Bone graft in Periodontology Copyright (c) by Department of Periodontology University of Dental Medicine, Yangon

1. BONE GRAFT
DEPARTMENT OF
PERIODONTOLOGY, UDMY

2. BONE GRAFT
• The primary goal of periodontal treatment is the maintenance of the
natural dentition in health and comfortable function. When
periodontal disease has caused a loss of the attachment apparatus,
optimal care seeks to regenerate the periodontium to its pre-
disease state.
• Regeneration has been defined as the reproduction or
reconstitution of a lost or injured part to restore the architecture and
function of the periodontium.

3. • Bone grafts and their synthetic substitutes have been used in an
attempt to gain this therapeutic endpoint.
• Unlike other tissues, bone has the unique capcaity to regenerate
itself completely.
• The major limiting factor is maintenance of space for bone
formation.
• Bone graft materials have been used to facilitate bone formation by
occupying the space and allowing the subsequent bone growth.

4. • The biologic mechanisms that support the use of bone graft
materials are:
• Osteoconduction
• Osteoinduction
• Osteogenesis

5. Osteoconduction
• It is the formation of bone by osteoblasts from the margins of the
defect on the bone graft material.
• It serves as scaffold for bone growth.
• It does not inhibit nor induce bone formation.
• It facilitates bone formation by bridging the gap.
• It simply allows the normal formation of bone by osteoblasts into
the grafted defect along the surface of the graft material.

6. Osteoinduction
• It involves new bone formation via stimulation of osteoprogenitors
from the defect (from vasculature) to differentiate into osteoblasts
and begin forming new bone.
• This induction of the bone-forming process by cells that would
otherwise remain inactive occurs via cell mediators that turn on
these bone forming cells.
• Bone morphogenic proteins (BMPs)

7. Osteogenesis
• It occurs when living osteoblasts are part of the bone graft as in
autogenous bone transplantation.
• Given an adequate blood supply and cellular viability, these
transplanted osteoblasts from new centers of ossification within the
graft.
• Osteoblasts that already exist and added as part of the bone graft
form ossification centers and contribute to the total capacity for
bone formation.

8. • Numerous bone graft materials have been used to aid in the
reconstruction of bone defects.
• At a minimum, bone graft materials should be osteoconductive.
• Osteoconductive are more advantageous than osteoconductive.

9. Bone graft materials
1. Autograft
A. Intraoral
B. Extraoral
2. Allograft (derived from same species)
3. Xeno graft (derived from different species)
4. Alloplast or synthetic graft

10. 1. Autograft
A. Intraoral sites (harvested form) -
• Healing extraction site
• Edentulous ridge
• exostosis
• maxillary tuberosity
• chin
• trephined from the jaw without daaging the roots
• removed during osteoplasty and ostectomy

11. 2. ALLOGRAFT (ALLOGENIC BONE GRAFTS)
Four types of allografts:
• Frozen cancellous iliac bone and marrow
• Cryopreserved bone from the head of a femur
• Freeze-dried bone allograft (FDBA)
• Demineralized freeze-dried bone allograft (DFDBA or FDDBA)

12. • The only materials with human histological evidence to substantiate
their regenerative use are autogenous bone graft and DFDBA.
• It is important to understand screening protocol of tissue bank that
is procuring and processing the graft in donor selection, processing
technique and particle size.

13. DFDBA
• Urist and coworkers have established the osteogenic potential of
DFDBA.
• Demineralization in cold, diluted hydrochloric acid exposes the
compnents of bone matrix, closely associated with collagen fibrils,
that have been termed bone morphogenetic protein.

14. 3. XENOGRAFTS
• Calf bone, Kiel bone and anorganic bone: These materials have
been discarded for various reasons.
• Recently, Yukna and coworkers have used a natural, anorganic,
microporous, bovine-derived hydroxyapatite bone matrix, in
combination with a cell-binding polypeptide.

15. 4. ALLOPLAST (SYNTHETIC BONE GRAFTS)
• A number of synthetic or inorganic graft materials are available for
use in the treatment.
• They act almost exclusively as biological fillers, with scant bone fill
and very limited connective tissue regeneration.
• The can be classified by their ability to be bio-absorbed.
• The absorbable materials
• The non-absorbable materials

16. The absorbable materials are:
• ceramics
• beta tri-calcium phosphate
• hydroxyapatite
• calcium sulfate and calcium carbonate

17. The non-absorbable materials are:
• porous hydroxyapatite
• dense hydroxyapatite
• bioactive glass
• calcium-coated polymer of hydroxyethylenethacrylate and
polymethylmethacrylate

18. • Bone graft materials help maintain space to facilitate the formation
of bone within a confined space.
• They should facilitate the ingrowth of neovascularization and
migration of osteoprogenitors.
• The size of bone graft particles determine the resultant space
available for osseous formation.
• The typical size of bone graft particles ranges from 100-1000 µm,
which is conductive to the ingrowth of bone.

19. Requirements for bone regenerations :
• blood supply
• stabilization
• osteoblasts
• confined space
• space maintenance
• wound coverage

20. • All grafting techniques require pre-surgical 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.

21. GUIDED TISSUE REGENERATION
• The method for the prevention of epithelial migration along the cemental wall of
the pocket that has gained wide attention is the guided tissue regeneration
(GTR).
• This method derives from the classic studies of Nyman, Lindhe Karring and
Gottlow. It is based on the assumption that only the periodontal ligament cells
have the potential for regeneration of the attachment apparatus of the tooth.
• Placing barriers of different types to cover the bone and periodontal ligament,
thus temporarily separating them form the gingival epithelium.
• Excluding the epithelium and the gingival connective tissue from the root
surface during the post surgical healing phase not only prevents epithelial
migration into the wound but also favors repopulation of the area by cells from
the periodontal ligament and the bone.

22. Type to enter a caption.

23. BARRIER MEMBRANES
There are five criteria considered to be important in the design of
barrier membranes used for GTR.
1. Biocompatibility
2. Cell-occlusiveness
3. Space making
4. tissue integration
5. Clinical manageability

24. • There are two types of barrier membrane :
1. Non-resorbable
2. Resorbable

25. 1. NON-RESORBABLE MEMBRANE
• The first membrane used experimentally by Nyman’s group in their initial
work were constructed from millipore (cellulose acetate) fitters since these
were easily available in the laboratory and were packed and stored in
sterile conditions.
• The first of these were made from Teflon® (expanded
polytetratfluoroethylene, ePTFE). This material was biocompatible in the
human body. (It has been used for sometime in reconstructive vascular
surgery for replacement atreries.)
• Collar portion: having open pores to allow ingrowth of connective tissue and
to prevent epithelial migration
• Occlusive portion: Preventing the flap tissue from coming into contat with
the root surface

26. • Because the space defined and protected by the membrane
determined the volume of tissue that could be regenerated the
material was redesigned with a titanium for both osseous and
periodontal defects.
• Since these membranes are made of a non-resorbable material, a
second surgical procedure is necessary to remove them.
• This procedure therefore has the disadvantage of additional trauma
to the patient as to the healing periodontal tissues.

27. 2. RESORBABLE (OR) BIOABSORBABLE MEMBRANES
There are basically two types of biologically resorbable membranes:
1. Synthetic
• Polyurethane
• Polylactic acid
• lactide glycolide co-polymens, e.g., Polygalctin 910
• Polylactic acid blended with citric acid ester
2. Natural biomaterials
• Collagen