Light-activated composite materials are used in many biomaterial applications, but most commonly as dental restoratives. Due to limited light penetration and high polymerization shrinkage, these restorations must be built up in increments to ensure both adequate physical properties (i.e., degree of conversion and hardness) and strong adhesion at the tooth interface. We hypothesize that a curing model that predicts the physical properties of light-activated composites in realistic dental geometries can be made and validated. Such a curing model would require (1) knowing the optical properties of the composite, (2) predicting the light dose (irradiance W time) in the composite, and (3) relating the delivered light dose to the cured composite's physical properties. We hypothesize that the composite's optical properties change during curing and that the composite's physical properties can be predicted using a threshold light dose for 80% curing. We expect that a validated curing model will improve understanding of how composite formulation affects curing and provide crucial information about the curing process at the composite-tooth interface. ? ? To test our hypotheses, we will produce experimental composites with known and varied ller types, sizes and compositions, monomer formulations, and with two different photosensitizers. Optical properties of cured and uncured composites will be measured and quantified as a function of light dose. The physical properties of composites cured at different irradiances and times will be measured and correlated with light dose to determine the 80% curing threshold. The optical property measurements and thresholds will be used in a dynamic Monte Carlo light transport model to predict physical properties. These predicted values will be validated by comparison with dental cavity preparations that have been restored with photo-cured composites. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21DE016758-01A2
Application #
7387686
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Drummond, James
Project Start
2008-07-01
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
1
Fiscal Year
2008
Total Cost
$224,531
Indirect Cost
Name
Providence St. Vincent Medical Center
Department
Type
DUNS #
038035002
City
Portland
State
OR
Country
United States
Zip Code
97225
Prahl, Scott A; Dayton, Amanda; Juedes, Kyle et al. (2012) Experimental validation of phase using Nomarski microscopy with an extended Fried algorithm. J Opt Soc Am A Opt Image Sci Vis 29:2104-9
Ramella-Roman, Jessica C; Nayak, Amritha; Prahl, Scott A (2011) Spectroscopic sensitive polarimeter for biomedical applications. J Biomed Opt 16:047001
Duncan, Donald D; Fischer, David G; Dayton, Amanda et al. (2011) Quantitative Carré differential interference contrast microscopy to assess phase and amplitude. J Opt Soc Am A Opt Image Sci Vis 28:1297-306
Prahl, Scott A; Fischer, David G; Duncan, Donald D (2009) Monte Carlo Green's function formalism for the propagation of partially coherent light. J Opt Soc Am A Opt Image Sci Vis 26:1533-43