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

OBJECTIVES: Assessment 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). METHODS: 16 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. RESULTS: At 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). SIGNIFICANCE: Given 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.