Evaluation of Aluminum Chloride-based Hemostatic Agents in Endodontic Microsurgery: An In Vitro and In Vivo Preclinical Study.

Introduction: While the aluminum chloride-based hemostatic agent Expasyl is proposed for efficient hemostasis in endodontic microsurgery, its high viscosity may hinder removal and lead to adverse tissue reactions. Traxodent, with lower viscosity, is less studied. This study preclinically compared Expasyl and Traxodent to evaluate (1) cellular responses in human osteoblasts (HOBs) and (2) hemostatic efficacy and tissue response in a rabbit calvarial model.

Methods: HOBs were cultured in media containing high and low concentrations of each agent to assess short- and long-term effects. Cell viability was assessed using the Cell Counting Kit-8 assay, and osteogenic (ALPL, BGLAP, RUNX2) and inflammatory (interleukin 6, C-X-C motif chemokine ligand 8, transforming growth factor beta 1) gene expression were analyzed via reverse transcription-quantitative polymerase chain reaction. In vivo, six calvarial bone defects were surgically created in each of six rabbits. Defects were randomly assigned to six groups: control, epinephrine, Expasyl, or Traxodent with or without curettage. Hemostasis was evaluated using photographic bleeding scores. Histological analysis assessed tissue response and bone healing.

Results: Short-term exposure (2 min - 1 h) to Expasyl or Traxodent reduced HOB viability. Expasyl significantly decreased transforming growth factor beta 1 and increased C-X-C motif chemokine ligand 8 expression. Both agents reduced osteogenic markers. Expasyl showed the highest hemostatic efficacy but also induced more inflammation and delayed bone healing based on histological findings. Traxodent was easier to remove, left minimal residue, and did not impair healing but demonstrated no significant improvement in bleeding control.

Conclusions: Expasyl provided effective hemostasis but was associated with delayed healing and inflammation. Both agents showed cytotoxicity and reduced osteogenic gene expression. Residual Expasyl may hinder healing in endodontic microsurgery.