Dental pulp tissue engineering

Abstract

Dental pulp is a highly specialized mesenchymal tissue that has a limited regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that has demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article reviews the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and provides insightful information to readers about the different aspects involved in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The findings collected in this literature review show that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable goal and the next decade will certainly be an exciting time for dental and craniofacial research.

Figure 1

SEM – A – Lower magnification of DPSC cells growing in a tooth/slice scaffold. B – Higher magnification of DPSC cells attached to the porosity wall in a synthetic polymer (PLLA) scaffold.

Figure 2

Two strategies to develop injectable scaffolds: using microspheres or self-assembly peptides. A – Interaction of dental pulp stem cells (DPSC) in the Puramatrix®, after 72 hours of suspension. Courtesy of Dr. Benjamin Zeitlin. B - Merged image of DPSC adhered to the micro spheres, as a strategy of producing an injectable scaffold to deliver the cells inside of the root canal.

Figure 3

Histological analysis of pulp tissue. A – HE staining of a normal pulp showing the odontoblast layer aligned at the predentin interface (400X). B – Odontoblast-like cells aligned under the dentin barrier formed after 28 days of direct pulp capping with calcium hydroxide (400x). C – Pulp-like tissue formed in a tooth/slice scaffold after 28 days of implantation in the back of a SCID mice. Note that the histological features resemble more the tissue under the dentin barrier (B) than the normal pulp (A), specially considering the lower number of odontoblast-like cells at the interface (400x).