Effects of Bis-GMA/TEGDMA Vinyl Conversion Levels on Cellular Response:
A Combinatorial Approach
Nancy J. Lin,1 LeeAnn O. Bailey,1 Newell Washburn2
1Biomaterials Group, Polymers Division, National Institute of Standards and Technology, Gaithersburg , MD
2Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA
Composite materials for dental restorations do not attain complete vinyl conversion after curing. To study the cellular response to incomplete conversion, techniques were developed to fabricate dental resins with varying conversion levels. Common resin components, 2,2-bis[p-(2’-hydroxy-3’-methacryloxypropoxy)phenyl]propane (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA), were used for these studies.
Two types of conversion gradients were prepared using a visible light curing unit, and the resulting conversion profiles were determined using near infrared spectroscopy. Centered, overlaid fabrication, which involves placing a mask over the sample and centering the sample on the stage, resulted in resins (55 mm x 12 mm x 1.5 mm) with a peak conversion in the middle of the sample (27.5 mm) and a minimum conversion on both edges (0 and 55 mm). Off-centered fabrication resulted in resins with a minimum conversion at one edge (0 mm) and a maximum conversion at the opposite edge (55 mm). The final conversion range for each sample depended upon the mask design, cure time, and sample placement.
Macrophages, which play a significant role in inflammation, were selected to evaluate the cellular response. Resins were sterilized and preconditioned with growth media, and cells were seeded directly onto the resins. After 24 h, cell viability was evaluated. Viability decreased as the resin conversion level decreased. Cell spreading and attachment were also reduced at lower vinyl conversion levels. Studies to quantify the inflammatory response as a function of resin conversion are ongoing.
Name: Nancy J. Lin
Mentor: Francis Wang
Division: Polymers Division (854)
Laboratory: Materials Science and Engineering Laboratory (MSEL)
Location: Room A105, Bldg 224, MS 8543
Phone: (301) 975-4935
Fax: (301) 975-4977
Sigma Xi: Not a member