Silver Impregnation of Nerve Fibers in Teeth After Decalcification With Ethylenediaminetetraacetic ACID

The difficulties in impregnating bony tissues, which occur after decalcification with acids or electrolysis are avoided by decalcification with ethylenediaminetetraacetic acid at pH 8.2-8.5. The decalcification of adult human teeth which have been cut to a thickness of 2-5 mm takes 1-2 mo. If frozen sections of the decalcified teeth are impregnated 24 hr in 20% AgNo₃, rinsed through 6 changes of 20% neutralized (CaCO₃) formalin, blotted thoroughly with a cloth and placed in an ammoniated silver solution for 15-20 min, reliable impregnation of nerve fibers is obtained. The stock ammoniated silver solution is prepared by adding concentrated NH₄OH to 10-20 ml of 20% AgNO₃ until the precipitate formed by it is dissolved and then adding a few drops of the silver solution until the first permanent opalescence of the mixture is obtained. From this 2 ml are diluted directly before use with 6 ml of distilled water and 4 drops of concentrated NH₄OH added. The diluted stock solution should be used for few (5-10) sections only. The rest of the technic is done in the routine manner.