Effect of degree of conversion of bulk-fill and incremental layering techniques of composite resin placement on monomer elution: A Systematic Review

This systematic review aims to evaluate the relationship between the degree of conversion (DC) of composite resins and the extent of monomer elution when different placement techniques are used, specifically bulk-fill and incremental layering approaches. Polymerization efficiency is a critical determinant of the clinical success and biocompatibility of resin-based restorative materials. Incomplete conversion of monomers into a stable polymer network may result in the release of residual monomers, which can compromise mechanical properties, longevity of restorations, and biological safety. With the increasing clinical adoption of bulk-fill restorative techniques as an alternative to conventional incremental layering, it becomes essential to understand whether these techniques influence polymerization behavior and subsequent monomer release. The purpose of this review is to synthesize available in-vitro evidence comparing bulk-fill with incremental layering techniques of composite resin placement in terms of degree of conversion and associated monomer elution.