Copolymerizing flowable and high-viscosity composite resins in class II restorations: The “Snowplow” technique. A scoping review

Statement of problem: Copolymerizing flowable and high-viscosity composite resins is a restorative approach developed to improve marginal adaptation in Class II direct composite resin restorations. Also known as the “Snowplow technique,” its effect on clinical performance remains unclear. Purpose: The purpose of this scoping review was to evaluate the efficacy of the copolymerizing flowable and high-viscosity composite resins in Class II direct restorations. Material and methods: A systematic search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) was performed on 4 databases (Embase, Medline, Scopus, Web of Science) for articles published before January 2025. The study selection was then performed by 2 authors, who screened the abstracts independently and followed the JBI approach. Results: Of 612 screened abstracts, 36 were selected for full-text analysis. Finally, 19 studies were included in this review. Both in vivo and in vitro studies on Class II composite resin restorations using the copolymerizing flowable and high-viscosity technique were analyzed; studies on class I, class V, and primary teeth were excluded. Conclusions: Findings were inconsistent regarding microleakage, marginal adaptation, and mechanical properties. Overall, the current evidence is insufficient to definitively support or refute the efficacy of copolymerizing flowable and high-viscosity composite resin in class II restorations.