Biological effects of dental resin composites on human gingival fibroblasts: a systematic review of in vitro evidence

This systematic review summarized and synthesized the in vitro biological effects of resin composites (RCs) on human gingival fibroblasts (HGFs) to clarify their isolated cellular biocompatibility.

A systematic search was conducted in the MEDLINE/PubMed database using a PECOS framework to identify in vitro studies evaluating HGF responses to RCs. Two independent reviewers screened literature, extracted data, and assessed methodological quality (QUIN tool) and certainty of the evidence (GRADE framework).

Thirty-eight studies comprising 185 distinct experiments across eight outcome measures were included. Marked heterogeneity was observed regarding RC composition (7 categories), specimen geometry, cell lines, and experimental durations. When evaluating cellular survival and damage independently, 27% of cytotoxicity experiments reported significant cell damage/death, while 45% of cell viability assays demonstrated a decreased metabolic activity. DNA damage was prominent, with 50% of 18 experiments reporting significant alterations. Significant increases occurred in reactive oxygen species production (71%) and inflammatory mediator release (62%). Conversely, 85% of morphology experiments showed no significant alterations. The overall certainty of evidence was graded as low to moderate.