Histological Evaluation of Fixation with Pine Honey and Propolis as an Alternative to Formalin in Oral Tissue

Formaldehyde-based fixatives, particularly 10% neutral buffered formalin (NBF), remain the reference standard in histopathology. However, the fact that formaldehyde is a Group 1 carcinogen has led to research into safer and more environmentally sustainable alternatives. This study aimed to evaluate the histomorphological preservation efficacy of propolis and pine honey as natural fixatives in oral tissues.

Sheep tongue and buccal mucosa specimens were fixed in 10% NBF, 10% propolis, 10% pine honey and a combination of 5% propolis + 5% pine honey for 24 hours. Tissue morphology was assessed using a semi-quantitative scoring system.

The NBF group demonstrated optimal preservation across all evaluated parameters, with well-defined epithelial architecture, homogeneous nuclear chromatin and minimal stromal artifacts. Propolis provided moderate but diagnostically acceptable preservation, characterised by mild epithelial shrinkage and slightly reduced staining intensity. Pine honey showed comparable moderate preservation, with evidence of cytoplasmic shrinkage. The combination group demonstrated improved structural integrity compared to honey alone, demonstrating enhanced cellular boundary definition and basement membrane continuity. 10% NBF maintains its superiority in preserving histomorphological structure, while propolis, especially in combination with pine honey, provides good tissue preservation. These findings support the benefits of honey as a safer alternative for histological applications in research.