An innovative gel that forms a layer over teeth and then recruits calcium and phosphate ions from saliva to build new enamel has the potential to change dental treatment. To date, we don't have any way to regenerate the tough outer layer of enamel on our teeth as it erodes with age.
Just from that, it seems like its a patch job, not capable of regrowing from zero.
To be fair, the research is on regenerating, not regrowing. I wouldn’t expect regrowing lost teeth to be possible any time soon, unless some kind of bio 3D-printing method became available.