Polymerization shrinkage of polymeric dental composites characterized by X-ray microcomputed tomography

POLY 634

Sheng Lin-Gibson, slgibson@nist.gov and Jirun Sun. Polymers Division, NIST, 100 Bureau Drive, Stop 8543, Gaithersburg, MD 20899
The main objective of this study was to assess the feasibility of using X-ray microcomputed tomography (μCT) as a viable technique for accurate measurements of composite volumetric changes due to polymerization. μCT, a non-destructive 3D imaging technique that measures the intensity of content at each voxel, was used to determine the volume of polymeric dental composites before and after photopolymerization. The matrix resin for the composites consisted of various mass ratios of 2,2-bis(4-(2-hydroxy-3-methacryloxypropoxy)-phenyl]propane (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) and the fillers were barium boroaluminosilicate glass and fumed amorphous silica. Polymerization shrinkage obtained by μCT agreed well with shrinkage values obtained via density measurements for the same sample. μCT enables the characterization of polymerization shrinkage under clinically relevant conditions. In particular, the sample geometry, and the physical state (liquid or solid) are flexible.