FACTORS
AFFECTING PERIODONTAL BONE REPAIR
Najam-us-Sahar
Abstract
Background: Bone graft,
Chitosan and Bone Marphogenetic Protein-2 are selected among different
factors affecting or elicit the bone regeneration. These factors have been evaluated
by many researchers. The properties and limitation of these factors are
discussed in this article.
Objective: To compile and analyze various published research
results related to Periodontal Bone Repair.
Study design: Analytical and comparative study
Methods: Reviewed most of the research articles related to the Periodontal
Bone Repair. Categorize the factors
or materials that enhance the efficacy of the regeneration of periodontal bone.
Conclusion: Many researches have been conducted for evaluation of
Bone regeneration. Latest techniques
with different materials should be practiced to speed up the bone repair
process.
 |
INTRODUCTION
Bone is an integral part of the human body that forms
a framework which is attached to the
muscular system. Bone has ability to rebuild itself after getting damaged. It
has a natural process of healing through Osteons. The Osteons are formed when
bone gets injured. It is a tough
supporting structure that always undergoes the process of remodeling. For interpreting
the basic concept of healing, it is indispensable to see the Pathophysiology of bone defects.
The bone defect is formed when bone gets insulted or
hurt. The gap is brought out at the lieu
of injury, filled with necrotic bone debris, blood from broken blood vessel and
inflammatory cells. Cells and signals combined to act on the necrotic debris to
remove and then create new bone by forming scaffold for the new
generating bone.
Bone Structure
|
Ratio of both bones
|
% of remodeling (per year)
|
Cortical Bone
|
9
|
3%
|
Cancellous Bone
|
1
|
30%
|
All Human Body Bones
|
6%
|
Periodontal bone defects are usually caused by trauma,
fracture, surgery, tumor, Periodontitis, Osteoporosis and Arthritis. The most
common cause of periodontal bone defect is Periodontits – the inflammation of Periodontium, which leads
to the underneath bone loss.
Natural remodeling process in human bones:
As remodeling occurs, Osteoblastic cells produced new bone cells and Osteoclastic bone cells
destroyed or resorbed existing bone. This formation and resorption process
called Remodeling. Failure in maintaining the balance of remodeling results in
multiple problems like Osteoporosis and Arthiritus.
Bone regeneration
techniques and materials
With the help of different materials, Periodontal bone
can be regenerated through different techniques.
Bone Grafting
Bone grafting is the replacement of injured bone by
some substituting material. It can be natural as well as synthetic. There are
three kinds of bone grafting materials – Osteogenesis, Osteoinduction and
Osteoconduction. The bone formation originates from the cell or tissue, which
is contained in Osteogenisis material. The protein or growth factor that
effects on proliferation and differentiation progenitor cells (that present in
clot or granulation tissue) forms a new bone. The growth and replacement of new
bone occur with the help of Osteoconductive material which forms scaffold for
the new bone.
Bone grafting materials
|
Function
|
Osteogenisis
|
Helps in
Bone formation
|
Osteoindution
|
Proliferation
and differentiation of proginator cells
|
Osteoconductive
|
Replacement
of new bone by making scaffold
|
Properties
of Ideal Bone Grafting Material
Bone grafting material has to be Biocompatible, safe, non-toxic,
non-allergic and should contain no risk of disease transmission. Its
composition and particles should be alike to human bone and also have space maintaing capability. The resorption
rate should also be similar to human bone.
Types of
Bone Grafting
Autogenes: This type of bone graft comes from the same individual.
It is called “Gold Standard”, that satisfies all the requirements of ideal
grafting material.
Allogenic: This type of bone graft comes from the different
individual of the same specie.
Xenogenic: This type of bone graft comes from some other species,
i.e. cow, horse etc.
Alloplastic
or Synthetic: This is
the type of bone graft made up with different formulation of Calcium and Phosphate.
Limitation
Of Bone Graft
Bone substituting materials for bone grafting have
been used with good clinical efficacy, but it has some limitation like bone
resorption, low biodegradability, poor adaptation and immune response. They work
only on the physical scaffold for bone tissues. These materials may
require several months or years to form
new bone.
Effects of Chitosan
on Periodontal Bone Repair
Chitosan
is the derivative polymer which is made
by deactylation
of Chitin. Chitin is mainly present in exoskeleton of Crutaceans and in some Fungi.
The properties of Chitosan include high Osteoinductivity, Osteointegratability, easy application and gradual biodegradability. These qualities make Chitosan a good material for bone regeneration. Chitosan is a biodegradable and biocompatible substance.
The minimal inflammatory reaction is also
observed when Chitosan coated pins are in contact. It is also used in
biochemical coating for Orthopedics and Crainiofacial implants. The Vascularization
of blood vessels is increased with Chitosan. It increases the activity of Osteoblasts
that leads to bone formation and also can increase Osteogenesis. It also helps
in the proliferation of Osteoblastic cells. Kim and co-workers studies found
that Chitosan can also work on tissue engineering such as it forms skin, bone and cartilage. The present studies also
reveal the effect on bone regeneration. Zhang and his co-workers, research
found Chitosan as a Biocompatible and Biodegradable Polymer, if used with Mannitol
and Calcium Phosphate cements for bone healin . It can be used for shaping Hydroxyapatite
in surgeries and implants. They also used Tetra Calcium Phosphate with Chitosan
to form non-rigid and strong Calcium Phosphate Cement that used in repairing of
periodontal tissues and bone surrounding implants. Bumgardner and co-workers
also revealed that Chitosan is a Biopolymer that elicit the procedure of bone
formation, facilitates the healing procedure and has Tri-microbial properties.
Ma and Co-workers reported that Chitosan Thermosensitive
Hydrogel rhBMP-2 facilitates regeneration of the periodontal tissues. Chitosan Hydrogel
is used by injecting in the lesion . As their study revealed, it is not only helped in bone regeneration, it
also maintained the bone density.
Zhang and co-workers used Chitosan
scaffold for the regeneration of Alvealar bone in dental implants. They found Chitosan
scaffold can also be used in bone regeneration. Chitosan is considered a good
alternative of bone graft. It also improved the bone regeneration of
periodontal bone loss.
Chitosan is poorly soluble in water or any oraganic
solvent; limiting its uses. Another
limitation of Chitosan is its higher degree of swelling in aqueous environment.
Recombinant
human bone Morphogenetic Protein-2 stimulated Priodontal bone regeneration
Recombinant human bone Morphogenetic Protein-2
consist of Fibronectin and other Glycoproteins. Urist and his co-workers
studied revealed that when untreated decalcified bone matrix is implanted in muscular pouch, the formation of
cartilage and bone is stimulated.
Bone Morphogentic Protein-2 sequestered in
a decalcified bone matrix, responsible for the induction of new bone. Bone Morphogenetic
Protein-2 is evaluated in Mandibular and
Cleft Palate reconstruction, Sub Antral, Alveolar Augmentation, Dental Implant Fixation
and Periodontal Indication.
It is also
observed, the Ankylosis of the tooth with the newly formed bone.
Ankylosis is evaluated to compromise healing. This limits the uses in flexible
gross architecture.
METHODOLOGY
The
literature search for this article were based on research papers. Most of research papers were about bone regeneration and selected three factors,
bone graft, Chitosan and Bone Morphogenetic Protein-2, for comparison. The
selection criteria are based on the
usage, properties of material,
researcher’s recommendation and better evaluation of the
material. The bibliography of the selected research papers is also included in the
review as additional reference.
DISCUSSION
Bone Graft has been used commercially, in spite of its
limitations like deficiency to achieve ideal bone properties. It also needs
surgery to implant graft and suffered with postoperative complication and
infection transmission, etc. Although it posses significant clinical efficacy. Chitosan
has Biocompatible and Anti-Microbial
properties. It is used commercially in different drugs. The uses are limited
due to poor solubility in water and it swells up in Aquous medium. After long efforts
of several researchers, Bone Morphogenic
Protein is now available commercially. There are some hurdles like, how to
deliver the molecules in fashion to obtain consistent bone formation. It was observed that Bone Morphigenic Protein
rapidly cleared from the surgical site, thus need a carrier which can maintain the
Protein molecule at the surgical site and act as a scaffold for new bone.
CONCLUSION
The significant research has been conducted about Bone
Grafting, Chitosan and Bone Morphogenic Protein. It is
concluded that these factors are useful to elicit bone repair. After many researches, these materials are now
available commercially. However, this is
more important that the gross number of patients can get benefit from
these materials.
