ABSTRACT: 1789
Kinetic Follow-up of the Two Radical Species in Dental Resins
| J. LEPRINCE1, J. DEVAUX2, and G. LELOUP1, 1Universite Catholique de Louvain, Bruxelles, Belgium, 2Universite Catholique de Louvain, Louvain-la-Neuve, Belgium | |||||||||||||||
Objective: To study the influence of illumination parameters on the kinetic decay of the two types of trapped free radicals present in dental resins: allylic- and propagating ones. Methods: The resin formulation was the following: Bis-GMA (64wt%) and TEGDMA (36wt%) with camphorquinone and tertiary amine (0,5:0,5wt%). The illumination parameters, i.e. energy density (ED, mJ/cm2), power density (PD, mW/cm2) and time (t, s), were modulated with a halogen light (Optilux 501) coupled with a rheostat as follows:
Results: Trapped-radicals kinetics of decay can be divided in two different phases. In the first one (0 to 24h), while curves of all modes decrease with the same slope, different concentrations of radicals are underlined. On one hand, samples cured at higher EDs exhibit more trapped radicals. On the other hand, at a same ED, radical concentrations are higher for a lower PD, thus for a longer irradiation time. In the second phase, all decay curves seem to tend to 0 after about 100 days. As to compare the behaviour of the two radical types, propagating species decrease quicker than allylic ones during the first few hours. Conclusion: ED, irradiation time and PD affect differently the trapped free radicals concentrations, and the two different radical types behave differently during the first few hours.
| |||||||||||||||
| Seq #187 - Polymerization Processes 2:00 PM-3:15 PM, Friday, July 4, 2008 Metro Toronto Convention Centre Exhibit Hall D-E | |||||||||||||||
|
Back to the Dental Materials 5: Polymer-based Materials - Chemistry and Composition Program | |||||||||||||||
©Copyright 2008 American Association for Dental Research. All Rights Reserved.