Nondestructive assessment of current one-step self-etch dental adhesives using optical coherence tomography

This study aimed to nondestructively evaluate sealing performance of eight one-step self-etch adhesives (1-SEAs) using optical coherence tomography (OCT). The two-step self-etch adhesive (2-SEA) served as the control. Round tapered class-I cavities (D ¼ 4 mm, H ¼ 2 mm) were prepared in bovine incisors, treated with each adhe- sive (n ¼ 5), and restored with a flowable resin composite. Cross-sections were obtained from each restoration using swept-source OCT with 1310-nm laser. The average percentage of the sealed interface (SI%) for each adhe- sive was calculated using image analysis software, considering increased signal intensity at the interface as gap. Samples were then sectioned and observed under confocal laser scanning microscope (CLSM). Significantly differ- ent SI% values were found among different adhesives (analysis of variance, Bonferroni, p < 0.05). There was also a significant correlation in SI% between OCT and CLSM (p < 0.0001, r ¼ 0.96). Additionally, microscopic analysis revealed that the gaps in 1-SEAs occurred not only at dentine-adhesive interfaces but also frequently at adhesive- composite interfaces. Some recent 1-SEAs could achieve reliable short-term sealing comparable to 2-SEA. OCT is a unique tool to nondestructively evaluate the sealing performance of the restoratives through the cavity, provided that cavity walls have a certain minimum inclination with respect to the beam.©TheAuthors.PublishedbySPIEunderaCreative