RESUMEN
Objective:To determine the fluorine content in enamel before and after besmearing fluoride varnishes or fluorinated bubbles. Methods:Thirty patients whose deciduous central incisors will be extracted were divided into group a and b randomly. For the same patient, a pair of mandibular deciduous central incisor were chosen. For group a: one tooth was removed, and the other one besmeared with fluoride varnishes and removed 24 h later. For group b: one tooth was removed, and the other one besmeared with fluorinated bubbles and removed 24 h later. The fluorine contents in the enamel of every tooth were determined by neutron activation method and analyzed statistically. Results:For group a: the fluorine content in the experimental group was (142.78?42.25) ?g/g, and that in the control group was(119.62?38.62) ?g/g. For group b: (162.36?31.36) ?g/g and (126.56?38.42) ?g/g respectively. The fluorine content in the enamel of tooth besmeared with fluoride varnishes or fluorinated bubbles was higher than that in the control group(P