Major outcomes of clinical and experimental studies to highlight the importance of using silane in composite resin restorations in modern dentistry: a systematic review

Abstract

Introduction: Dental restorations are often placed due to caries or fractures, and composite resin is often the material of choice to restore teeth. Several factors may play a role related to the application of silane coupling agents, such as the type of silane (hydrolyzed or non-hydrolyzed) and the service life of the defective composite resin restoration being repaired. Objective: It was to analyze the main outcomes of clinical and experimental studies to highlight the importance of using silane in composite resin restorations in modern dentistry. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from February to April 2024 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 111 articles were found, 36 articles were evaluated in full and 30 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 30 studies with a high risk of bias and 22 studies that did not meet GRADE and AMSTAR-2. Most studies did not show homogeneity in their results, with X2=78.4%>50%. It was concluded that the previous application of silane reduced the bond strength values. The two-bottle adhesive showed better results than single-bottle or self-etching systems for composite resin repairs. Furthermore, the association of preheated hydrofluoric acid/silane applied or not with electric current promoted different values of micro shear resistance, types of fracture, and contact angles in the resin cement/ceramic connection. Silane application is essential for surfaces conditioned by hydrofluoric acid, but the use of adhesive is optional when silane is applied.