Remineralisation of enamel and dentine with stabilised stannous fluoride dentifrices in a randomised cross-over in situ trial

Objectives: To compare the remineralisation efficacy and ion bioavailability of two novel SnF2-containing dentifrices in a blinded, cross-over, randomised in situ clinical study. Methods: Six participants wore removal palatal appliances holding human enamel and dentine blocks with subsurface lesions. Appliances were worn for two treatment periods of 14 consecutive days each, with a oneweek washout period in-between. Participants were randomly allocated to rinse with a 1:5 diluted coded slurry of one of two dentifrices containing either 5 % casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) +1100 ppm F as SnF2 [MIPOP], or 1100 ppm F as SnF2 [CT], for 1 min, four times a day. Saliva was collected post-treatment and analysed for tin, calcium, inorganic phosphate and fluoride ions using atomic absorption spectrophotometry and ion chromatography. Enamel and dentine lesions were analysed for percent remineralisation (%R) using transverse microradiography and percent surface microhardness recovery (% Results: MIPOP released significantly higher F (3.00 +/- 0.27 mM), Ca (15.23 +/- 3.23 mM) and Sn (1.18 +/- 0.13 mM) into saliva whereas CT released 2.89 +/- 0.32 mM F and only 0.84 +/- 0.11 mM Ca and 0.28 +/- 0.10 mM Sn. MIPOP produced significantly higher %R than CT: 25.6 +/- 1.5 % compared to 15.2 +/- 0.7 % in enamel, and 33.6 +/- 3.1 % compared to 20.6 +/- 1.1 % in dentine. Additionally, MIPOP produced significantly higher %SMHR (18.2 +/- 7.9 %) compared to CT (4.1 +/- 0.6 %). Conclusions: Both dentifrices promoted remineralisation, but the MIPOP dentifrice with added CPP-ACP and the ion-stabilising effects of CPP released higher amounts of bioavailable tin and produced significantly higher remineralisation and surface microhardness recovery. Clinical Significance: Modern dentifrices contain SnF2 for a range of oral health benefits. Challenges associated with stability of these formulations can affect ion bioavailability, reducing efficacy. Two dentifrices with SnF2 promoted remineralisation in situ, however the dentifrice with the added saliva biomimetic CPP-ACP was superior and therefore may produce greater health benefits.