Fluoride release and mechanical properties of S-PRG fillers in dental materials: a systematic review and...

This systematic review aimed to assess the fluoride release and selected mechanical properties (direct tensile strength [DTS], flexural strength, and wear resistance) of S-PRG-containing dental materials.

A search was conducted using PubMed, Scopus, ScienceDirect, and Google Scholar according to the PRISMA guidelines. Qualitative data were pooled narratively, and quantitative data were synthesized statistically in RevMan 5.4 using a random-effects meta-analysis. Subgroup analyses of DTS and flexural strength were conducted where appropriate. The risk of bias was assessed using the QUIN tool, and GRADE was used to assess the certainty of the evidence.

Of the 216 studies identified, 18 were deemed eligible. Seven studies provided quantitative fluoride-release data for the meta-analysis. The meta-analysis revealed an overall statistically significant difference between S-PRG-containing materials and comparators (mean difference: -3.21; 95% CI: -4.12 to -2.30; p < 0.01) with very high heterogeneity between studies (I² = 98%). Subgroup meta-analyses of mechanical property comparisons revealed pooled estimates of 6.50 and 11.20 for the DTS and flexural strength comparisons, respectively. Both comparisons showed extreme heterogeneity between studies. Most studies demonstrated a moderate risk of bias, and the certainty of evidence was low.

Owing to their composition, S-PRG-containing materials might have the potential for fluoride release and may have different mechanical properties compared to comparator materials. Nevertheless, there is insufficient evidence owing to the extreme heterogeneity and high number of in vitro studies. Therefore, the interpretation of these findings should be made with caution, and future investigations should use standardized testing protocols and well-designed clinical trials.