Tooth decalcification using different decalcifying agents - A comparative study

In microscopic assessment of mineralized tissue, decalcification is an important step during tissue processing. The present study was attempted to compare the efficacy of various decalcifying agents and to evaluate the most efficacious decalcifying agent.

The aim was to study and compare the time taken for complete decalcification of the specimen by six different chemical agents; to study and compare the effect of various decalcifying agents on cellular and nuclear changes of hard and soft tissues; to study and compare the effect of various decalcifying agents used on the staining intensity with Ehrlich's Hematoxylin and Eosin stain and to determine the ideal decalcification technique.

The six decalcifying agents, namely 5% nitric acid, 8% formic acid, formalin-nitric acid, 5% trichloroacetic acid, neutral ethylenediaminetetraacetic acid (EDTA) and Perenyi's fluid were used to decalcify 30 human permanent teeth (5 teeth in each solution). The endpoint of decalcification was evaluated by chemical (calcium oxalate test) as well as radiographic methods. The specimens were then subjected to processing, sectioning and staining with hematoxylin and eosin. The stained sections were observed under a light microscope and grading was done.

The results in the present study confirmed the fact that the time required for complete decalcification process was least in Perenyi's fluid, 5% trichloroacetic acid and highest in 14% EDTA. Teeth decalcified in 5% trichloroacetic acid, 8% formic acid, formalin-nitric acid and 5% nitric acid were easy to section. Sectioning was most difficult for teeth decalcified in Perenyi's fluid and 14% EDTA. The overall structure details as well as staining characteristics were best in teeth decalcified by 5% trichloroacetic acid and neutral EDTA and worst in teeth decalcified by Perenyi's fluid.

Five percent trichloroacetic acid was showing the most efficient result as it balances both tissue integrity and time factor suggesting that it can be used as a stable decalcifying agent for routine histopathological diagnosis.