Protein induces dental pulp stem cells into dentin-forming odontoblasts

When dentists examine patients with a damaged tooth that has become infected and abscessed, or filled with tissue-eroding fluid, they typically have two options:  Root canal or extraction. 

But for patients with less advanced infections that have yet to abscess, there is a third, tooth-saving possibility called direct pulp capping.  Much like cleaning and bandaging a wound, the procedure requires the dentist to sterilize the infection, remove all signs of decay, and refill the hole in the tooth to allow the remaining healthy tissue to regenerate.  And therein lies a challenge.  When dentists fill the tooth, they can never be certain that its natural, highly mineralized dentin matrix will reform during the healing process as a needed buffer between the filling and the pulp tissue inside the tooth.  Without an adequate dentin bridge, the direct contact between filling and pulp can irritate the tooth, lead to inflammation, and ultimately additional dental work.

To help dentists solve this problem, scientists have turned their attention to the adult stem cells that reside within the dental pulp and which can be transformed with appropriate stimuli to produce a dentin-secreting cell called an odontoblast.  In the December issue of the journal Gene Therapy, NIDCR grantees report taking an important step forward in learning to coax dental pulp stem cells to differentiate into what appear to be odontoblasts.  Working with laboratory rats, the scientists implanted bits of a collagen protein matrix into the dental pulp of the molars and waited to see what happened.  Each bit was saturated with a recombinant form of a gene called dentin matrix 1(DMP1), which encodes a dentin protein that their earlier work showed can induce undifferentiated mesenchymal cells to differentiate into odontoblast-like cells.  After two and four weeks, they found DMP1 had a similar effect in the rat molars as in their cell-culture experiments, prompting the dental pulp stem cells to differentiate into cells that "had the potential to regenerate dentin-like tissue."  The dentin-like qualities of the regenerated tissue included: newly formed collagen matrix, protein markers for the differentiated cells that are specific to odontoblasts, and calcified deposits.  To read more about this study, click here.

http://www.nidcr.nih.gov