Assessment of interfacial defects at composite restorations by swept source optical coherence tomography

ABSTRACT. In clinical dental practice, it is often difficult or even impossible to detect and assess interfacial adhesive defects at adhesive restorations by means of visual inspection or other established diagnostic methods. However, nondestructive optical coherence tomography (OCT) may provide a better picture in this diagnostic scenario. The aim of this study was to evaluate the suitability of swept source OCT (SS-OCT) for the nondestructive assessment of interfacial deficiencies at composite restorations and the evaluation of cohesive defects within composite material. Ten class V composite restorations that were not adhesively luted were taken as validation objects and examined for frequency of interfacial gaps, air entrapments, and defects between composite layers using SS-OCT with a 1325-nm center wavelength. Light microscopy was used to inspect for inherent structures. SS-OCT detected 79.5%±1.8% of the total gap lengths at the enamel interface and 70.9%±0.4% at the dentin interface. Additionally, defective structures in composite restorations were displayed. It was shown that OCT imaging has the potential to nondestructively assess the interfacial adaptation of composite restorations and to detect internal defects in the layered composite material.