Substantially aqueous-free, enamel protectant and enamel repair toothpastes containing: stannous fluoride, calcium and a substantivity agent comprising: an emulsion of polydimethylsiloxane in a nonionic surfactant, wherein: (a) substantivity of said stannous fluoride and calcium into biofilm present on enamel is enhanced through calcium binding shifting from bidentate to monodentate in the presence of stannous fluoride; and (b) said toothpastes indicate substantially improved, enamel protectant factor (EPF) and enamel repair factor (ERF) values compared to fluoride brushing treatments with comparable or higher fluoride levels.