Clinical features of erosive tissue loss at early stage are an initial loss of tooth shine or luster, followed by softening of enamel surface. Fluoride ion is known to be effective for preventing mineral loss and re-hardening eroded enamel in vitro.
Objectives: The aim of this study was to evaluate the enamel protection effect of newly developed a 1450 ppm NaF, silica-based toothpaste.
Methods: Polished bovine enamel specimens were divided into three groups, the 1450 ppm NaF toothpaste group, 1000 ppm NaF toothpaste group, and negative control (fluoride free). All the toothpastes were silica-based. Each group was subject to a daily regimen including four erosion/remin cycles and three 2-min treatment at the beginning, middle, and end of the erosion/remin cycles. After the final treatment, specimens were immersed in artificial saliva containing an aliquot of the toothpaste slurry to mimic in vivo carry over overnight. Each erosion/remin cycle comprised a 10-min acid erosion (1% citric acid, pH 3.8) followed by a 1-h immersion in artificial saliva. The acid solution was chosen to mimic orange juice in terms of pH and total titratable acidity. Surface Microhardness (SMH) was measured both before and after treatment.
Results: The baseline and post treatment SMH of enamel specimens in each group was, 1450 ppm NaF group: 311.3±30.6/258.7±20.8, 1000 ppm NaF group: 321.0±16.4/223.5±16.9; negative control group: 312.3±20.0/91.3±8.0. Enamel surface was significantly softened by citric acid in all groups (p<0.001), but 1000 ppm and 1450 ppm NaF toothpaste reduced 56% and 76% SMH loss compared to negative control (p<0.0001). 1450 ppm NaF toothpaste provided 20% greater enamel protection than 1000 ppm NaF toothpaste (p<0.01).
Conclusions: The results showed that 1450 ppm NaF toothpaste provided superior enamel protection against acid erosion than regular 1000 ppm NaF toothpaste. Higher fluoride toothpaste could provide a better erosion control benefit.