Qualitative and Quantitative Analysis of Bulk-Fill Composite Resin Restorations Using Optical Coherence Tomography

The optical coherence tomography (OCT) allows the imaging of soft and hard tissues at real time with high resolution. Although studies that use OCT to evaluate marginal defects of dental restorations are reported, there are no studies that evaluate the microstructural defects of bulk-fill composite resins. Here, it is proposed a methodology for qualitative and quantitative analysis of bulk fill composite resins restorations using OCT. Thirty human molar teeth with class II cavities were randomly assigned to 6 experimental groups to be restored with six different bulk-fill composite resins. All restorations were scanned with an OCT system (930 nm) and images were analyzed using the ImageJ software. It was measured the marginal gaps, and the presence of bubbles, filler accumulations and cracks. The qualitative analysis also evaluated the presence of steps, material excess and defects resulting from the finishing and polishing of the restorations. Data were statistically analyzed (ANOVA, p < 0.05). Gaps were found in most of the restorations performed, and some significant differences between the different resins were found, considering the size of the gaps detected. The Surefil SDR resin showed the highest number of internal bubbles and defects, while the X-tra Base resin showed no bubbles or structural defects. Detection of polishing errors, excess of material and cracks were also possible with the use of OCT. It was demonstrated the feasibility of this technique in quality assessment and monitoring of clinical performance of class II restorations performed with bulk-fill composite resins, which can predict the longevity of this treatment.