Propolis‐Supplemented Hydrogel as a Transport Medium for Avulsed Teeth: Periodontal Ligament Cell Compatibility, Antimicrobial Activity and Physical Tooth Position Stability

BACKGROUND/AIM: Avulsion of a permanent tooth is a critical dental emergency requiring rapid intervention to optimize replantation outcomes and minimize complications. Conventional storage media maintain periodontal ligament cell viability but often lack sufficient antimicrobial protection and mechanical stabilization during transport. Hydrogels, specifically those combining gellan gum and natural additives like propolis, offer promising improvements by providing enhanced antimicrobial activity and mechanical cushioning. The aim of this study was to systematically evaluate a hydrogel-based transport medium supplemented with propolis and optimized gellan gum concentration for its ability to preserve cell viability, inhibit microbial growth, and confer mechanical stability to avulsed teeth during simulated transport. MATERIAL AND METHODS: Human periodontal ligament fibroblasts (HPLFs) were exposed for 3 or 6 h to phosphate-buffered saline, milk, blank hydrogel, or hydrogel containing 1% water-based propolis extract. Cell viability, morphology, and growth-factor secretion (FGF-2, VEGF-A) were assessed using a scratch-injury model. Hydrogels with 0%, 1%, 2%, and 5% propolis were tested for sterility and antimicrobial activity against 11 microbial strains under varying temperatures. Extracted single-rooted teeth immersed in hydrogels with gellan gum concentrations from 0.2% to 2.5% were subjected to vibration simulation to assess mechanical stability. RESULTS: Hydrogels with or without propolis supplementation were cytocompatible and preserved fibroblast morphology for 6 hours. Both blank and propolis hydrogels enhanced fibroblast growth factor secretion after injury, whereas propolis supplementation uniquely increased VEGF-A release. Hydrogels autoclaved before use remained sterile throughout the study. The 2% and 5% propolis formulations exhibited selective, temperature-dependent antimicrobial activity-particularly against Streptococcus anginosus, Streptococcus mutans, and Bacillus subtilis. Hydrogels containing ≥ 1.2% gellan gum prevented tooth displacement during simulated vibration, indicating effective mechanical stabilization. CONCLUSIONS: A gellan gum-based hydrogel demonstrated potential as a multifunctional transport medium for avulsed teeth by preserving HPLF viability, supporting growth-factor secretion following mechanical injury, providing selective antimicrobial activity, and mechanically stabilizing the tooth during simulated transport. While 2% propolis showed greater antimicrobial activity and was previously demonstrated to be cytocompatible, further evaluation of the 2% formulation using the biological assessment methods applied in the present study is required before an optimal formulation can be established.