PubMed1975
An enamel biopsy method was developed that is especially intended for use under primitive clinical conditions in field studies. Three successive enamel layers, each of 1 mum or less, were etched off the same delimited area of 3 mm2 by means of perchloric acid, using a microsampler with disposable tips. The biopsy technique was applicable to the vestibular surface of almost all teeth, causing no perceptible damage to the enamel surface. Based on cumulated data from the successive enamel layers, curves were drawn from which F levels at various depths in the outer 3 mum of the enamel could be interpolated. F levels in surface enamel of maxillary first premolars in 40 12-13-year-old children in a locale with 0.5 mg F/l in the drinking water were found to be 3,800, 2,400 and 2,000 parts/10(6) in three successive enamel layers of 0.6, 1.0 and 1.1 mum, respectively, demonstrating a decrease in F concentration of about 1,800 parts/10(6) within this depth interval. Identical F concentrations were found in bilateral premolars.