Quintessence Int 41 (2010), No. 9 1. Sep. 2010
Quintessence Int 41 (2010), No. 9 (01.09.2010)
Page 773-777, PubMed:20806102
The influence of saliva on the dissolution of calcium fluoride after application of different fluoride gels in vitro
Hellwig, Elmar / Polydorou, Olga / Lussi, Adrian / Kielbassa, Andrej M. / Altenburger, Markus Jörg
Objective: To determine the formation and dissolution of calcium fluoride on the enamel surface after application of two fluoride gel-saliva mixtures.
Method and Materials: From each of 80 bovine incisors, two enamel specimens were prepared and subjected to two different treatment procedures. In group 1, 80 specimens were treated with a mixture of an amine fluoride gel (1.25% F-; pH 5.2; 5 minutes) and human saliva. In group 2, 80 enamel blocks were subjected to a mixture of sodium fluoride gel (1.25% F; pH 5.5; 5 minutes) and human saliva. Subsequent to fluoride treatment, 40 specimens from each group were stored in human saliva and sterile water, respectively. Ten specimens were removed after each of 1 hour, 24 hours, 2 days, and 5 days and analyzed according to potassium hydroxide-soluble fluoride.
Results: Application of amine fluoride gel resulted in a higher amount of potassium hydroxide-soluble fluoride than did sodium fluoride gel 1 hour after application. Saliva exerted an inhibitory effect according to the dissolution rate of calcium fluoride. However, after 5 days, more than 90% of the precipitated calcium fluoride was dissolved in the amine fluoride group, and almost all potassium hydroxide-soluble fluoride was lost in the sodium fluoride group. Calcium fluoride apparently dissolves rapidly, even at almost neutral pH.
Conclusion: Considering the limitations of an in vitro study, it is concluded that highly concentrated fluoride gels should be applied at an adequate frequency to reestablish a calcium fluoride-like layer.
Keywords: calcium fluoride, enamel, fluoride gel, saliva