Effect of Oxygen-Inhibited Layer of Dental Adhesives on Bond Strength: A Systematic Review

The aim of the study was to evaluate the effect of the oxygen-inhibited layer on the bond strength of dental adhesives. The protocol was registered in PROSPERO. PRISMA 2020 guidelines were followed. The focused structured question using Population (P), Intervention (I), Comparison (C), and Outcome (O) was: "What is the effect of oxygen inhibited layer on bonding strength of dental adhesives?" The literature was screened via PubMed, Google Scholar, Scopus, and Web of Science. The last search was carried out in September 2024 with an English language restriction. Two reviewers independently performed screening and evaluation of articles. A total of 71 articles were retrieved from databases, in which only 35 articles were selected for full-text analyses. After implementing the exclusion criteria, eight studies were evaluated and included in the review. The results showed that the presence of an oxygen-inhibited layer led to an increased bond strength when light-cured composite resin was used, but there was a decrease in bond strength and an increased bond failure rate when chemically cured composite was used upon dental adhesive application. Meta-analysis could not be performed due to heterogeneity in the studies. The presence of an oxygen-inhibited layer is beneficial in improving the interfacial bond strength when used with light-cured composite resin (when light curing was performed in accordance with the manufacturer's instructions).