This study was performed for the purpose of examining the effects of aqueous solution of sodium fluoride on the remineralization and rehardening of human tooth enamel.
16 pairs of permanent first premolars extracted from Korean were tested. Microhardness test and scanning electron microscopy were investigated on sound enamel, initial carious enamel, enamel treated with sodium fluoride after etched with 30% phosphoric acid and initial carious enamel treated with sodium fluoride, respectively.
The results obtained were as follows:
1. The microhardness value of sound enamel surface was Hv. 347-391, and the mean was Hv. 367.2.
2. The initial carious enamel surface treated with 2% sodium fluoride solution has shown dense appearance in. SEM, but the increase of microhardness value was not remarkable.
3. Enamel surface etched with phosphoric acid and then treated with 2% NaF solution was changed to relatively dense structure in SEM, but the microhardness value was only Hv. 238.2.
4. The mean microhardness value was highest in sound enamel (Hv. 367.2) and followed by
fluoride solution-treated initial carious enamel (Hv. 293.0), initial carious enamel (Hv. 291.3)
and fluoride solution-treated etched enamel (Hv. 238.2) in order.
5. The microhardness value of the substance formed initially on the carious or etched enamel surface by application of 2% NaF solution was very low.
|