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New Mexico Dental Journal, Spring 2015
6
Pulpal Regeneration
T
he treatment of immature permanent teeth with pulpal
necrosis is a common endodontic problem that can
be very challenging for many reasons. The root canal
system can be difficult to debride and the thin dentinal walls
are at an increased risk of cervical fracture (7). This can result
in a restorative problem, since dental implants are generally
not indicated in young patients who are still developing (1).
This problem often presents itself as the result of trauma to
developing incisors, or perhaps deep caries in newly erupted
molars. With a population that has an ever-increasing life span,
as well as an increased desire to retain their natural dentition,
our patients are counting on us to provide treatment that can
hopefully last for decades!
For many years, the treatment of choice for the immature,
necrotic tooth has been a traditional apexification procedure
using calcium hydroxide or the use of apical barriers such as
MTA. The underlying goal of these treatment modalities has
been to seal the apex of the tooth and hopefully allow for
resolution of an apical lesion. Typically, the success rate of
these apexification procedures is high (usually reported to be
greater than a 90% success rate).
However, the most glaring problem with any type of apexifica-
tion procedure is that there is no continued growth of the root
wall, thus leaving a tooth in a weakened state and more prone
to fracture. These apexification procedures can also be very
time-consuming and technique sensitive.
In 2004, researchers first published a case report describing
a new treatment modality for the management of immature,
necrotic permanent teeth called “revascularization”. The treat-
ment protocol differed from traditional apexification proce-
dures and allowed for the continued development of the root
and surrounding tissue instead of simply creating an apical
barrier (2).
Now referred to as Regenerative Endodontics or Pulpal Regen-
eration, many case studies and multiple articles related to this
topic have since been published in endodontic journals around
the world.
From the AAE’s Colleagues for Excellence Spring 2013 Issue
on Regenerative Endodontics we read that “Regenerative
endodontic therapy provides an alternative treatment approach
that builds on principles of regenerative medicine and tissue
engineering.
The aim of the therapy is to successfully treat these challenging
cases by regenerating functional tissue utilizing protocols
referred to as regenerative endodontic procedures (REPs)” (1).
The ultimate goal of regenerative therapy in the immature
necrotic tooth is to replace damaged structures such as dentin,
cementum and bone, as well as cells of the pulp-dentin
complex (3).
There are three major components of tissue
engineering to be considered in pulpal regeneration:
1)
Stem Cells
. Several types of stem cells have been
isolated from teeth including DPSCs (dental pulp
stem cells), PDLSCs (periodontal ligament stem cells),
SCAPs (stem cells from apical papilla) and DFPCs
(Dental follicle progenitor stem cells).
2)
Scaffolds
. These components “provide support for cell
organization, proliferation, differentiation and vascu-
larization (4)”. Pulpal regenerative procedures have
investigated the use of scaffolds such as dentin, blood
clots, platelet-rich plasma as well as certain types of
natural and synthetic scaffolds (1).
3)
Growth Factors
. “Growth factors are proteins that
bind to receptors on the cell and act as signals to
induce cellular proliferation and/or differentiation”
(3). “Recent studies have shown that dentin contains
a number of bioactive molecules that, when released,
play an important role in regenerative procedures”
(1), (5, 6).
Endodontists are now using their knowledge of pulp biology,
dental trauma and tissue engineering to deliver a biologically-
based treatment which can allow for continued root develop-
ment, increased dentinal wall thickness, and apical closure
to restore the root canal system to a healthy state in necrotic,
immature teeth.
By Ryan Savage, DDS
continues