and Polywave LCUs on Adhesion to Zirconia

Authors:

Yake Wang (Presenter)
Wuhan University

Yaning Chen, Wuhan University
Cui Huang, Wuhan University

Abstract:

Objectives: Light activation is an essential procedure in zirconia adhesion since it has been proven to have great influence on the mechanical properties and bonding strength of resin cements. This study aimed to evaluate the effect of monowave and polywave LED units on the adhesion of dual-cured self-adhesive resin cements to monolithic zirconia.

Methods: Two kinds of LCUs (Elipar S10, monowave, emitting spectrum 430-480nm from 3M ESPE and Bluephase Style, polywave, emitting spectrum 385-515nm from Ivoclar Vivadent) were selected. Dual-cured self-adhesive resin cements (RelyX U200 from 3M ESPE and SpeedCEM from Ivoclar Vivadent) were adhered to zirconia disks with the help of Teflon molds before being light-cured from the other side of disks. µSBS test was conducted after 24h ddH2O storage (24h) and after 10,000 thermal cycles (10k/TC). Failure modes were examined by stereomicroscope and SEM. The degree of conversion was measured by a FTIR spectrometer with an ATR accessory.Statistical analyses were performed using software and statistical significance was preset at α = 0.05.

Results: For µSBS values, there were significant differences among all groups (F=10.368, p<0.001) in 24h and 10k/TC aging level. There was no significant difference in immediate DC of the resin cement when cured by different LCUs. For 24h DC values, BS-U200 were significantly higher than ES-U200 and BS-SC were higher than ES-SC with no significant difference. BS-SC group possesses relatively high bonding strength in both 24h and 10k/TC aging levels, and the highest 24h DC. It can be assumed that in this group, the emission spectra of the LCU matches the absorption spectra of the cement. The incompatibility between the available wavelength of resin cements and LCUs may result in unsatisfactory transmission and transformation of light energy.

Conclusions: Within the limitation of this study, the emission spectra of LED units can significantly influence the adhesion of dual-cure self-adhesive resin cements to zirconia in both immediate and artificial aging levels. It should be noted that the LCUs shall offer light energy that matches the absorption wavelengths of photoinitiators in resin cements, otherwise the mechanical properties and bonding strengths may be compromised.

This abstract is based on research that was funded entirely or partially by an outside source:
National Natural Science Foundation of China under grant NO.81500889.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE

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