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

Objective: 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. Overview: 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. Conclusions: 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.