An evaluation of an in vivo enamel acid etch biopsy technique for fluoride determination.

An in vivo acid etch biopsy method was developed by Hotz et al (1970) to determine fluoride uptake and re­ tention in the outer 5 pm to 15 pm of enamel. This technique was evaluated by means of scanning electron microscopy and planimetry. Because of the difficulty experienced in controlling the areas etched, a modifi­ cation was introduced by defining the biopsy areas with annular adhesive discs. This modified technique was evaluated and the reliability of the method con­ firmed using a surface roughness testing instrument. OPSOMMING