Self-Adhesive Flowable Resin Composites-Are We Going Somewhere?

To map laboratory/clinical evidence on self-adhesive flowable resin composites (SAFRCs), tracing their chemical evolution, performance, and behavior, and to identify gaps that must be addressed to drive their optimization.

A comprehensive literature search was performed in PubMed/MEDLINE, Scopus, and LILACS without language restrictions. To date, 11 commercial SAFRCs are available. These contain 5wt%-10 wt% hydrophilic monomers and ≤ 55 vol% fillers, as a flowable option, although susceptible to water sorption and color changes. Functional monomer trends shift from 4-META/GPDM to 10-MDP or phosphate-amide hybrids; meta-analytical and recent laboratory data confirm that μTBS to dentin is extremely low (rarely > 10 MPa). Inefficacy to bond/seal is the main reason for failure. Clinical evidence is scarce and short-term: RCTs suggest that small Class-I restorations survive comparably to controls at ≤ 24 months, but failures are frequent. Emerging strategies such as alternative conditioning, collagen depletion, or incorporation of bio-interactive fillers may improve outcomes.

Current SAFRCs simplify placement and reduce technique sensitivity but are constrained by very low bond strengths, poor sealing, and high hygroscopicity. Until chemistry, paste acidity, and smear-layer interaction are co-optimized, their use should remain limited. Future research must couple novel chemical formulations and low-water-uptake matrices while validating performance in adequately powered RCTs.