Regerneration Potential of the Young Permanent Tooth: What Does the Future Hold?

Author(s): Hargreaves KM, Giesler, T, Henry M, Wang Y.
Journal: Pediatric Dentistry
Volume (number): Volume 30, Number 3
Month, Year: May/June 08
Major topic: Regeneration of Pulp
Minor topic(s): none
Type of Article: Literature Review
Purpose: This article reviews the literature as it relates to biologically based endodontic therapies like pulp revascularization and regeneration of a vital pulp/ dentin complex. The author discusses a format for future research into this area of endodontics.
Findings: Several parameters have been established in the literature to promote regeneration of the pulp. (1) It is more effective in immature teeth with wide open apices. (2) Instrumentation and bleach irrigation is inadequate to create needed conditions for revascularization of a necrotic tooth. Most cases used NaOCl (bleach) as an irrigant to cleanse the pulp chamber and root. (3) Calcium hydroxide prevents revascularization. (4) The triple antibiotic paste consisting of Ciprofloxacin, Metronidazole, and Minocycline effectively disinfects an infected necrotic pulp and promotes revascularization. A blood clot is then stimulated to provide a protein scaffold allowing tissue ingrowth into the pulp. As a result these studies show continued thickening of the dentinal walls and apical closure. In summary, these case reports can act as a foundation to generate future prospective clinical trials.
The author continues with a discussion of three components of tissue engineering as it relates to the pulp. Mesenchymal progenitor cells from the dental pulp, apical papilla or elsewhere can develop into odontoblastic cells. However the origin and type of cells remain unknown as the tissue in human teeth has not been evaluated histologically. A clot acts as a scaffold which is necessary to stimulate differentiation of these undifferentiated stem cells and provide a nutrient filled environment to facilitate growth. The author discusses platelet rich plasma as a substance that contains growth factors and forms a fibrin matrix for pulp regeneration. The last component are signaling molecules like growth factors and other substances that can stimulate cell proliferation and direct cell differentiation into odontoblasts/ osteoblasts, etc Examples of signaling molecules include dexamethosone or EDTA.
Future paths of exploration for regeneration of pulp tissue were mentioned. Instead of gene tranfection or growth of artificial teeth, the authors suggest focusing on finding signaling molecules at the apex of the tooth and then designing a scaffold for proliferation
Assessment of article: Good article from a symposium given by AAPD