Evaluation of Composite Adaptation to Pulpal Chamber Floor Using Optical Coherence Tomography

A coronal seal is fundamental for a positive outcome to endodontic therapy. In this in vitro study, we evaluated the adaptation of composite resins in postendodontic restorations using optical coherence tomographic (OCT) imaging. Our null hypothesis was that there would be no difference in marginal adaptation to the pulp chamber floor between resin composites of different viscosities.

Thirty intact upper molars extracted for periodontal reasons were selected, endodontically treated, and filled with gutta-percha. The excess gutta-percha was entirely removed from the pulp chamber floor, and teeth were randomly divided into 3 groups (n = 10) according to the material used for the restoration: group 1: 0.5-mm horizontal layer of flowable composite followed by nanohybrid composite, group 2: bulk layering of bulk fill flowable composite; and group 3: oblique layering of nanohybrid composite. The degree of adaptation to the cavity floor was assessed using OCT imaging, and images were analyzed with the software program ImageJ (National Institutes of Health, Bethesda, MD) to assess the marginal gap between the composite and the pulp chamber floor. Collected data were statistically analyzed using analysis of variance testing, and statistical significance was set at P < .05.

Flowable composites showed significantly better adaptation than traditional packable nanohybrid composites (P < .05). All significant differences were found between groups 1 and 2.

Within the limitations of this OCT imaging-based in vitro study, it was concluded that the flowable composite (flow + nanofilled; flow bulk fill composite) adapted better to the pulp chamber floor than the packable nanohybrid composite resin. Further studies are necessary to confirm these results.