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Proceedings Paper

Characterization of dental composite curing kinetics using dynamic light scattering
Author(s): Elaine M. Wells-Gray; Sean J. Kirkpatrick; Ron L. Sakaguchi
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Paper Abstract

Polymer resin composites are a class of widely used restorative dental materials that undergo a complex polymerization curing process that has been the subject of substantial research. This study uses speckle correlation methods based on dynamic light scattering as a tool to monitor the rate and extent of dental composite polymerization during and after photo-curing. Thin disc-shaped samples (<2mm) were constructed using composite consisting of 50:50 BisGMA/TEGDMA resin, quartz silica filler particles, and camphorquinone as photo-initiator. A 633 nm HeNe laser beam was used to probe the top surface of the sample via a backscattered speckle pattern, while the bottom surface was illuminated with a halogen curing lamp (peak wavelength=470nm) to initiate the polymerization reaction. The speckle patterns were recorded with a CCD camera, and stored as a 'speckle cube' for post processing. Correlation values of the intensity fluctuation were calculated on a pixel-by-pixel basis for pairs of subsequent speckle images and then ensemble averaged. Results show a sharp decrease in correlation at the onset of curing, indicating a large amount of double bond conversion and movement within the composite. Correlation values then quickly increase, eventually reaching a plateau near unity, indicating cessation of molecular rearrangement. The kinetic behavior demonstrated by our correlation curves are in good agreement with curing data found in the literature, and demonstrate the usefulness of this technique for monitoring dental composite curing.

Paper Details

Date Published: 25 February 2009
PDF: 7 pages
Proc. SPIE 7176, Dynamics and Fluctuations in Biomedical Photonics VI, 717605 (25 February 2009); doi: 10.1117/12.808045
Show Author Affiliations
Elaine M. Wells-Gray, Oregon Health & Science Univ. (United States)
Sean J. Kirkpatrick, Oregon Health & Science Univ. (United States)
Ron L. Sakaguchi, Oregon Health & Science Univ. (United States)

Published in SPIE Proceedings Vol. 7176:
Dynamics and Fluctuations in Biomedical Photonics VI
Valery Viktorovich Tuchin; Lihong V. Wang; Donald D. Duncan, Editor(s)

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