Clinical Efficacy of Bioactive and Smart Restorative Materials in Preventing Secondary Caries: A Systematic Review...

Secondary caries is the primary cause of restoration failure, requiring the replacement of fillings and the progressive loss of tooth structure. Bioactive and smart restorative materials have been developed to combat this by releasing therapeutic ions (fluoride, calcium, phosphate) that promote remineralization and inhibit bacterial growth. However, clinical evidence regarding their efficacy compared with conventional inert materials remains fragmented. This systematic review and meta-analysis aimed to evaluate the clinical efficacy of bioactive restorative materials in preventing secondary caries compared with conventional restorative materials in permanent teeth. A systematic search was conducted across PubMed, Scopus, Web of Science, Embase, and CENTRAL for randomized controlled trials (RCTs) published up to 2025. Studies were included if they compared bioactive materials (glass ionomer cements (GICs), resin-modified glass ionomers (RMGICs), giomers, bioactive resins, alkasites) against conventional controls (resin composite, amalgam) in permanent teeth with a follow-up of ≥12 months. The primary outcome was the incidence of secondary caries. Risk of bias was assessed using the Cochrane RoB 2 tool. Data were synthesized using a random-effects meta-analysis with the Hartung-Knapp-Sidik-Jonkman adjustment. Trial sequential analysis (TSA) was performed to assess the conclusiveness of the evidence. Forty RCTs involving 5,506 restorations were included. The meta-analysis revealed that bioactive materials significantly reduced the risk of secondary caries by 45% compared with conventional materials (risk ratio (RR) = 0.55; 95% CI: 0.46 to 0.65; p < 0.001), with no statistical heterogeneity (I² = 0%). Subgroup analysis showed that GICs provided the strongest protective effect (RR = 0.36; p = 0.002), while giomers did not show a significant benefit (RR = 1.09; p = 0.87). TSA confirmed that the required information size was met and that the evidence for the benefit of bioactive materials is conclusive. The certainty of evidence was graded as moderate due to risk of bias in a subset of studies. Bioactive restorative materials demonstrate a superior ability to prevent secondary caries compared with conventional passive materials. The evidence is robust and conclusive, supporting the use of these materials, particularly GICs and bioactive resins, as a first-line therapeutic choice for patients at high risk of caries. Future research should focus on the long-term mechanical longevity of newer bioactive resin formulations.