Application of potassium hydroxide and glycerin technique for dental clearing

Dental clearing objective is performed to obtain the translucency of the mineralized structure, allowing an appreciation of the inner architecture of the tooth. It is achieved mainly using the dehydration technique on the sample. On the other hand, there are other techniques used for the study of ossification centers based on the maceration methods using potassium hydroxide and glycerin, none of which have been reported for dental clearing. The purpose of this study was to describe the maceration technique of the dental tissue using potassium hydroxide with a five-year follow up. We selected 40 teeth to complete the sample (10 incisors, 6 cuspid, 10 bicuspids and 14 molars). The teeth were cleaned and then partially decalcified with hydrochloric acid. A quarter of the sample was cleared by classic dehydration method. The other three quarters were cleared with the maceration method, that consisted mainly in a partial maceration using potassium hydroxide baths at low concentrations, followed by the addition of glycerin at ascending concentrations and finally using pure glycerin for an undefined period of time. The maceration technique achieved an adequate clearing of the mineralized tissue with an optimal visualization of the root canal system in the cleared sample. With both techniques it was possibly to clear the teeth but with evident differences. With the first technique the teeth achieved a yellowish color, losing a great amount of dental tissue however the maceration technique sample allowed the preservation of more structure and obtained a coloration similar to the original tooth. With the maceration method the samples were more similar to the original ones than the cleared teeth obtained with dehydration.