In Situ Remineralisation Response of Different Artificial Caries-like Enamel Lesions to Home-care and Professional Fluoride Treatments

This study mainly compared the response of the artificial carious enamel lesions to remineralisation in situ. The tested in vitro demineralising protocols were: MC gel, PA gel, MHDP and Buffer solutions. The lesions were then remineralised in an in situ model, with crossover and double blind design. Fifteen volunteers wore intra-oral appliances containing 2 bovine enamel samples of each demineralising protocol during 3 experimental phases (3 days each). The experimental phases/treatments were: Control (Placebo dentifrice, saliva effect only), Home-care (fluoride dentifrice, 1,100 ppm F, NaF), and Professional/Home-care (varnish- 22,600 ppm F and dentifrice- 1,100 ppm F, NaF). During the 3-day phase, the appliance was only removed during the main meals (four times a day, maximum 1 h duration each, interval between meals 2-3 h). Immediately after the meals, before replacing the appliance in the mouth, the subjects were advised to perform oral hygiene using a soft end-rounded toothbrush (Colgate® 360º Sensitive Pro-Relief TM) and dentifrice (non-fluoridated from IceFresh, Bauru, SP, Brazil or fluoridated dentifrice from Crest Procter \& Gamble, Cincinnati, OH, USA) according to the phase and dental floss (Sanifill, São Paulo, Brazil). The remineralising treatment with dentifrices was done ex vivo, 1 min twice a day (after the first and last oral hygiene of the day) using slurry of the dentifrice (1:3 water, 1 drop of solution/specimen). Thereafter, the appliance was replaced in the mouth and the subjects were advised to rinse with 10 ml of water for 5 s and to expectorate. In respect to Professional/Home-care phase, the varnish (Duraphat, Colgate, SP, Brazil) was applied before the in situ study for 6h and then removed. The enamel remineralization was quantified using transverse microradiography (% mineral recovery and lesion depth, TMR), surface and cross-sectional hardness. The data were submitted to statistical analysis (p\<0.05).