Fluoride uptake in enamel after using a fluoride chewing gum

Objectives: The aims of this study were to evaluate the fluoride (F) kinetics in saliva and the F uptake in enamel after using the chewing gum Happydent® (0.3 mg F as MFP). The chewing gum Trident® was used as control. Methods: Ten 8-9 year-old children participated in this double-blind crossover study. They received professional prophylaxis and total saliva (baseline) was collected for 3 min. A circular area (0.9 mm diameter) was demarcated on the buccal surface of the maxillary central incisor and an enamel biopsy (baseline) was obtained using 5 µL of 0.5 M HCl. After 15 sec, the acid was removed and added to 50 µL TISAB. Two separate rinses of the biopsy site, each using 5 µL of 0.25 M NaOH was done. Half the volunteers chewed Happydent® and the other half Trident® and total saliva was colleted for 3 min after 3, 6, 9 and 15 min, while chewing. After the last saliva sample was collected, another acid-etch biopsy was performed on the same tooth. After a week, each volunteer chewed the other gum and sampling was repeated. F was analyzed with the ion-specific electrode. Phosphorus in the biopsies was analyzed spectrophotometrically. The data were analyzed by repeated-measures ANOVA and paired t test (p<0.05). Results: The total mean amount of F released in saliva (±SE, mg) was 0.0550±0.0053 and 0.0016±0.0003 for Happydent® and Trident® respectively and this difference was statistically significant. The mean fluoride uptake in enamel (±SE, mg/Kg) after chewing was 1,600±601 and -470±370 for Happydent® and Trident®, respectively. Conclusions: A high F concentration in saliva and a significant F uptake in enamel were found after the use of Happydent® which suggests this the regular use of this gum may be significant in the prevention of dental caries.