Studies of the action of sodium fluoride on human enamel by electron microscopy and electron diffraction
Scott, D.B.; Picard, R.G.; Wyckoff, R.W.G.
Public Health Reports 65(2): 43-56
ISSN/ISBN: 0094-6214 PMID: 15403685 DOI: 10.2307/4587209
Electron micrographs have been made of replicas of the surfaces of enamel slabs treated with NaF solns. for lengths of time between 5 min. and 30 days. Few visible surface changes were recognized when the treatment was less than a wk. Small amts. of deposit were noted after 7 days. Greater quantities were seen after 15- and 30-day treatments. It was not visible after the prolonged washing of 30-day treated specimens. Preliminary but inconclusive tests were made of the relative acid solubilities of untreated enamel and enamel after immersion in NaF. Electron diffraction patterns have been made from the sur-faces of enamel slabs before and after immersion in NaF for periods from 3 min. to 30 days. In all instances the original apatite pattern was converted to that of CaF2- The CaF2 pattern reverted to that of apatite when specimens treated for 3 min. with NaF were washed for 90 min. in water, but when specimens treated for 30 days were washed for 6 days the reversion did not occur in all instances. Electron micrographs of surfaces after diffraction showed amts. of deposit to be expected from the treatments they had undergone.