Regenerative techniques for periodontal therapy

1. Dr. Enas Elgendy
Ass. Prof of Periodontology

3. 1- Graft Materials and Procedures
• Numerous therapeutic grafting modalities for restoring
periodontal osseous defects have been investigated. Material
to be grafted can be obtained from the same individual
(autografts), from a different individual of the same species
(allografts), or from a different species (xenografts).
• Bone graft materials are generally evaluated based on their
osteogenic, osteoinductive, or osteoconductive potential.
1- Osteogenesis refers to the formation or development of new
bone by cells contained in the graft.
2- Osteoinduction is a chemical process by which molecules
contained in the graft (bone morphogenetic proteins) convert
the neighboring cells into osteoblasts, which in turn form bone.
3- Osteoconduction is a physical effect by which the matrix of
the graft forms a scaffold that favours outside cells to penetrate
the graft and form new bone.

4. • Periodontal defects as sites for transplantation differ from
osseous cavities surrounded by bony walls. Saliva and
bacteria may easily penetrate along the root surface, and
epithelial cells may proliferate into the defect, resulting in
contamination and possible exfoliation of the grafts.
Therefore the principles established to govern
transplantation of bone or other materials into closed
osseous cavities are not fully applicable to transplantation of
bone into periodontal defects.
• All grafting techniques require presurgical scaling, occlusal
adjustment as needed, and exposure of the defect with a full-
thickness flap. The flap technique best suited for grafting
purposes is the papilla preservation flap because it provides
complete coverage of the interdental area after suturing.
The use of antibiotics after the procedure is generally
recommended.

5. Classification of Grafts
1- Autogenous Grafts (Autografts)
Extra oral.
Intra oral.
2- Allogenic Grafts (Allografts)
Freeze dried bone Allografts (FDBA).
Demineralized freeze dried bone allografts (DFDBA).
3- Bone Substitutes
Xenogenic graft (Xenografts)
- Bovine derived hydroxyapatite.
Alloplastic grafts (Alloplasts)
- Bioceramics.
Tricalcium phosphate.
Hydroxyapatite.
- Polymers
Hard tissue replacement (HTR) polymer.
- Bioactive glasses.

6. Autogenous Bone Grafts
Bone from Intraoral Sites
• Sources of bone include bone from
1- healing extraction wounds,
2- bone from edentulous ridges,
3- bone trephined from within the jaw without damaging the roots,
4- newly formed bone in wounds especially created for the purpose,
5- bone removed during osteoplasty and ostectomy.

7. Autogenous Bone Grafts
Sources of the graft material include
 the lingual ridge on the mandible,
 exostoses, edentulous ridges,
 the bone distal to a terminal tooth,
 bone removed by osteoplasty or ostectomy,
 the lingual surface of the mandible and maxilla at least 5 mm from the roots.
Bone is removed with a carbide bur #6 or #8 at speeds between 5000 and
30,000 rpm, placed in a sterile dappen dish or amalgam cloth, and used to fill

8. Allografts
• Bone allografts are commercially available from
tissue banks. They are obtained from cortical bone
within 12 hours of the death of the donor, defatted,
cut in pieces, washed in absolute alcohol, and deep-
frozen. The material may then be demineralized, and
subsequently ground and sieved to a particle size of
250 to 750μm and freeze-dried. Finally, it is vacuum-
sealed in glass vials.
• Freeze dried bone Allografts (FDBA).
• Demineralized freeze dried bone allografts
(DFDBA).

9. Xenograft
• Currently, an anorganic, bovine-derived bone marketed under the
brand name Bio-Oss (OsteoHealth) has been successfully used both
for periodontal defects and in implant surgery. It is an
osteoconductive, porous bone mineral matrix from bovine
cancellous or cortical bone. The organic components of the bone are
removed, but the trabecular architecture and porosity are retained.
The physical features permit clot stabilization and revascularization
to allow for migration of osteoblasts, leading to osteogenesis. Bio-
Oss is biocompatible with the adjacent tissues, eliciting no systemic
immune response.

10. Non-bone Graft Materials
• In addition to bone graft materials, many nonbone graft
materials have been tried for restoration of the periodontium.
These include:
1- sclera,
2- dura,
3- cartilage,
4- cementum,
5- dentin,
6- plaster of Paris,
7- plastic materials,
8- ceramics,
9- coral-derived materials.

11. Calcium Phosphate Biomaterials
Calcium phosphate biomaterials have excellent tissue
compatibility and do not elicit any inflammation or foreign body
response. These materials are osteoconductive, not
osteoinductive, meaning that they will induce bone formation
when placed next to viable bone but not when surrounded by
non-bone-forming tissue such as skin.
Two types of calcium phosphate ceramics have been used, as
follows:
• Hydroxyapatite (HA) has a calcium-to-phosphate ratio of 1.67
(8:5), similar to that found in bone material. HA is generally
nonbioresorbable.
• Tricalcium phosphate (TCP), with a calcium-to-phosphate
ratio of 1.5, is mineralogically B-whitlockite. TCP is at least
partially bioresorbable.

12. Bioactive Glass
• Bioactive glass consists of sodium and calcium salts,
phosphates, and silicon dioxide; for its dental applications, it is
used in the form of irregular particles measuring 90 to 170μm
(PerioGlas)
• When this material comes into contact with tissue fluids, the
surface of the particles becomes coated with
hydroxycarbonate apatite, incorporates organic ground
proteins such as chondroitin sulfate and glycosaminoglycans,
and attracts osteoblasts that rapidly form bone. These
bioactive glass materials also appear to be encapsulated by
collagen.

13. Coral-Derived Materials
• Two different coralline materials have been used in clinical
periodontics:
1- natural coral
2- coral-derived porous hydroxyapatite.
Both are biocompatible, but whereas natural coral is resorbed
slowly (several months), porous hydroxyapatite is not resorbed
or takes years for resorption.

15. II- Guided tissue regeneration
1- Principles of GTR
 GTR is a term used to define procedures that
aim at regeneration of lost periodontal structures (ie.
cementum, periodontal ligament (PDL), alveolar bone)
• Exclusion of the faster-growing epithelium and
connective tissue from a periodontal wound for a
period of 6 to 8 weeks allows the slower growing
tissues to occupy the space adjacent to the tooth.
 GTR consist of placing barriers of different types
to cover the bone & periodontal ligament, during the
post surgical healing phase not only prevents epithelial
migration into wound but also favors repopulation of
the area by cells from the periodontal ligament &
bone.

16. REGENERATIVE PERIODONTAL
THERAPY
Periodontal regeneration:
It is defined as the reproduction or
reconstitution of lost or injured part so that the
form and function of lost structures are
restored.
Periodontal repair:
It is defined as healing that does not
completely restore the architecture or function
of the part. Periodontal repair is healing by a
long junctional epithelium.
Currently periodontal therapy aims for
regeneration and not repair

18. It has been suggested that certain steps are needed to
successfully complete the process of regeneration on
the cellular level:
• Infected tissues must be eliminated and the healing
site kept free of pathogens.
• Population of progenitor cells must be adjacent to the
wound site.
• The progenitor cells must differentiate and then
proliferate.
• The new cells (after differentiation and proliferation)
must migrate to the appropriate sites on the tooth
surface.
• Once migrated, the new cells must establish cell
population that will be responsible for long-term tissue
maintenance of the attachment apparatus.

19. Barriers offer three advantages during wound healing:
• Exclusion of the epithelium and gingival connective tissue cells
from the periodontal defect during healing. This will allow the
pleuripotential cells (undifferentiated mesenchymal cells) to
repopulate the periodontal defect.
• Barriers (membranes) maintain space between the defect and
the barrier, allowing the entry of regenerative cells from the
periodontal ligament.
• Barrier helps to stabilize the clot. This may help in
regeneration.

20. Indication for GTR
- Intra bony defects.
- Furcations in lower molars.
- Alveolar ridge augmentation.
- Gingival recession.
Contra- indications for GTR:
- Class II furcations on the mesial and distal maxillary
molars.
- Class III furcations.
- Premolar furcations.
- Horizontal bone loss.
- One wall intrabony defects.
Other factors that can influence the outcome of GTR procedure are patient’s
health, compliance, and tooth mobility.
Any medication, condition or disease, such as poorly controlled diabetes
mellitus which may interfere with patient’s healing may also be a
contraindication for this procedure.

21. Requirements of a tissue- guiding barrier:
1- Biocompatibility.
2- Stability: Barrier must create a space
adjacent to the root surface to allow in growth
of tissues from the periodontal ligament (some
materials are too soft that they collapse in the
space or too hard that they perforate overlying
tissue).
3- Clinical manageability: Membranes should be
done in a way so as to provide shapes which are
easy to trim and place.

22. Technique for GTR
Surgery is initiated by:
• Sulcular incisions.
• Vertical releasing incisions on buccal aspect of the jaw or extention
of the sulcular incision one tooth mesially or distally.
• Care should be taken to preserve the interdental papilla.
• All pocket epithelium is excised.
• All granulation tissue is removed.
• Thorough debridement of the root surfaces is performed.

23. • Various types of membranes are available in a variety of shapes
designed for specific applications. The shape most suitable for covering
the defect is selected and additional adjustment is performed
according to the defect.
• The shaping of the barrier is done in such a way that it adapts closely to
the tooth and is completely covering the defect extending at least 3
mm on the bone beyond the defect margins after placement. This
assures a good stability of the material and protects the underlying
blood clot during healing.

24. Technique for GTR
• The barrier materials are fixed to the tooth with sutures using the sling
technique. For best results, the barrier should be placed with its margin
2-3 mm apical to the flap margin. The interproximal space near the
barrier should be closed first.
• To reduce the risk of infection and ensure optimal healing, the patient
should be instructed to gently brush the area post operatively with a
soft bristle tooth brush and to rinse with chlorhexidine gluconate (0.2%)
for at least 4 weeks.
• In addition, systemic antibiotics are frequently administered before
surgery and during 1-2 weeks after surgery.
• Non-resorbable membranes are removed after 4-6 weeks.

25. Technique for GTR

26. Membranes are classified into
Non-Resorbable
membranes
Ex.Core-tex
(Polytetrafluoroethylene)
(e-PTFE).
Resorbable
membranes
Polymer membrane
Ex.
Atrisorb
vicryl
Guidor membrane.
Resolut
Epi-Guide
Collagen membranes
Ex.
Bovine tendon collagen (Biomend)
Porcine collagen (Bioguide)

27. Non-absorbable barriermembranes
• The most commonly used one is expanded polytetrafluorethylene
(ePTFE) which may be re-enforced with titanium. It is inert, does not
result in tissue reactions when implanted in the body.
• This type of membrane persists after healing and must be removed
by a second operation.
• Advantage of non-resorbable barriers is its persistence for a suitable
period of time to support the process of GTR.
• Suture material of choice is e-PTFE suture. Since the suture must
remain subgingivally in some sites, it should be biocompatible. The
flap may be sutured with the remaining e-PTFE suture.

28. • Vertical mattress sutures are commonly used to minimize
amount of suture beneath the flap and to help draw flaps
coronally. It is preferable to cover the membrane completely.
• Periodontal dressing: It may or may not be used. However,
studies have shown that the dressing may lead to bacterial
accumulation.

29. A, After flap elevation and debridement, mandibular first molar shows distal root
with extensive bone loss facially and distally, as well as grade II furcation
involvement. B, Bone replacement graft (DFDBA) in position, C, Barrier membrane
(ePTFE) over bone graft. D, Appearance of new tissue at time of membrane
removal (6 weeks after surgery) suggestive of new alveolar bone. E, Reentry after 2
years shows bone

30. Postoperative treatment:
• Post operative care is critical for success of GTR procedures. It is
important to see patient weekly as long as the barrier is in place.
• Any debris beneath coronal portion of flap must be removed and oral
hygiene re-enforced.
• Chlorhexidine is prescribed.
• Post operative antibiotics is important to suppress subgingival plaque.
Barrier removal:
• Non-absorbable barriers are removed after 6-8 weeks. Due to the
porous structure, of the membrane, soft tissue may adhere and
penetrate into it. It may sometimes be necessary to reflect a small flap
and dissect the barrier from the adjacent tissues.
Complications:
• Complications that are unique to GTR included barrier exposure and
infection around the barrier.
• This may be due to flap necrosis. Flap necrosis may occur due to
excessive thinning of the flap or protrusion of a sharp corner of the
barrier.

31. Membranes are classified into
Non-Resorbable
membranes
Ex.Core-tex
(Polytetrafluoroethylene)
(e-PTFE).
Resorbable
membranes
Polymer membrane
Ex.
Atrisorb
vicryl
Guidor membrane.
Resolut
Epi-Guide
Collagen membranes
Ex.
Bovine tendon collagen (Biomend)
Porcine collagen (Bioguide)

32. Bioabsorbable materials
• Bioabsorbable barriers have been introduced in order to avoid
a second surgery for membrane removal.
1- Collagen:
Collagen in GTR barriers is of various
sub-types (usually type I collagen is
predominant).
It is derived from various animal
sources (bovine tendon). Collagen
barriers have been shown to inhibit
apical migration of epithelial cells and
enhance new connective tissue
attachment in periodontal wounds.
The main drawback in collagen
barriers is the probability of eliciting
an immune response.
2- Polylactic acid and
polyglycolic acid polymers:
These polymer barriers are
synthesized by copolymeriztion
of different forms of polylactic
acid (PLA), polyglycolic acid (PGA)
or mixtures of both.
Barrier degradation occurs by
hydrolysis of ester bonds. This
process requires nearly 30-60
days.
Five major commercial polymers
available are guidor, vicryl,
atrisorb, resolut and Epi-Guide.

33. Bioabsorbable materials
3- Guidor
Is a hydrophobic barrier material
made of polylactic acid (PLA)
combined with citric acid ester
(softening agent). The barrier is
bilayered. An external layer (facing
gingival tissues) which has large
rectangular perforations, and an
internal layer (facing the tooth/root)
that has smaller circular perforations.
Barrier is made with absorbable
sutures attached and continuous with
the collar region. The material is
designed to resist and degradation for
up to 3 months, then gradually resorbs
and is replaced by newly regenerated
periodontal attachment
4- Vicryl:
It is a periodontal mesh made
from copolymer of glycolide and
lactide. It is available in a woven
or knitted mesh. It is thought to
degrade over a period of 3-12
weeks.

34. Bioabsorbable materials
5- Atrisorb:
Consists of a polymer of lactic acid,
poly (D, L lactide), dissolved in N-
methyl-2-pyrolidone (NMP).
Atrisorb is prepared as a solution that
coagulates or sets to a firm
consistency on contact with water or
other aqueous solutions.
6- Resolut:
It is a copolymer of PGA and PLA
that degrades over a period of 4
weeks to 8 months. Its results are
similar to e-PTFE due to its
prolonged resorption time.
7- Epi-Guide:
It is a hydrophilic membrane formed from
PLA. It contains a flexible open cell
structure (thought to enconrage uptake of
fluid blood and adherence to tooth
surface) and internal void spaces (thought
to support the blood clot formation).

36. III- Preparation of the root
surface (root conditioning)
• When teeth lose the attachment, the previously anchored
fibres of gingival connective tissue and the periodontal
ligament become infiltrated with inflammatory cells and lose
their collagen. This is caused by bacteria and their products
and results in a hypermineralized layer with bacterial that
affect on regeneration by inhibiting attachment of new cells.
• To enhance the probability for regeneration, it has been
suggested that the root surface be free from bacteria and
their by- products. Numerous mechanical methods are
available to accomplish this removal of highly calcified
material loaded with bacteria and its by- products being
spread over the root. This residue is called the “smear layer”
and is formed regardless of the manner by which the tooth is
cleaned.

37. Preparation of the root surface (root
conditioning)
1- Citric acid
2- Tetracycline
3- EDTA

38. Citric acid
Citric acid: is used as an adjunct (helper) in periodontal
therapy. It may act by:
Removal of endotoxin from root surface.
Exposes the dentin and cementum collagen matrix
providing anchorage for new fibrin clot and new collagen
fibrils.
Tetracycline: used for root conditioning may act by:
Exposing the dentin and cementum collagen (by demineralization).
Removes endotoxin.
Has anticollagenolytic effect which may retard collagen break down.
May promote fibroblast adhesion and growth.
Has an antimicrobial effect.
Tetracycline conditioning may be done by applying 125 mg tetracycline
per 1 ml saline to the root surface for 3 minutes.

39. EDTA (Ethlene diamine tetra acetic
acid):
It has been recently suggested for use
in periodontal regeneration. It acts by
demineralizing the root surface and
exposes the collagenous dentine
matrix, without affecting vitality of the
surrounding periodontal tissues
because it is neutrally buffered.

41. IV- Biologic mediators for periodontal regeneration:
Successful periodontal regeneration should lead to
regeneration of multiple tissues such as cementum,
periodontal ligament, bone and gingiva.
The regeneration of any tissue type is a complex
biological process which requires complicated
interactions between cells, locally acting growth
factors, systemic hormones and growth factors,
extracellular matrix components and attachment
factors.
The key to tissue regeneration is to stimulate a series
of events which can result in coordination and
completion of the tissue formation.

42. Among the various biologic approaches used to
promote regeneration are:
1- Growth and differentiation factors:
• Platelet derived growth factor (PDGF).
• Insulin derived growth factor (IDGF).
• Fibroblast growth factor (FGF).
2- Mediators of bone metabolism
• Bone morphogenetic proteins (BMP’s).
3- Attachment factors (Fibronectin).
4- Extra cellular matrix proteins (Enamel matrix
proteins).

43. 1- Growth factors
• “Growth factors” is a term used to describe a class of proteins
that stimulate a wide variety of cellular events such as
proliferation, chemotaxis, differentiation and production of
extracellular matrix proteins.
• Proliferation and migration of periodontal ligament cells and
synthesis of extracellular matrix as well as differentiation of
cementoblasts and osteoblasts is a prerequisite for obtaining
periodontal regeneration.
• Therefore, it is possible that growth factors may represent a
potential aid in attempts to regenerate the periodontium.
Among the growth factors used as adjuncts in periodontal
therapy are:
• Platelet derived growth factor (PDGF).
• Insulin like growth factor (IGF).
• Fibroblast growth factor.

44. Platelet derived growth factor (PDGF):
• It was originally identified in platelets but it was later found that
many other cell types synthesize platelet derived growth factor.
In response to the PDGF, many different cell types especially
those of mesenchymal origin respond well. The primary effect of
PDGF is that of a mitogen (i.e. it initiates cell division). For
example, osteoblasts, and periodontal cells proliferate in
response to platelet derived growth factor.
Insulin growth factor:
• Insulin Growth factor I and insulin growth factor II are peptide
growth factors with biochemical and functional similarities to
insulin. They stimulate proliferation of fibroblasts, bone cells and
also the formation of type I collagen synthesis.
• Therefore, the insulin growth factors increase both the number
of cells synthesizing bone as well as the amount of extracellular
matrix deposited by each cell.

45. 2- Mediators of bone formation
Bone morphogenetic proteins (BMP’s)
• BMP’s constitute a large family of regulatory factors.
They have been found in bone-inductive extracts of
bone.
• These BMP’s function by making mesenchymal precursor
cells differentiate into mature osteoblasts.
• BMPs also are chemotactic for some cell types of the
osteoblastic line.
• BMPs are able to induce bone formation and so are good
candidates for regeneration of alveolar bone.
• Bone morphogenetic proteins (BMP’s) are osteoinductive
factors that may have the potential to stimulate
mesenchymal cells to differentiate into bone forming
cells.

46. 3- Attachment factors - Fibronectin:
• Fibronectin is a large glycoprotein present in serum and
produced by many cells. Fibronectin is the glycoprotein that
fibroblasts require to attach to root surface i.e. it aids
attachment of cells to extracellular matrix and so has an
important role in tissue regeneration and wound healing.
• The addition of fibronectin to the root surface may promote
new attachment. It aids in clot attachment and so may delay
apical migration of epithelial cells and stimulate periodontal
ligament cells especially fibroblasts to repopulate the root
surface.
• In periodontal therapy, application of fibronectin has been
combined with surface demineralization of the root. The
rationale is that demineralization will expose collagen fibers
within the root surface and fibronectin will facilitate interaction
of gingival fibroblasts and the tooth and so connective tissues
attachment is improved.

47. 4- Extracellular matrix proteins (enamel matrix
proteins)
The enamel matrix derivative (EMD) for
periodontal regeneration has been suggested
because it resembles the way these materials
behave in normal tooth development. These
enamel matrix proteins appear to be involved in
formation of cementum. They have been found to
stimulate regeneration of firmly attached acellular
cementum.
Combination of any of the previous regenerative
techniques may be performed.