Nonformalin Fixative Agents: A Comparative Study of Fixative Efficacy and Histomorphology

Formalin is a gold standard fixative agent. However, formalin possesses health hazards and is not always available in rural areas. The objective of this study was to compare tissue fixative efficacy of nonformalin fixative agents with formalin.

Oral tissues obtained during impacted tooth removal were collected. The tissue fragments were sectioned and fixed in 4 different fixatives; 30% jaggery, 70% ethanol, 2% mepivacaine with 1:100 000 epinephrine, or formalin for 24 and 72 hours. All specimens were then immersed in formalin for another 24 hours and processed according to standard protocol. Hematoxylin and eosin-stained sections were evaluated by a pathologist. The cellular structure, cellular outline, and quality of staining were graded from 1 to 3 and average fixative efficacy scores were compared using 1-way analysis of variance. Fixative artifacts were described.

Fixative efficacy scores of 70% ethanol and 30% jaggery at 24 and 72 hours were not statistically different from those of formalin. Conversely, 2% mepivacaine demonstrated significantly lower fixative efficacy scores than other agents. Although efficacy of each fixative was not statistically different between 24 and 72 hours, efficacy of 70% ethanol was markedly reduced at 72 hours when compared with others. Acantholysis of epithelial cells was the most notable artifact at 72 hours when fixed with nonformalin fixative agents.

Both 70% ethanol and 30% jaggery provided acceptable fixative efficacy at 24 hours. However, only 30% jaggery maintained fixative efficacy at 72 hours. Nevertheless, negative effects on the epithelial cells were unavoidable and should be interpreted with caution.