Dentistry applications of fiber Bragg gratings: irradiation protocols for bulk fill flow dental composites

This study evaluates the polymerization shrinkage of a bulk fill flow composite photoactivated by continuous or ramped irradiation. Sample teeth were prepared with Class I occlusal cavity. The fiber Bragg grating sensors are placed along bucco-lingual and mesio-distal directions for measuring the shrinkage and temperature. The results reveal that ramp irradiation protocol showed a slower evolution of shrinkage polymerization curve, but the final values of shrinkage for continuous and ramp protocols are not significantly different. The ramp irradiation protocol showed higher temperature changes than that of the continuous irradiation procedure.