Assessment of defects at tooth/self-adhering flowable composite interface using swept-source optical coherence tomography (SS-OCT)

•Adhesive defects were detected and assessed by optical coherence tomography.•At enamel, EF showed significantly fewer adhesive defects than PLP.•At dentin, EF showed more adhesive defects than PLP.•We would recommend clinical use of EF on very small cavities bounded by enamel.•The use of EF as a definitive restorative material must be put under scrutiny.

ObjectivesAssessment of adhesive defects of a self-etch adhesive and a self-adhering flowable composite at the tooth/composite interface before and after water storage by optical coherence tomography (OCT).Methods16 extracted human molars (n = 8 each) with box-shaped, class-V cavities were restored either with an experimental self-adhering flowable composite (EF, DMG) or with the filling system Adper™ Prompt™ L-Pop™/Filtek™ Supreme XT Flowable composite (PLP, 3M ESPE). Restorations of both groups were non-invasively imaged using swept-source OCT before and after storage in water. The OCT signal for adhesive defects at the tooth/composite interface was quantified.ResultsAt enamel, significantly fewer adhesive defects were detected at EF restorations than at PLP restorations, before water storage (4%/48%, p < 0.001) and thereafter (8%/49%, p < 0.001); in contrast, at dentin more interfacial defects were observed with EF (before water storage: 75%/11%; p < 0.001, after water storage: 77%/52%; pi = 0.001). In the case of slight initial adhesive defects, water storage caused a statistically verifiable increase in adhesive defects at the enamel interface with EF (before/after storage: 4%/8%; p = 0.023) and at dentin with PLP (before/after storage: 11%/52%; p = 0.008).SignificanceGiven the high proportion of adhesive defects with the experimental self-adhering flowable composite, its use as the definitive restorative material in class-V cavities must be critically scrutinized and clinical indications must be investigated further with in vitro and in vivo trials.