Resin Viscosity and Light Intensity Determine Validity of Exposure Reciprocity Law in Photocuring of Composites

Sri Vikram Palagummi, National Institute of Standards and Technology

Abstract:Exposure reciprocity law suggests that, if the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve a similar photo-polymerized composites. A NIST-developed cantilever beam-based instrument coupled with a high-speed data acquisition NIR spectrometer was used to test the validity of this law for a range of model dental composites by simultaneously measuring the degree of conversion, polymerization stress (at various instrumental compliances), and temperature change in real time.