Effects of 5000ppm Fluoride on the Demineralization of Dentin Surfaces

Objectives: The purpose of this study was to evaluate the effect of a 5000ppm fluoride toothpaste on demineralized dentin surfaces. Methods: Dentin specimens were created by preparing the cervical regions of 45 extracted human third molars. The specimens were embedded in epoxy resin and polished to 4000 grit. Subsequently, the surfaces of the specimens were partially covered with a self etching adhesive system, thus serving as a control surface. Additionally, three intraoral appliances made from acrylic resin were created. Each 15 specimens were inserted into the lingual aspect of the appliances which were worn by one test person 24 hours a day for a period of three weeks. This was followed by 1 week of recess before the person wore the next appliance. During meals, the appliances were stored in 10% sucrose solution. To assess the effects of a 5000ppm fluoride toothpaste (Duraphat) (n=15), a 250ppm fluoride mouth rinse (Meridol) (n=15) and a placebo (n=15) as a negative control group, dentin specimens were randomly assigned to the three groups mentioned . Once daily, the appliance was immersed in either a toothpaste slurry, a mouth rinse or distilled water for 60 seconds. Demineralization was assessed by tranversal microradiography. The microradiographic technique was used to assess lesion depth (µm) and mineral loss (vol%µm). Data analysis was accomplished using Kolmogorov-Smirnov, analysis of variance (p<0.05) (SPSS 12.0). Results: There were statistically significant differences for mineral loss and lesion depth between the toothpaste (80.40%µm, 7.80µm) and the mouth rinse (225.80%µm, 20µm) and between the toothpaste and the control group (368.10%µm, 16.70µm). There were no statistically significant differences for lesion depth and mineral loss between the mouth rinse and the placebo group. Conclusion: The results suggest that treatment with a toothpaste containing 5000ppm fluoride may considerably reduce mineral loss and lesion depth on exposed dentin.