2. INTRODUCTION
•Millions of teeth are saved each year by root canal
therapy. Although current treatment modalities offer
high levels of success for many conditions, an ideal form
of therapy might consist of regenerative approaches in
which diseased or necrotic pulp tissues are removed and
replaced with healthy pulp tissue to revitalize teeth.
•Regenerative endodontics is the creation and delivery of
tissues to replace diseased, missing, and traumatized
pulp.
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3. DEFINITION
•REGENERATIVE ENDODONTICS
•Regenerative endodontic procedures can be defined
as biologically based procedures designed to replace
damaged structures, including dentin and root
structures, as well as cells of the pulp-dentin complex.
•TISSUE ENGINEERING
•An interdisciplinary field that applies the principle of
engineering and life sciences towards the
development of biological substitutes that restore,
maintain, or improve tissue function.
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4. REVASCULARIZATION
•Revascularization as defined by ‘andreasen’ is the
restoration of the vascularity to a tissue or organ.
REPAIR
•Repair is the restoration of tissue continuity without
the loss of original architecture and function.
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5. OBJECTIVES
•The objectives of regenerative endodontic procedure,
are to:
•Regenerate pulp like tissue, ideally. The pulp -dentin
complex
•Regenerate resorbed root, cervical or apical dentin.
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6. GOALS
• Primary goal (essential): The elimination of
symptoms and the evidence of bony healing.
• Secondary goal (desirable): Increased root wall
thickness and/or increased root length.
• Tertiary goal: positive response to vitality
testing.
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8. STEM CELLS
•A stem cell is defined as ‘‘ A
cell that has the ability to
continuously divide and
produce progeny cells that
differentiate into various
other types of cells or
tissues.
8
9. All stem cells regardless of their source have three
general properties:
1. Capable of dividing and renewing themselves for
long periods
2. Unspecialized
3. May give rise to specialized cell types
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10. CLASSIFICATION
Depending on the ability of the stem cells to produce the
different types of cells they are classified into pluripotent
or multipotent.
• Pluripotent stem cells are those which are capable of
differentiating into specialized cells of any three germ
layers. Truly pluripotent stem cells are found in the
developing embryos.
• Stem cells, found in adults are restricted in their capacity
to differentiate and are thus termed multipotent. The
mesenchymal tissues (e.g. bone, dental pulp, periodontal
ligament) appear to have an enriched population of adult
stem cells 10
11. •Stem cells are classified as embryonic/fetal and
postnatal/ adult stem cell.
•Embryonic stem cells derived from inner cell mass of
early embryo called blastocyst & are capable of
dividing and renewing themselves for long periods
without differentiating whereas adult stem cell
cannot. Eg: hematopoietic cell & hepatic cell etc.
• post natal cells taken from mature tissue. They are
lineage restricted & are referred to by their tissue of
origin. Its play an important role in local tissue repair
and regeneration. Eg: dental pulp stem cell
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12. • Most stem cells in the oral region are of mesenchymal
origin. It is this multipotent capacity of the mesenchymal
stem cells which forms the basis of all regenerative
endodontic procedures .
Oral stems cells come under the post natal stem cell
category and includes
• Stem cells of the apical papilla (SCAP)
• Dental pulp stem cells (DPSCs)
• Inflamed periapical progenitor cells (iPAPCs)
• Periodontal ligament stem cells (PDLSCs)
• Bone marrow stem cells (BMSCs)
• Stem cells from human exfoliated deciduous teeth
(SHED)
• Tooth germ progenitor cells (TGPCs)
• Dental follicle stem cells (DFSCs)
• Salivary gland stem cells (SGSCs)
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J Istanbul Univ Fac Dent 2017;51(3 Suppl 1):S41-S51.
13. Schematic representation of the potential sources of postnatal stem cells in the oral
environment. Cell types include tooth germ progenitor cells (TGPCs), dental follicle
stem cells (DFSCs), salivary gland stem cells (SGSCs), stem cells of the apical papilla
(SCAP), dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous
teeth (SHED), periodontal ligament stem cells (PDLSCs), inflamed periapical progenitor
cells (iPAPCs) and bone marrow stem cells (BMSCs).
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14. •Stem cells are often categorized by their source: The
most practical clinical application of a stem cell
therapy would be to use a patient’s own donor cells.
•Autologous stem cells are obtained from the same
individual to whom they will be implanted.
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15. Stem cells could be taken from the
•bone marrow
•peripheral blood
•fat removed by liposuction
•the periodontal ligament
•oral mucosa, or skin.
An example of an autologous cell bank is one that
stores umbilical cord stem cells.
•It may be possible to use neuronal stem cells from
adipose fat as part of regenerative medicine instead of
bone marrow cells, possibly providing a less painful
and less threatening alternative collection method.
15
Seo BM, Miura M, Sonoyama W, Coppe C, Stanyon R, Shi S. Recovery of stem cells from
cryopreserved periodontal ligament. J Dent Res 2005;84:907–12.
16. •One potential disadvantage of harvesting cells from
patients is that surgical operations might lead to
postoperative sequelae, such as donor site infection.
•To accomplish endodontic regeneration, the most
promising cells are autologous postnatal stem cells,
because these appear to have the fewest
disadvantages that would prevent them from being
used clinically.
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17. GROWTH FACTORS
•Growth factors are proteins that bind to receptors on
the cell and induce cellular proliferation and/or
differentiation.
• Growth factors play a role in signalling many
events in pulp dentine regeneration. Two
important families of growth factor that play a
vital role are transforming growth factor (TGF)
and bone morphogenetic protein (BMP).
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21. • Fibroblast growth factors(FGF) are for general
growth-promoting effects on most fibroblastic cells:
it stimulates angiogenesis & cell migration in vivo.
• Platlet derived growth factor (PDGF) are derived
from platlets & endothelial cells: promotes
connective tissue cells.
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22. SCAFFOLDS
•A scaffold is an artificial three-dimentional frame
structure that serves as a mimic of extracellular matrix
for cellular adhesion, migration, proliferation, and
tissue regeneration.
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26. PLATLET RICH PLASMA(PRP)
•PRP is being established as a potentially ideal scaffold
for regenerative endodontic treatment regimen.
•PRP contains growth factors, stimulates collagen
production, recruits other cells to the site of injury,
produces anti-inflammatory agents & intiates vascular
ingrowth.
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27. • Blood sample from the patient’s arm(30 ml
approximately)
• Centrifuging the blood in the presence of an
anti-coagulant removal of erythrocytes from
the blood
• Then adding thrombin and calcium for
coagulation of prepared PRP then injected to
canal space
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Preparation of PRP
#The first spin is at 2400 rpm for 10 minutes. With this spin we
separate the erythrocytes from platelet poor plasma. With the
second spin at 3600 rpm for 15 minutes we separate
the PRP from platelet poor plasma
29. PLATLET RICH FIBRIN
•Platelet-rich fibrin (PRF), introduced by Choukroun in
2001, is one of the most commonly used (autologous
fibrin matrix) scaffolds in regenerative endodontic
procedures
•It is rich in pre-existing growth factors like PDGF, TGF-ß
etc., which helps in migration of fibroblasts and
endothelial cells.
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30. Preparation of PRF
• PRF is prepared by collecting venous
blood from the patient’s arm without
anticoagulant.
• The blood is immediately centrifuged
at a speed of 3000 rpm for 10 mins.
• The resultant product consists of PRF
clot in the middle and RBC at the
bottom.
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32. COLLAGEN
•It constitutes the extracellular matrix of all the tissues
& is responsible for the tensile strength of the tissues.
Advantages:
•Biocompatibility & biodegradability
•High alkaline phosphatase activity.
•Easy placement of cells & growth factors along with the
easy replacement with natural tissues after its
degradation.
•Collagen forms the hard and soft tissue which
stimulates the natural extracellular matrix of dentine
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33. when used for REPs.
•Its available in various forms via
gels, sponges and sheets.
Disadvantage
•Rapid degradation and contraction
are the undesirable properties of
collagen
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34. CHITOSAN
•Produced commercially by deacetylation of chitin,
which is a structural element in exoskeleton of
crustaceans (Crabs & Shrimps).
•Ability of chitosan to form porous scaffold makes it is
to be used in REPs.
•Advantages –
•Biocompatible, Easily absorbable,
•Antibacterial activity, increases alkaline phosphate
activity, shows fibroblast & odontoblastic
proliferation.
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36. GLYCOSAMINOGLYCANS
•Hyaluronic acid – One of the glycosaminoglycans in
ECM & plays an important role in maintaining
morphologic organization by preserving extracellular
spaces.
•It is bioactive and has properties of osteogenesis and
chondrogenesis. When used for REPs it can even
promote odontogenesis by forming pulp-dentin
complex.
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37. DEMINERALIZED DENTIN MATRIX
•The organic matrix of dentin consist of 18% collagen, 2%
noncollagenous proteins (NCPs), 70% hydroxyapatite
(HA), and 10% body fluid (percentages indicating
weight/volume). Their matrix is a repository for growth
factors, such as bone morphogenetic proteins (BMPs),
transforming growth factor-β, insulin-like growth factor,
and basic fibroblast growth factor.
37
38. Advantages:
•Non-immunogenic and mechanically superior
•It shows direct induction of differentiating
odontoblast-like cells and indirect matrix synthesis
leading to odontoblast differentiation
Disadvantage:
•Tooth demineralization is time consuming (usually 2–6
days).Drawback of demineralization is that prolonged
acid exposure may negatively affect non-collagenous
proteins involved in new bone formation
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39. ARTIFICIAL SCAFFOLDS
•Polymers with controlled physicochemical features
such as degradation rate, microstructure, and
mechanical strength. For eg:
•Polylactic acid , polyglycolic acid , and their
copolymers-poly lactic-co-glycolic acid etc.
•Synthetic hydrogels include polyethylene glycol based
polymers.
•Scaffolds modified with cell surface adhesion peptides
such as arginine, glycin & aspartic acid to improve cell
adhesion and matrix synthesis within the 3D network
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40. •Scaffolds containing inorganic compounds such as
hydroxyapatite (HA), tricalcium phosphate (TCP) and
calcium polyphosphate (CPP), are used to enhance
bone conductivity.
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41. AN OVERVIEW OF POTENTIAL TECHNOLOGIES FOR
REGENERATIVE ENDODONTICS
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42. REVASCULARIZATION
•Revascularization can be broadly defined as the
restoration of vascularity of a tissue or organ.
•The authors stated that the term revascularization
does not completely address the desired outcomes of
regenerative endodontic procedures, because the
desired outcome is regeneration of the pulp-dentin
complex.
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43. MECHANISM
The process of revascularization takes place are as follows:
• A few vital pulp cells remaining at the apical end of the root canal might
proliferate into the newly formed matrix and differentiate into
odontoblasts.
• Continued root development could be due to multipotent dental pulp stem
cells, which are present abundantly in immature permanent teeth
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44. •Stem cells in the periodontal ligament can proliferate
and grow into the apical end and within the root
canal.
•The fourth possible mechanism of root development
could be attributed to SCAP or to the bone marrow.
•Instrumentation beyond the confines of the root canal
to induce bleeding can also transplant mesenchymal
stem cells from the bone into the canal lumen.
•The blood clot is a rich source of growth factors such
as platelet-derived growth factor, vascular endothelial
growth factor, platelet derived epithelial growth
factor, and tissue growth factor.
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45. WHAT ARE THE CONSIDERATIONS FOR
CLINICAL REGENERATIVE ENDODONTIC
PROCEDURES
• Various regenerative endodontic treatment protocols have been
associated with a successful clinical outcome and currently there is no
single recommended protocol.
• Common features of cases with successful clinical outcomes after REPs
are:
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
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46. REVASCULARIZATION PROTOCOL
46
the ultimate goal of this approach is to develop a tissue
engineering–based method of pulpal regeneration in the fully
developed permanent tooth
Informed consent issues should include the number of appointments
(at least two), the possible adverse effects (primarily potential
minocycline staining of the crown), the potential lack of response to
treatment and alternative treatments, and possible post treatment
symptoms.
Clinical staining of the crown and any root structure above the
gingival margin appears to be due to the presence of minocycline.
This can be minimized by using a delivery system that restricts the
drug below the cementoenamel junction (CEJ).
Cohen 11th edition pg-467
47. First appointment
47
Following informed consent, the tooth is anesthetized, isolated, and
accessed
Minimal instrumentation should be accomplished, but the use of a
small file to “scout” the root canal system and determine working
length is important.
The root canal system is copiously and slowly irrigated with 20 ml of
NaOCl for 5 min followed by 20 ml of 0.12% to 2% chlorhexidine
(CHX).
It is important to place the needle into the apical third and irrigate
using needles with a closed end and side-port vents (e.g., Max-I-
Probe needles), together with a slow rate of infusion, to help to
reduce any irrigants passing through the open apex.
Cohen 11th edition pg-467
48. The root canal system is then dried with sterile paper points, and
the antimicrobial medicament is delivered into the root canal space.
Calcium hydroxide or an antibiotic paste or solution (1mg/ml) is
delivered to canal system. Access is temporarily restored
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49. Second appointment
•The patient is evaluated for resolution of any signs or
symptoms of an acute infection (e.g., swelling, sinus
tract pain, etc.)
•The antimicrobial treatment is repeated if resolution
has not occurred.
•Since revascularization-induced bleeding will be
evoked at this appointment, the tooth should not be
anesthetized with a local anesthetic containing a
vasoconstrictor.
•Instead, 3% mepivacaine can be used, which will
facilitate the ability to trigger bleeding into the root
canal system
49
50. •Following isolation and reestablishment of coronal
access, the intracanal medicament is removed by
irrigating with 17% EDTA(30ml/canal, 5 min)& then
final flush with saline(5ml/canal, 1 min).
•The canals are dried with paper points.
•Bleeding is induced by rotating a precurved k-file size
#25 at 2mm past the apical foramen with the goal of
having the whole canal filled with blood to the level of
the CEJ.
•Once a blood clot is formed, a premeasured piece of
collaplug is carefully placed on the top of the blood
clot to serve as an internal marix for the placement of
apporoximately 3mm white MTA or biodentin.
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51. •A layer of GIC is flowed gently over the bioactive coronal
barrier and light cured for 40 sec. Then composite resin
restoration is placed over the GIC.
•A 12- to 18-month recall should be considered as the
earliest time point to conduct the clinical examination
and evaluate continued radiographic improvement in
root development
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53. A COMPARISON BETWEEN REVASCULARIZATION
ENDODONTIC TREATMENT AND OTHER PULP
TREATMENT PROCEDURES
•There are several procedures designed to treat the
incompletely formed root that occur following
endodontic procedures.
•Apexification is defined as a method to induce a
calcified barrier in a root with an open apex or the
continued apical development of an incompletely
formed root in teeth with necrotic pulp tissue.
•This is distinct from revascularization, since
apexification does not attempt to regain vital tissue in
the canal space.
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54. • The outcome of an apexification procedure is
establishment of an apical barrier against which an
obturating material may be placed.
• A second term, apexogenesis, is defined as a vital pulp
therapy procedure performed to encourage continued
physiologic development and formation of the root end.
• An important distinction is that apexogenesis is indicated
for teeth in which there has been no loss of vascularity,
thus no need to “revascularize” the canal space. (Cohen)
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55. •In apexification with Ca(OH)2 :
1. Chances of root fracture and stem cell toxicity.
2. At least 6 months are required to create an apical
barrier, and multitple visits are needed to replenish
calcium hydroxide.
55
Andreasen JO, Farik B, Munksgaard EC. Long-term calcium hydroxide as a root canal dressing may increase risk of root
fracture. Dent Traumatol. 2002;18:134–137.
56. •MTA is used in the one or two step apexification
procedure, and therefore a fewer number of
appointments are needed.
•In spite of this, apexification with MTA neither
strengthens the root nor induces further root
development.
•As a result, the roots remain thin and fragile, and hence
another treatment approach is needed
56
Bose R, Nummikoski P, Hargreaves K. A retrospective evaluation of radiographic outcomes in immature teeth with necrotic root canal systems
treated with regenerative endodontic procedures. J Endod. 2009;35:1343–1349.
57. THE PERCENTAGE INCREASE IN ROOT WIDTH
AND ROOT LENGTH AFTER THE TREATMENT
PROCEDURE
57
Jeeruphan T, Jantarat J, Yanpiset K, Suwannapan L, Khewsawai P, Hargreaves KM. Mahidol study 1: comparison of radiographic
and survival outcomes of immature teeth treated with either regenerative endodontic or apexification methods: a retrospective
study. J Endod.2012;38:1330–1336.
58. MEDICAMENTS BEING USED IN
CASES OF REVASCULARIZATION
1.Triple antibiotic paste (1 : 1 : 1 mixture of
ciprofloxacin/metronidazole/minocycline)
2. Ca(OH)2 alone or with an antibiotic paste.
3. Formocresol
58
Bin-Na Lee, Jong-Wook Moon, ‘A review on regenerative endodontic treatment procedure’Restor Dent Endod. 2015 Aug; 40(3):
179–187
59. 1.The triple antibiotic paste produced significantly greater differences in
dentinal wall thickness compared with either the Ca(OH)2 or
formocresol groups.
2.The formocresol group showed the smallest improvement in root length
and thickness.
3.Location of Ca(OH)2 placement appeared to be a strong predictor of
radiographic outcome.
4. When Ca(OH)2 placement was restricted to the coronal
half of the root canal, the increase in root wall thickness
was 55%, compared to a 3% increase when it was placed in the apical
half of the root canal system. This might be due to residual Ca(OH)2
having a cytotoxic interaction with stem cells
59
Bose R, Nummikoski P, Hargreaves K: A retrospective evaluation of radiographic outcomes in immature teeth with necrotic root
canal systems treated with regenerative endodontic procedures. J Endod 35:1343, 2009.
60. •ROLE OF ANTIBIOTIC PASTE
•The success of the regenerative endodontic procedure
depends on the effective disinfection of the canal.
•Antibiotic pastes are a combination of more than one
antibiotic mixed into a consistency of a paste.
•They are advocated as an effective alternative to
calcium hydroxide that has been traditionally used for
intracanal disinfection
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61. CLINICAL MEASURES OF
TREATMENT OUTCOME
•For revascularization not only radiographic evidence
of periradicular health but also radiographic and other
clinical evidence of functioning vital tissue in the canal
space.
•Radiographic evidence of functioning pulp (or pulp
like) tissue would include continued root growth, both
in length and wall thickness
•Other measures of the presence of vital, functioning
tissue in the canal space include laser Doppler blood
flowmetry, pulp testing involving heat, cold, and lack
of signs or symptoms.
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62. •The ideal clinical outcome is an asymptomatic tooth
that does not require retreatment, but to validate that
regenerative endodontic techniques are truly
effective, non subjective vitality-assessment methods
are essential”
62
63. ADVANTAGES
• Achieving continued root development (root
lengthening) and strengthening due to reinforcement of
lateral dentinal walls with deposition of new dentin/
hard tissue are the biggest advantages.
•Obturation of the canal is not required unlike in calcium
hydroxide–induced apexification (inherent danger of
splitting the root during lateral condensation can be
avoided).
•After control of infection, the procedure can be
completed in a single visit
63
64. DISADVANTAGES
•Discoloration due to use of minocycline in triple
antibiotic paste (revealed by Kim et al.)
•Prolonged treatment period and more appointments
(compared with one-visit MTA apical barrier
technique)
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65. •POTENTIAL CAUSES OF FAILURE
•Poor root development (absence of increase in root
length, absence of increase in root wall thickness, or
lack of formation of tooth apex)
•Insufficient bleeding during the procedure
•Root canal calcification/obliteration
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