Fluoride Uptake in Incipient Enamel Lesions from Mouthrinse Treatments

Objective: The purpose of this in vitro study was to determine the ability of Listerine® Tooth Defense™ (LTD), and two marketed fluoride-containing mouthrinses to promote fluoride uptake into incipient enamel lesions versus a negative control (water). Methods: The test procedure utilized was a modification of Test Method #40 referred in the FDA Monograph. After determining their baseline fluoride content (ppm), an incipient caries-like lesion was created in human enamel specimens using a solution of 0.1M lactic acid and 0.2% Carbopol 907, 50% saturated with HAP (pH 5.0). Specimens were then treated with their correspondent mouthrinse or water for 30 minutes. After treatment, specimens were analyzed again for fluoride content to determine the amount of fluoride uptake (post treatment F – Baseline F). Results: The fluoride uptake (ppm ± SEM) results indicated that the enamel fluoride uptake after LTD treatment (7614.56± 738.57) was higher than that of both positive controls (ACT® and Phos-Flur®; 1075.26± 33.75 and 1985.22± 39.47 respectively), which in turn promoted greater fluoride uptake than water (44.01±6.29). The post-treatment mean fluoride content from LTD was significantly higher than in the sterile water group (p<0.001). LTD was noninferior to both Act and Phos-Flur, and was also significantly better than both Act and Phos-Flur (p<0.001). Conclusion: These data indicated that LTD promoted enamel fluoride uptake, and is non-inferior to the two positive control products. Furthermore, the amount of enamel fluoride uptake was significantly higher for LTD than for the positive controls.