Repair of defective composite restorations instead of full replacement has been actualised over the last decades.
The degree of conversion (DC) is a measurement of the curing of a resin-based material. Fourier Transform Infrared spectroscopy (FTIR) may be used to determine the DC. The method calculates the conversion of reactive methacrylate groups in the material. The calculation is based on ratios of area or height of specific peaks in the FTIR spectrum of the material.