Enamel fluoride retention after application of fluoride-containing rubber cups.

PURPOSE: To compare the fluoride retention in bovine enamel after using fluoride-containing rubber cups or a conventional rubber cup in combination with a fluoride-containing polishing paste. MATERIALS AND METHODS: From each of 20 bovine incisors, 5 enamel slabs with a diameter of 3 mm were sectioned and assigned to 5 groups (A,B,C,D,E). Group A was left untreated and served as the negative control. Group B was polished with a rubber cup combined with a fluoride-containing prophylaxis paste for 10 s (Hawe Cleanic). Groups C and D were treated in the same manner by using a fluoride-containing rubber cup with 2,262 ppm or 9,048 ppm fluoride as NaF. Group E enamel was brushed for 10 s with a toothbrush and a slurry of distilled water and fluoride gel with 12,500 ppm fluoride as NaF and AmF (Elmex Gelee) and served as the positive control. Th e specimens were analyzed using the method of Caslavska et al. After determining the KOH soluble fluoride on the enamel surface, the content of structurally bound fluoride was analyzed in three consecutive layers of 30 microm. ANOVA with Bonferroni correction was used for statistical analysis (P< 0.05). RESULTS: For the KOH-soluble fluoride, Groups B and D accumulated more KOH-soluble fluoride than the negative control and less than the positive control. With respect to the structurally bound fluoride, the accumulation in Group D was higher when compared to all other groups. It was concluded that a rubber cup with 9,048 ppm fluoride may be an effective alternative to the use of a fluoride-containing prophylaxis paste.