Evaluation of mouthrinse and dentifrice regimens in an in situ erosion remineralisation model

To compare the effectiveness of dentifrice/mouthrinse regimens in a clinical in situ erosion remineralisation model. Thirty-six subjects completed a randomised single-blind cross-over trial of five treatment regimens. R1: Dentifrice A [1450 ppm fluoride as the sodium salt (NaF), 50000 ppm potassium nitrate (KNO3)] plus 450ppm fluoride (NaF) rinse; R2: Dentifrice A plus sterile water rinse; R3: Dentifrice B (fluoride-free Dentifrice A) plus sterile water rinse; R4: Dentifrice B plus 450 ppm fluoride (NaF) rinse; R5: Dentifrice C (1000 ppm fluorine as sodium monofluorophosphate, 450ppm fluoride as NaF) plus sterile water rinse. Subjects wore a palatal appliance holding eight pre-demineralised enamel blocks. A 60min interval separated in vivo use of dentifrice and rinse with the appliance retained in situ for 4h. Efficacy endpoints were percentage surface microhardness recovery (%SMHR) following remineralisation, and percentage relative erosion resistance (%RER) of recovered specimens following a subsequent in vitro erosive challenge. Statistical analyses included ANOVA and selected twin-tailed t-tests. Mean %SMHR (±SE) was a42.14±1.39, b38.02±1.39, c30.57±1.39, b37.75±1.39 and c30.88±1.39 for regimens R1–R5 respectively (different superscripts denote statistically significant differences (p<0.05) between treatment regimens). Mean %RER (±SE) was a−2.88±2.16, b−14.54±2.16, c−40.05±2.16, a−3.76±2.16 and d−29.48±2.16 for regimens R1–R5 respectively. R1 elicited statistically significantly greater %SMHR versus all comparator regimens (p<0.01), and conferred statistically significantly greater %RER than comparator regimens (p<0.0001) except R4 (p=0.70). The combination treatment of dentifrice A containing 1450 ppm fluoride with the 450ppm fluoride mouthrinse elicited significant enhancements in rehardening of incipient enamel erosive lesions, and significantly increased their subsequent resistance to a second erosive challenge.