The effect is to cause the surface exposed to dentin to oxidize more than tin would do alone; in that there is a benefit.
Nature will not restore the lost part, but will do the next best thing—solidify the dentin.
Still, it can easily be renewed, or if all the tin is removed we find the dentin hard and firm.
dentin den·tin (děn'tĭn) or den·tine (-tēn')
The main, calcareous part of a tooth, beneath the enamel and surrounding the pulp chamber and root canals.