The erosive potential of commercially available mouthrinses on enamel as measured by Quantitative Light-induced Fluorescence (QLF)

Design. Longitudinal in vitro. Methods. Previously extracted, caries free, human premolars were selected and prepared by gentle pumicing and coating in an acid-resistant nail-varnish save for an exposed enamel window on the buccal surface. Each was assigned to one of eight groups (six per group, 10 in positive control); positive control (citric acid, pH 2.7, F− 0 ppm), negative control (pH 7.0, F− 0 ppm) Listerine (pH 3.87, F− 0.021 ppm), Tesco Value (pH 6.05, F− 289.00 ppm), Tesco Total Care (pH 6.20, F− 313.84 ppm), Sainsburyʹs (pH 6.15, F− 365.75 ppm), Sensodyne (pH 6.12, F− 285.30 ppm) and Corsodyl (pH 5.65, F− 0 ppm). The titratable acid values (TAV) for each rinse were established using volume (ml) of 0.1 M NaOH to achieve pH 7. Fluoride values were obtained by ion selective electrode. The solutions were kept at 37 °C and gently agitated. Teeth were removed at hourly intervals for 15 h, air-dried and subjected to Quantitative Light-induced Fluorescence (QLF) examination by a blinded examiner and ΔQ values recorded. At the conclusion of the study each of the positive control teeth and one from each other group were sectioned through the eroded lesion, ground and polished to 100 μm and subjected to transverse microradiography and ΔZ recorded for validation. Results. TAVs were: Listerine 2.45 l>Sainsburyʹs 0.35 ml>Tesco Total Care 0.14 ml>Tesco Value 0.08 ml>Corsodyl 0.10 ml>Sensodyne 0.9 ml. ΔQ increased over time for the positive control, (0 h 0.2, 10 h 95.2, 15 h 152.3). Negative controls remained stable. The increase in ΔQ for each rinse after 15 h was Listerine (9.3(±7.2)), Corsodyl (1.5(±1.2)), Tesco Value (1.8(±1.2)), Tesco Total Care (1.4(±1.1)), Sainsburyʹs (3.4(±2.2)), Sensodyne (0.9(±1.6)). TMR confirmed the presence/absence of erosive lesions. Conclusions. QLF effectively monitored erosion in the positive controls and lack of erosion in the NC. Only one mouthrinse (Listerine) caused any erosion compared to the negative control, but this was only significant after 14 h of continuous use.