The document discusses regenerative endodontics, which aims to replace damaged tooth structures through biologically-based procedures. The key elements of regeneration are stem cells, growth factors, and scaffolds. Various stem cell types found in dental and other tissues are reviewed. Growth factors that promote stem cell differentiation are also discussed. The document provides details on the clinical protocol for regenerative endodontic therapy.

1. Regenerative
Endodontics
Ajo Babu George
IV BDS

2. CONTENTS
• Introduction
• Components of Regenerative Endodontics

3. INTRODUCTION
• Regenertive endodontics are biologically based procedures
designed to replace damaged structures ,including dentin and root
structures, as well as cells of pulp-dentin complex.
• Concept :Normal, sterile granulation tissue developed in the root
canal for revascularization will stimulate the cementoblasts/
undifferentiated mesenchymal cells (periapex) and lead to calcific
material formation at periapex or lateral dentinal walls.
• Goals :
 Primary goal- elimination of symptoms and the evidence of
bone healing.
 Secondary goal-increased root length or wall thickness.
 Tertiary goal-positive response to vitality tests.

4. COMPONENTS OF REGENATIVE ENDODONTICS
• The three key elements of tissue regeneration are:
 Stem cells
 Growth factors
 Scaffold

5. Stem cells
• According to Diogenes et al., regenerative procedures are all stem cell
based therapies.
• Stem cells are undifferentiated cells that are capable of differentiating
into various specialized cell types. They can be pluripotent or
multipotent in nature. They are located in stem cell niches.
• Types of stem cells:
 Dental pulp stem cells (DPSC)
 stem cells of the apical papilla (SCAP)
 Stem cells from human exfoliated deciduous teeth (SHED)
 Dental follicle stem cells (DFSC)
 Bone marrow stem cells (BMSC)
 Periodontal ligament stem cells (PDLSCs)
 Inflamed periapical progenitor cells (iPAPCs)
 Tooth germ progenitor cells (TGPCs)
 Salivary gland stem cells (SGSCs)

6.  Dental pulp stem cells
• stem cells derived from the dental pulp
• can form pulp like tissue , in future it is possible to
replace infected pulp tissue of a paining tooth with newly
generated pulp like tissue instead of doing RCT ,thus
preserving the vitality of the tooth
• It also has the ability to form bone that is useful for the
osseointegration of dental implants, thus increasing its
success rate .

7.  Stem cells of the apical papilla
• A unique population of dental stem cells known as stem cells
from the root apical papilla (SCAP) is located at the tips of
growing tooth roots . The apical papilla tissue is only present
during root development before the tooth erupts into the oral
cavity .
• SCAP have the capacity to differentiate into odontoblasts and
adipocytes .
• These cells are CD24+ but expression is down regulated upon
odontogenic differentiation in vitro coincident with alkaline
phosphatase up regulation.

8. Stem cells from human exfoliated deciduous teeth (SHED)
• Dental pulp of human exfolliated deciduous teeth
contains multipotent stem cells from human exfoliated
deciduous teeth (SHED). were identified to be a
population of highly proliferative, clonogenic cells
capable of differentiating into a variety of cell types
including neural cells, adipocytes, and odontoblasts.
Thus, exfoliated teeth may be an unexpected unique
resource for stem-cell therapies including autologous
stem-cell transplantation and tissue engineering.
• have higher rate of proliferation.
• have potential to form bone which is useful during
osseointegration of dental implants
• have the potential to repair calvarial defects in
immuno-compromised mice .

9. Dental follicle stem cells (DFSC)
• The dental follicle is a loose ectomesenchyme-derived
connective tissue sac surrounding the enamel organ and the
dental papilla of the developing tooth germ before eruption .
• It is believed to contain progenitors for cementoblasts,PDL and
osteoblasts.
• Dental follicle cells (DFC)form the PDL by differentiating into
PDL fibroblasts that secrete collagen and interact with fibers on
the surfaces of adjacent bone and cementum.
• Dental follicles contain progenitor cells which have the
capability of differentiating into cementum forming cells
(cementoblasts), osteoblasts of the alveolar bone, and
periodontal ligament fibroblasts.

10. Bone marrow stem cells (BMSC)
• Bone marrow-derived cells (BMDCs) have the potential to
engraft into several tissues after injury, but whether they can
become dental tissue-specific progenitor cells under normal
conditions and the relationship of these cells to the tissue-
resident cells are unknown
• Bone marrow progenitor cells communicate with dental
tissues and become tissue-specific mesenchymal progenitor
cells to maintain tissue homeostasis.

11. Periodontal ligament stem cells (PDLSCs)
• have potentials of regenerating typical cementum and
periodontal ligament like structure .
• tissue of the periodontium made by stem cell can be used
as a treatment modality to replace the
• diseased periodontium around teeth so as treatment to
mobility of teeth

12. • According to Hargreaves,stem cells like
SCAP,DPSCs,iPAPCs,PDLSCs,BMSCs are most commonly
used in regenerative endodontics.
• These cells have te capacity of differentiating into odontoblast-
like cells facilitating a progressive repopulation of the radicular
pulp space , promoting organized tissue repair ,angiogenesis
and reinnervation.

13. Growth factors
• Biological factors regulate stem cells to form the desirable cell
type.
• They promote the differentiation of mesenchymal stem cells
into odontoblast-like cells.
Platelet derived growth factors
Bone morphogenetic proteins (BMPs)
Transforming growth factor b
Vascular endothelial growth factor
Fibroblast growth factors
Insulin like growth factor
Nerve growth factor
Stromal cell derived growth factor I

14. BONE MORPHOGENETIC PROTEINS (BMPs)
• Comprises a subgroup of the superfamily TGF(Transforming
growth factor b) and are involved in cell proliferation,
differentiation and apoptosis.
• Have strong osteoinductive and chondrogenic effects.
• BMP2,BMP4,BMP7 &BMP11 invoved in mineralization.

15. Scaffold
• A scaffold provides a physiochemical and biological 3-D micro
environment for cell adhesion ,growth differentiation and
migration. It contains the growth factors.
• Functions :
 Supports cell organization and vascularization.
 Aids cell proliferation and differentiation.
 Contains nutrients,antibiotics for improved and faster
tissue development.
• Classification :-
 Natural – collagen,platelet rich plasma ,fibrin,
glycosaminoglycans
 Synthetic – polylactic acid ,polyglycolic acid ,polylactic-
co-glycolic acid

16. REVASCULARIZATION
• Revascularization, as defined by Andreasen, is a the
restoration of the vascularity to a tissue or organ.
• Mechanism of revascularization ,according to Shah N :
 Vital pulp cells at the apical end of root canal
proliferate into newly formed matrix and
odontoblasts, under the influence of HERS. Atubular
dentin is laid in the apical end and lateral aspects of
dentinal walls leading to apexogenesis and a thus
strengthening and reinforcement of root occurs.
 Multipotent dental pulp stem cells (immature
permanent teeth)from the apical end might be
seeded on to the existing dentinal walls and
differentiate into odontoblasts and deposit tertiary or
atubular dentin.

17.  Stem cells in the periodontal ligament can proliferate
and grow into the apical end and within the root canal
and hence deposit hard tissue at apex and lateral walls.-
cementum and Sharpey’s fibers in newly formed
tissues.
 Extensive proliferating property of SCAP & bone
marrow- instrumentation beyond confines of root –
bleeding –mesenchymal stem cell transplantation from
bone.

18. Regeneration of Dentin -Pulp complex
• Three strategies to regenerate dentin-pulp complex have been
proposed:
a. Regeneration of entire tooth.
b. Local regeneration of dentin-pulp complex from
amputed dental pulp.
c. Regeneration of dental pulp from apical dental pulp or
peri- apical tissues.
• Growth factors like bone morphogenetic proteins (BMPs) and
fibroblast growth factors(FGFs), stem cells and scaffolds are
essential for tissue engineering to regenerate tissues.
• Stem cells differentiate into specific cells for tissue defects ,
growth factors like BMPs ,induce proliferation of stem cells.
• Scaffolds with extracellular matrix properties support for cell
proliferation ,differentiation and tissue formation.

19. a) Regeneration of entire tooth
• Accepted as a model of organ replacement and regeneration
therapy.
• Tooth germ can be bioengineered using 3D organ germ culture
method in which dental epithelial and mesenchymal cells from
isolated tooth germs cultured in scaffolds ( synthetic polymers
–polylactic-co-glycolic acid ; bio ceramics- hydroxyapatite ,
tricalcium phosphate, calcium carbonate hydroxyappatite)

20. b) Local regeneration of dentin-pulp complex from
amputed dental pulp
• Induction of appropriate pulp wound healing and formation of
new dentin in dentin defects are essential in regeneration of
dentin-pulp complex.
• It was reported that BMP-2 with dentin powder induced
dentinogenesis in dentin cavity with pulp exposure.Here stem
or progenitor cells where induced from residual pulp through
the exposure site in the floor of the cavity.
• Ultrasound mediated delivery of growth differentiating factor -
11 (GDF-11) in dental pulp stem cells through sonoporation
induced reparative dentinogenesis

21. c) Regeneration of dental pulp from apical dental pulp
or peri- apical tissues
• Begins with identication of stem cells in the apical areas of
developing teeth in which root formation is incomplete.
• mesenchymal stem cells in apical papilla (SCAPs) differentiate
into odontoblast-like-cells that participate in pulp wound
healing and regeneration.
• Bone marrow derived mesenchymal stem cells (BMMSC) has
multipotent abilities and undergoes osteogenic differentiation.
• Periapical tissues include bone marrow and PDL which is the
source BMMSCs. Localization of SCAPs & BMMSCs in the
apical region --- induction for dentin-pulp complex regeneration

22. CLINICAL PROTOCOL REGENERATIVE ENDODONTICS
INDICATIONS
• Teeth with necrotic pulp and an immature apex.
• Pulp space not needed for post/core ,final restoration
• Patient compliance.
• No allergy to the medicaments to be used.
ROLE OF ANTIBIOTIC PASTE
• Antibiotic pastes are a combination of more than one antibiotic
mixed into a consistency of a paste.
• The triple antibiotic paste-commonly used-
ciprofloxacin,metronidazole, minocycline(1:1:1) in a
macrogol/propyleneglycol vehicle.
• Remains below CEJ and concentration is maintained to
0.1mg/ml and chamber is sealed with dentin bonding agents.

23. Local anesthesia, Isolation, access cavity preparation
Irrigation with 20ml of 1.5%NaOCl/5 min and saline rinse (20ml/
canal ,5min)
Drying with paper points
Placement of intracanal medicaments
Ca(OH)2 Low conc.triple antibiotic paste
Temp sealing with cavit/IRM/GIC
Recall patient after 1-4 weeks.
FIRST APPOINTMENT REGENERATIVE ENDODONTICS THERAPY

24. Assess response to initial treatment.
Signs of symptoms of
infections persists
No signs
/symptoms
Addtnl Rx time with
antimicrobial pastes
Alternative antimicrobials to
be considered
Local anesthesia (3%mepivacine without
vasoconstrictor)
Irrigation with 20ml of 17% EDTA,drying with paper points
Intracanal bleeding- k file 2mm past apical foramen
Blood in cavity till CEJ, 3-4 mm restorative material
Resorbable matrix over clot
White MTA(mineral trioxide aggregate)/
Ca(OH)2,capping –3-4mm GIC
SECOND APPOINTMENT –REGENERATIVE ENDODONTIC
THERAPY

25. FOLLOW --UP
• Clinical and radiographic examination
• No pain ,swelling or sinum tract formation.
• Resolution of periradicular radiolucency(6-12months of Rx)
• Increase in width of canal walls (12—24months of Rx)
• Increased root length
• Pulp vitality tests.

26. ADVANTAGES AND DISADVANTAGES
ADVANTAGES
• Achieve continued root development (root lengthening )and
strengthening due to enforcement of lateral dentin walls with
hard tissue deposition.
• Obturation of canal is not required.
• Splitting of root during lateral condensation avoided.
• After control of infection, completed in a single visit.
DISADVANTAGES
• Discoloration due to minocyclinein antibiotic paste.
• Prolonged treatment peroid compared with MTA apical barrier
technique.

27. POTENTIAL CAUSES OF FAILURE
• Poor root development.
• Insufficient bleeding during procedure.
• Pulp calcifications/obliterations.

28. CONCLUSION
• Regenerative endodontics holds promise of restoring pulp-
dentin complex in teeth with immature roots and necrotic
pulps.
• Procedure has advantages than traditional treatment of
increasing root wall thickness as well as root length while
maintaining immune competency.
• Significant scientific hurdles need to be overcome with
continued growth in knowledge and armamentarium.

29. REFERENCES
• Grossman’s endodontic practices-13th edition –Suresh
Chandra,V.Gopikrishna
• Regenerative Endodontics:regeneration or repair-
Stéphane R.J. Simon, DDS, PhD, Phillip L. Tomson PhD-
Journal of Endodontics.
• Regenerative Endodontics-Biological basis of
Regeneration of Dentin-Pulp Complex- Ariane Berdal,
PhD -Journal of Endodontics