Methods: Polished bovine enamel specimens were randomly assigned to one of four treatment groups (n=10). Artificial erosive lesions were prepared by exposure to 1.0% citric acid pH 3.8 for 30min. Each treatment group was brushed (Oral B Vitality Precision Clean®/EB 17-flexisoft head®) twice a day (morning and evening) over two days with a dentifrice and rinsed with mouthrinse. Between treatments the specimens were incubated in unstimulated human saliva. Treatment groups were (i) fluoride free (placebo) dentifrice in combination with Sensodyne® Pronamel® mouthwash (ii) Sensodyne® Pronamel® dentifrice in combination with Sensodyne® Pronamel® mouthwash, (iii) Fluoride free (placebo) dentifrice in combination with Listerine® Enamel Guard® mouthwash (iv) Colgate® Cavity Protection dentifrice and Listerine® Enamel Guard® mouthwash. The degree of lesion rehardening was assessed by surface microhardness (Knoop). Between treatment statistical analysis was conducted using unpaired Student t-test. Chemical mapping and surface topography was conducted to aid interpretation of results.
Results: An increase in Knoop surface microhardness was observed in all treatment groups at all time points. However, the Sensodyne Pronamel dentifrice and Pronamel mouthrinse regime group exhibited statistically significantly superior rehardening (p<0.0001) versus all other treatment groups at both 24 and 48h time points. The placebo dentifrice and Sensodyne Pronamel mouthrinse regime group demonstrated statistically superior rehardening (p<0.0001) at 24 and 48h compared to the placebo dentifrice and Listerine Enamel Guard mouthrinse.
Conclusion: An oral care regime consisting of Sensodyne Pronamel dentifrice and Sensodyne Pronamel mouthrinse provides statistically significantly greater artificial lesion rehardening then comparator formulations and regimes within this in vitro model.