Is the author writing about the same article I read? I didn't read the whole paper, but from the abstract I understood that the study was looking at the effect of replacing pulp cells, NOT repairing carious lesions. Even so, I have a few problems with the basic histology of the concept.
First of all, in endodontic treatment, the pulp is removed. This leaves no cells. You can't increase the proliferation of something that isn't there.
The abstract mentions that "These effects suggest a novel use of PGA-α-MSH as an anti-inflammatory agent in the treatment of endodontic lesions." So, are they suggesting that you can squirt some of it into a tooth with pulpitis, and by decreasing the inflammation the tooth will be healed? They're forgetting that the cause of the problem is bacteria, and as long as bacteria is present in the diseased tissue you can reduce inflammation all you want, but without eliminating the root of the problem any treatment will be ineffective. Hence, the need to remove the cells.
As for healing caries, in the blogger's interpretation: Although odontoblasts can lay down reparative dentin, it takes ameloblasts to form enamel. There are no ameloblasts left once enamel formation is complete, so it is impossible to regrow enamel from the inside of the tooth.
