By Candace DeVeaux DDS

Objectives  Identify the cells found in the dental pulp and their function  Understand what a stem cell is, it’s function, and location  Understand the stem cell’s role in regeneration of teeth-pulp

Cell types found in the dental pulp  Odontoblasts  Fibroblasts  Axons  Endothelial Cells  Schwann Cells  Immune Cells  Smooth Muscle  Stem Cells

Cell types found in the dental pulp Odontoblasts  Specialized cells that deposit dentin lining the outer portion of the pulp Fibroblasts  The most abundant cells of the cell rich zone  Coronal pulp (abundant)  Pulp proper  Form a network within the extracellular matrix components and produce a range of extracellular matrix components ie. Collagen

Cell types found in the dental pulp Axons  Plexus of Raschkow Schwann Cells  Plexus of Raschkow

Cell types found in the dental pulp Immune Cells  Lymphocytes  B Cells  T Cells  Macrophages  Dendritic Cells  Endothelial cells  Various epithelial and mesenchymal Cells Jontell 1998 Smooth Muscle  Pericytes and myofibroblasts have been identified in mineralized human pulp culture. (Alliot-Licht 2001)

STEM CELLS  Different Types of Stem Cells Embryonic Stem Cells Adult/Tissue Specific Stem Cells Induced Stem Cells WHAT ARE STEM CELLS?  A CELL WHOSE DAUGHTER CELLS MAY DIFFERENTIATE INTO OTHER CELL TYPES  Stedman’s Medical Dictionary defines it as a Pre-cursor Cell

STEM CELL USE IN REGENERATIVE ENDODONTICS What is Regenerative Endodontics?  An alternative treatment approach to conventional Endodontic Therapy  Goal- Restore Pulpal Function and complete root development Revascularization vs. Regeneration

Clinical Considerations  1. Young patient  2. Necrotic pulp and immature apex  3. Minimal or no instrumentation of the dentinal walls  4. Placement of an intracanal medicament  5. Creation of a blood clot or protein scaffold in canal  6. Effective coronal seal

STEM CELLS WHAT IS TISSUE ENGINEERING?  INTEGRATION OF BIOLOGICAL AND ENGINEERING PRINCIPLES, to develop substitutes to restore normal function. KEY ELEMENTS

STEM CELLS What type are found in the tooth? 1) Dental Pulp Stem Cells 2) Stem Cells from human- exfoliated deciduous teeth 3) Periodontal Ligament Stem Cells 4) Dental Follicle Progenitor Stem Cells 5) Stem Cells from apical papilla

How the Stem Cells are identified… Stem cell markers  Genes and their protein products used by scientists to isolate and identify stem cells  Various markers for Odontoblasts…  ALP  DMP1/DMP2  DPP  DSP  DSPP  Enamelysin Example:

STEM CELLS in REGENERATION SCAFFOLDS  Cell Organization  Proliferation  Differentiation  Vascularization Examples  Dentin  Blood Clot  Platelet Rich Plasma

Figure. Dentin secretion and odontoblast activity are related to gene and cascade pathway regulation. Simon S et al. ADR 2011;23: Copyright © by International & American Associations for Dental Research

So… What Regenerates?  Histologically?  Pulp-like tissue  Cementum-like tissue  Bone-like tissue How ?  Growth Factors - Proteins that binds to the cell and act as signals to induce intracellular proliferation and/or differentiation.

Growth Factors Examples found in the pulp: 1.Bone morphogenic protein 2.TGF-ß 3.FGF

Goal of Regenerative endodontics  Tooth is asymptomatic and functional Radiographic evaluation:  6-12 months  * Resolution of periapical radiolucency * May see increased dentinal wall thickness  months  * Increased dentinal wall thickness * Increased root length

Clinical Procedures

REFERENCES  Hargreaves, KM, Giesler T, Henry M., et al. Regeneration potential of the young permanent tooth: what does the future hold? J Endod 2008; 34:S51-6  Smith AJ, Scheven BA, Takahashi Y, et al. Dentine as a bioactive extracellular matrix. Arch Oral Biol 2012; 57:  Sun HH, Jin T, Yu Q, et al. Biological approaches toward dental pulp regeneration by tissue engineering. J. Tissue Eng. Regen. Med 2011; 5 e1-16.  Regeneration of tooth pulp and dentin : trends and advances Sarang Sharma1, Vimal Sikri2, Neel Kamal Sharma3, Vivek M. Sharma4  Sedgley CM, Botero TM. Dental stem sells and their sources. Dent Clin North Am 2012;56:  Bohl, KS, Shon J. Rutherford B. et al. Role of Synthetic Extracellular in development of engineered pulp. J. Biometer Sci. Polym Ed. 1998;9: