Time-based characteristics of acoustic emission during dental composite restoration

Acoustic emission (AE) signals were detected and analyzed in real time during the polymerization shrinkage of composite resin restoration in an artificial dental ring with a class I cavity. Most AE hit events were observed in the initial curing period of the 1st region with high contraction rate. The range of the 2nd region for the stainless steel specimen was shorter than that for the PMMA specimen but longer than that for the human dentin specimen. AE hit events showed a blast-type signal having an amplitude in the range of 25-45 dB and a frequency band of 100-200 kHz or 240-300 kHz. These values of amplitude and frequency indicated the fracture of resin or of the adhesive layer. �� 2011 The Korean Society of Mechanical Engineers