Reconstructive periodontal surgery (part1+2+3)

Reconstructive Periodontal Surgery
Dr. Oinam Monica Devi
PART - I ( TECHNIQUES)

Contents
• Introduction
• Periodontal wound healing
• History
• Assessment of Periodontal Wound Healing
• The evolution of flap designs for periodontal regeneration
• Techniques
• Non–Graft-Associated Reconstructive Procedures
• Bone- Graft Associated Reconstructive Procedures
• Cell therapy
• Gene therapy
• 3-D scaffold and techniques

Introduction
• Regenerative periodontal therapy comprises procedures which are specially
designed to restore those parts of the tooth‐supporting apparatus which
have been lost due to periodontitis.
• Regeneration is defined as a reproduction or reconstruction of a lost or
injured part in such a way that the architecture and function of the lost or
injured tissues are completely restored (American Academy of
Periodontology 1992).

• Reconstructive or regenerative techniques are used either singly or in
combination for three main purposes:
(1) To regain lost periodontal ligament attachment
(2) To provide a wider zone of attached gingiva
(3) To cover previously exposed root surfaces

• The most common periodontal indications periodontal regeneration
procedures include:
 Deep infrabony defects,
 Furcation defects of upper premolar and molar teeth
 Localized gingival recession defects
• Periodontal regenerative therapy
1. New barrier membrane techniques
2. Cell‐growth stimulating proteins
3. Cell and gene delivery applications
4. Optimized scaffold
5. Fabrication technology

Advantages and Disadvantages of Regenerative
Procedures
Advantages
1. Lost periodontal tissues restored
2. Less gingival recession
postoperatively
• Esthetic
• Less possibility of hypersensitivity
• Low risk of root surface caries
Disadvantages
1. Longer treatment time.
2. Technically demanding.
3. Pre- and postoperative plaque
control and maintenance mandatory
4. Second surgery may be required to
eliminate remaining periodontal
pocket and osseous defect
5. Costly

• The clinical outcome of periodontal regenerative techniques has been shown to
depend on (McCulloch 1993)
(1) Patient‐associated factors such as plaque control, smoking habits, residual
periodontal infection, or membrane exposure in guided tissue regeneration
(GTR) procedures.
(2) Effects of occlusal forces that deliver intermittent loads in axial and transverse
dimensions.
(3) Factors associated with the clinical skills of the operator, such as the failure of
primary closure of the surgical wound.

Periodontal wound healing
• When the periodontium is damaged by inflammation or as a result of surgical
treatment, the defect heals either through periodontal regeneration or repair.
• Histologically, patterns of repair include long junctional epithelium, ankylosis,
and/or new attachment.
• The ideal goal of periodontal surgical therapy is periodontal regeneration.
• In periodontal regeneration, healing occurs through the reconstitution of a new
periodontium, which involves the formation of alveolar bone, functionally
aligned periodontal ligament, and new cementum.

Possible healing patterns for a periodontal wound.
Carranza ,
13th ed

History
• Research by Tony and his colleagues
(1980;1983)showed that in steady-state and
wounding conditions, the regions around blood
vessels in the periodontal ligament were enriched
with progenitor cells.
• They found that these progenitors could give rise
to fibroblasts, cementoblasts and osteoblasts.
• They also discovered that the periodontal
ligament was not a closed cell system; instead,
cells from adjacent endosteal spaces migrated
through vascular channels into the periodontal
ligament and there contributed to the progenitor
cell populations that could synthesize bone,
cementum and the periodontal ligament itself.
Brunette et al.

Assessment of Periodontal Wound Healing
• The proof of principle for the type of healing is determined by histologic
studies.
• Once defined, the evidence found subsequently by clinical, radiographic,
and surgical reentry findings is implied.

Histologic Methods
• Only through histologic analysis can one define the nature of the reparative
tissue.
• In periodontal reconstructive surgery, the goal is to achieve periodontal
regeneration.
• Classically, experimental animal model systems are used whereby
reference notches are placed at the base of bony defects or at the apical
extent of calculus deposits.

• Periodontal regeneration is considered to have
occurred when the newly formed functionally
aligned periodontium is coronal to the apical
extent of the notches.
• The healing may be dominated by periodontal
regeneration; localized areas of repair may be
present.
Carranza , 13th ed

Clinical Methods
• Clinical methods to evaluate periodontal reconstruction consist of comparisons
between pretreatment and posttreatment pocket probings and determinations of
clinical gingival findings.
• Clinical determinations of attachment level are more useful than probing pocket
depths because the latter may change as a result of displacement of the gingival
margin.
• Measurements of the defect should be made before and after treatment from
the same point within the defect and with the same angulation of the probe.
• This reproducibility of probe placement is difficult and may be facilitated in part
by using a grooved stent to guide the introduction of the probe.

• The use of various surgical techniques in conjunction with the implantation
of bone grafts/bone substitutes for Periodontal regeneration
• Root-surface demineralisation;
• Guided tissue regeneration (GTR)
• Growth and differentiation factors
• Enamel matrix derivative (EMD)
• Various combinations of the above

Guidelines to select the patients for regenerative therapy
• Patients should be treated with regeneration after completion of cause-related
therapy consisting of scaling and root planing, motivation and oral hygiene
instructions.
• Full mouth plaque and full mouth bleeding scores should be equal to, or smaller
than, 15%.
• A very high standard of home care and compliance have to be required from the
candidate patient in order to achieve and maintain optimal clinical outcomes.
• Preferably, only non-smoking patients should be treated, since cigarette smoking
negatively affects the outcomes.

Sculean A ,2017
Decision tree for regenerative therapy in intrabony defects

Barbagallo G, 2020
The complete decision tree

Decision tree for regenerative therapy in furcation defects
Sculean A ,2017

• It starts with tissue-preservation surgical approaches:
1. Retained interdental papilla
2. Papilla Preservation Technique
3. Modified PPT
4. Interproximal Tissue Maintenance Approach
5. Simplified Papilla Preservation Flap
6. Crestal Incision

The evolution of flap designs for periodontal regeneration
Ausenda F, 2019

To move to MIS approaches, which can be divided into:
1. Techniques that require the use of biomaterials and membranes
• Minimally Invasive Surgery
• Single Flap Approach
• Coronally Advanced-SFA
2. Techniques that exploit the flap design
• Minimally Invasive Surgical Technique
• Modified-MIST
• Entire Papilla Preservation Technique

• (Cardaropoli , 2003) : The epithelium only starts migrating over the alveolus
once the granulation tissue starts replacing the blood clot, and it never goes
beyond the level reached by the granulation tissue.
• The same is probably true even for the periodontal defects—when a blood clot is
stable and the tooth mobility is low, the epithelium may have to wait for
granulation tissue to form before starting to migrate into the defect.
• With this concept in mind, surgical techniques have evolved from large flaps to
smaller ones in the attempt to preserve the soft tissues as much as possible.

• In the 2020 EFP clinical guidelines for the treatment of periodontitis, a
systematic review and metaanalysis concluded that papilla-preserving flaps
improve clinical results and should be considered as surgical prerequisites
when conducting regenerative/reconstructive therapies.
• Better clinical results were seen with minimally invasive surgical
techniques that aimed at preserving the soft tissue and limiting the mobility
of the flap as much as possible.

Papilla preservation Flap
Devised by Takei and colleagues (1985, 1988, 1991)
Advantages
1. Esthetically pleasing
2. Primary coverage of
implant material
3. Prevention of
postoperative tissue
craters
Disadvantages
1. Technically difficult
2. Time consuming
Contraindication
1. Narrow embrasures

1. Buccally, interproximally, &
palatally/lingually, the flaps are relieved with
intrasulcular incisions.
2. Vertical incisions are made palatally/lingually
adjacent to the papillae that are to be moved. The
vertical incisions are extended far enough
apically so that they will be at least 3 mm apical
to the margin of the interproximal bony defect
and 5 mm from the gingival margin (Fig A and
B).
3. The vertical incisions are joined by a
horizontal incision, which can be made with a
Kirkland knife (Fig 8-5B).
4. For flap reflection, a curet or interproximal
knife is used to free the interdental tissue
from the underlying tissue. Note: The papilla
must be completely mobile prior to reflection
(FigC).
5. With a blunt instrument, the papilla is carefully
pushed through the embrasure,
excessive granulation is removed from the
underside with a sharp scissors or curet.
Overthinning is to be avoided (FigD).
6. Both the flap and the papilla are reflected
off the bone with a periosteal elevator (Fig-5E).
7. Once the defect area is débrided and filled,
the flaps are repositioned and the papilla is
pushed back through the embrasure and
sutured with interrupted or horizontal mattress
sutures (Fig I).
Procedure

The modified papilla preservation technique (MPPT)
• The rationale for developing this technique was to achieve and maintain
primary closure of the flap in the interdental space over the membrane
(Cortelliniet al. 1995)
• It includes a buccal incision of the defect-associated interdental papilla that is
elevated with the full thickness palatal flap.
• It can be successfully applied in interdental sites wider than 2mm, as when the
interdental site is narrower the technique is difficult to apply.
• Cortellini P,1995 in a randomised controlled clinical study on 45 patients,
significantly greater amounts of attachment gain were obtained with the
MPPT (5.3±2.2mm), in comparison with either conventional GTR
(4.1±1.9mm) or flap surgery (2.5±0.8mm). Primary closure of the defect-
associated papilla was observed in 97% of the treated sites and maintained in
73% of them upto six weeks later when the membrane was removed.

1. After elevation of a full thickness buccal flap, the residual interdental tissues are dissected
from the neighboring teeth and the underlying bone, and elevated towards the palatal aspect.
2. A full‐thickness palatal flap, including the interdental papilla, is elevated and the interdental
defect exposed.
3. Following debridement of the defect, the buccal flap is mobilized with vertical and
periosteal incisions, when needed.
4. To obtain primary closure of the interdental space over the membrane, a first suture
(horizontal internal crossed mattress suture) is placed beneath the mucoperiosteal flaps
between the base of the palatal papilla and the buccal flap.
5. The interdental portion of this suture hangs on top of the membrane, allowing the coronal
displacement of the buccal flap. This suture relieves all the tension in the flaps.
6. To ensure primary passive closure of the interdental tissues over the membrane, a second
suture (vertical internal mattress suture) is placed between the buccal aspect of the
interdental papilla (i.e. the most coronal portion of the palatal flap, which includes the
interdental papilla) and the most coronal portion of the buccal flap. This suture is free of
tension.
Technique

Clinical case illustrating the modified papilla preservation technique (MPPT) used to
completely close the interdental space above a barrier membrane.
Lindhe ,
6th ed

The simplified papilla preservation flap (SPPF)
• It has been proposed to apply in interdental spaces of 2mm or narrower.
• Developed by Cortellini et al. 1999
• This approach includes an oblique incision across the defect-associated
papilla, starting from the buccal line angle of the defect-associated tooth to
reach the mid-interdental part of the papilla at the adjacent tooth, under the
contact point.

1. First incision across the defect‐associated papilla, starting from the gingival margin at the
buccal‐ line angle of the involved tooth and extending to the mid‐interdental portion of
the papilla under the contact point of the adjacent tooth.
2. This oblique incision is carried out by keeping the blade parallel to the long axis of the
teeth in order to avoid excessive thinning of the remaining interdental tissues.
3. The first oblique interdental incision is continued intrasulcularly in the buccal aspect of
the teeth neighboring the defect.
4. After elevation of a full‐thickness buccal flap, the remaining tissues of the papilla are
carefully dissected from the neighboring teeth and the underlying bone crest.
5. The interdental papillary tissues at the defect site are gently elevated along with the
lingual/palatal flap to fully expose the interdental defect.
6. Following defect debridement and root planing, vertical releasing incisions and/or
periosteal incisions are performed, when needed, to improve the mobility of the buccal
flap.
Technique

7. After application of a barrier membrane, primary closure of the interdental tissues above
the membrane is attempted in the absence of tension, with the following sutures:
 A first horizontal internal mattress suture (offset mattress suture) is positioned in the
defect‐associated interdental space running from the base (near to the mucogingival
junction) of the keratinized tissue at the mid‐buccal aspect of the tooth not involved with
the defect to a symmetrical location at the base of the lingual/palatal flap.
One interrupted suture whenever the interdental space is narrow and the interdental tissues
thin; two interrupted sutures when the interdental space is wider and the interdental
tissues thicker; an internal vertical/oblique mattress suture when the interdental space is
wide and the interdental tissues are thick.

Simplified papilla preservation flap
Lindhe , 6th ed

Minimally invasive surgical technique
• Harrel and Rees (1995) proposed the minimally invasive surgery (MIS)
approach with the aim of producing minimal wounds, minimal flap reflection,
and gentle handling of the soft and hard tissues.
• In order to provide even greater wound stability and to further limit patient
morbidity, a papilla preservation flap can be used in the context of a minimally
invasive, high‐power magnification‐ assisted surgical technique (Cortellini &
Tonetti 2007a).
• Such a minimally invasive approach is particularly suited for treatment in
conjunction with biologically active agents such as EMDs or growth factors
and/or grafting materials.

1.The defect‐associated interdental papilla is accessed either with the SPPF (Cortellini et al.
1999) or the MPPT (Cortellini et al. 1995).
2. The SPPF is performed whenever the width of the interdental space is 2 mm or narrower, while
the MPPT is applied at interdental sites wider than 2 mm.
3. The interdental incision (SPPF or MPPT) is extended to the buccal and lingual aspects of the
two teeth adjacent to the defect.
4.These incisions are strictly intrasulcular to preserve all the height and width of the gingiva, and
their mesiodistal extension is kept to a minimum to allow the coronoapical elevation of a very
small full‐thickness flap with the objective of exposing just 1–2 mm of the defect‐associated
residual bone crest.
5.When possible, only the defect‐associated papilla is accessed and vertical releasing incisions
are avoided.
6. With these general rules in mind, different clinical pictures can be encountered in different
defects.

Modified-Minimally invasive surgical
technique (M‐MIST)
• The MIS (Harrel 1995) and the MIST (Cortellini & Tonetti 2007) include the elevation of
the interdental papillary tissues to uncover the interdental space, gaining complete access to
the intrabony defect, while in the M‐MIST (Cortellini & Tonetti 2009a) access to the defect
is gained through the reflection of a small buccal flap, without elevation of the interdental
papilla.
• The minimal flap reflection narrows the angle of vision and especially the light penetration
into the surgical field.
• The soft tissue manipulation during instrumentation requires more care since the flaps.
• Use of small instruments, like small periosteal elevators and tiny tissue players, is
mandatory for soft and hard tissue manipulation.
• Microblades, mini‐curettes, and mini‐scissors allow for full control over the incision,
debridement, and refinement of the surgical area, and sutures from 6‐0 to 8‐0 are mandatory
for wound closure.

Single Flap Approach
• This approach involves elevation of only 1 flap ( buccal) and leaving the
other intact.
• It can be considered for treating defects in areas with higher esthetic
demands.
• When this approach is used with graft , there is reported decrease in
probing depth and CAL gain.
Trombelli, 2008

Soft Tissue
Wall
Technique
Rasperini G et al. 2013

Connective Tissue Wall Technique
• The regenerative surgery consisted of palatal incisions to access the bony
defects and use of a combination of EMD and a CTG under a coronally
advanced buccal flap.
Zucchelli et al. 2017

1.After local anesthesia, horizontal split-thickness
incisons were made at the base of the palatal anatomical
papillae covering the intrabony defects and at the base of
the two palatal papillae of the interdental spaces
neighboring the defects.
2. The palatal incisions were beveledas much as possible
in relation to the palatal soft tissue thickness to elevate a
split-thickness flap.
3.Once the palatal bone was reached, flap elevation
continued full thickness.
4.Similar split thickness incisions were made at the base of
the palatal papillae of the interdental spaces neighboring
the defect.
5.The supracrestal soft tissue was separated from the
palatal bone with a horizontal split-thickness incision
&then pushed from the palatal to the buccal aspect below
the contact point.
6. The buccal flap was raised with submarginal split-
thickness surgical papillae at the interdental spaces
neighboring the defect area, while full-thickness elevation
was performed to complete buccal elevation of the
supracrestal soft tissue coming from the palatal aspect.
Buccal view
Palatal view

Entire Papilla Preservation Flap
Aslan et al, 2017
1.The entire procedure is like a
tunnel- like approach of the
defect associated interdental
papilla.
2. Surgical loupe for visibility.
3. A buccal intracrevicular
incison followed by bevelled
vertical releasing incison is made
on the buccal gingiva of
neighbouring interdental space
and extended just just beyond
the mucogingival line to provide
appropriate mechanical access to
the intrabony defect.

Non–Graft-Associated Reconstructive Procedures
Historical interest
Removal of Junctional and Pocket Epithelium
Curettage
Chemical
agents
Ultrasonics Lasers
Surgical
techniques
•Curretage: not a reliable procedure, occasional bone regeneration does occur.
•The effects of ultrasonic methods, lasers, cannot be controlled because of the clinician's lack of vision
and tactile sense when using these methods.
•Chemical agents (sodium sulfide, phenol camphor, antiformin, sodium hypochlorite) used to remove
pocket epithelium in conjunction with curettage with an uncontrolled depth of penetration.

Biomodification of the tooth-root surface
• All periodontal surgical procedures give access to the root surface to allow
thorough debridement.
• Demineralisation of debrided/planed root surfaces removes the smear layer,
exposing collagen fibrils, and may enhance initial adhesion of the blood
clot/connective tissue of the flap and subsequently allow formation of a collagen
fibre linkage.
• Biomodification of the root surface with enamel matrix proteins during
periodontal surgery and following demineralization with EDTA has been
introduced to promote periodontal regeneration.

Citric Acid
• The following actions of citric acid have been reported:
1. Accelerated healing and new cementum formation occur after surgical detachment
of the gingival tissues & demineralization of the root surface.
2. Topically applied citric acid on periodontally diseased root surfaces has no effect on
nonplaned roots, but after root planing, the acid produces a 4-μm-deep demineralized
zone with exposed collagen fibers.
3. Root-planed, non–citric acid–treated roots are left with a surface smear layer of
microcrystalline debris.
4. Citric acid has also been shown in vitro to eliminate endotoxins and bacteria from
the diseased tooth surface.
5. An early fibrin linkage to collagen fibers exposed by the citric acid treatment prevents
the epithelium from migrating over treated roots.

• The recommended citric acid technique is as follows:
1. Raise a mucoperiosteal flap and thoroughly instrument the root surface, thus
removing calculus and underlying cementum.
2. Apply cotton pledgets soaked in a saturated solution of citric acid (pH of 1.0)
for 2 to 5 minutes.
3. Remove pledgets, and irrigate root surface profusely with water.
4. Replace the flap and suture.
• Fibronectin and tetracycline are other agents used for root biomodification.

Previous Surgical techniques
The excisional new attachment procedure (ENAP)
• Consists of an internal bevel incision performed with a surgical knife,
followed by removal of the excised tissue.
• No attempt is made to elevate a flap.
• After careful scaling and root planing, interproximal sutures are used to
close the wound.
• This approach has been modified and is used in conjunction with the
ND:YAG laser in the previously described LANAP procedure.

Yukna R A, 2007
All LANAP-treated specimens showed new cementum and new connective tissue
attachment in and occasionally coronal to the notch, whereas five of the six control teeth
had a long junctional epithelium with no evidence of new attachment or regeneration.

• General principle of oral and periodontal surgery is to place the incision as much
as possible on healthy tissue to reduce:
1) Easier infection of the wound by contamination through the suture
2) Contamination of any biomaterial
3) Easy release of biomodulators
4) Poor protection of the clot
5) Increase in the REC
• Progress in GTR has one common feature: understanding and implementing the
fundamentals of clot protection and stability in the periodontal wound, based on
a reasoned MIS approach.

Guided Tissue Regeneration (currently practiced)
• The concept of guided tissue regeneration (GTR) is one that attempts to exclude
or prevent apical proliferation of epithelium in favor of other cells that will
increase the likelihood of regeneration—bone and PDL (McHugh, 1988).
• The biological rationale of the procedure is based on prevention of migration of
the epithelial periodontal tissues into the osseous defect, allowing time for bone
and other attachment tissues to heal.
• GTR techniques utilize barrier membranes to facilitate the migration of bone
cells and PDL cells to the defects by refraining soft tissue cells from penetrating
it.

• Melcher (1976) postulated that four different
connective tissues compete for the root surface
during healing:
(1) The lamina propria of the gingiva with the gingival
epithelium
(2) The PDL
(3) The cementum
(4) The alveolar bone
• Which cell phenotype succeeds in repopulating the
root surface determines the nature and quality of the
attachment and regeneration.
• The biologic basis for GTR was borne out of this
type-specific cell repopulation theory.

• The membrane provides sufficient space for optimal wound stability, an essential
prerequisite for periodontal regeneration to occur.
• Bioresorbable membranes have replaced the routine use of ePTFE membranes in GTR.
• If non-resorbable, the barrier is surgically removed 4–6 weeks after implantation.
• Connective tissue and bone regeneration may then occur within the bony lesion
protected by the barrier.
• Even with regeneration of bone, one cannot be sure that healing is not by an LJE.
• The true nature of the attachment achieved can be determined only histologically.

• GTR has a greater effect on the
probing measures of periodontal
treatment than periodontal flap
surgery alone, including
1. Increased attachment gain
2. Reduction of probing depth
3. Less gingival recession
4. More gain in hard-tissue probing
at surgical re-entry
Sato, Naoshi: A Clinical Atlas

GTR for circumferential osseous defect
Note the vertical osseous defect on the distal aspect of 18 after initial therapy. The
probing depth is 10 mm lingually and 8 mm buccally. The attachment level is 12 mm
lingually and 11 mm buccally (40-year-old woman).

GTR for root coverage

Guided Tissue Regeneration and Papilla Preservation with the “Whale’s Tail” Flap
Two vertical incisions were performed
from the mucogingival line to the distal
margin of the lateral incisor and mesial
margin of the central incisor on the
buccal surface .
A horizontal incision joined the vertical
incisions at the apical aspect of the flap.
In the coronal aspect of the flap
intrasulcular incisions were made at
buccal, interproximal and palatal sides.
The advantages of “Whale’s tail” flap are the elevation of a large flap from buccal to palatal,
allowing the preservation of a large amount of soft tissue resulting in GOOD FLAP
CLOSURE.
Introduced by Bianchi and
Basseti (2009)

A full-thickness flap was elevated from buccal to palatal side through the diastema
The defect was debrided, the root was scaled,
planned and conditioned with citric acid for
3 minutes

Autogenous bone was removed
from the palatal side with a chisel
and it was used to fill the defect
A bioresorbable bovine collagen
membrane (GenDerm®, Baumer,
São Paulo) was used to cover the
graft
The flap was repositioned from
the palatal to the buccal side, and
its margins were sutured without
tension, far away from defect

After 16 months the mesial vestibular and palatal probing depths were 3mm with a gain in
attachment of 4 and 5 mm respectively

1.GTR vs. open flap debridement: The results from both systematic reviews showed a limited
but statistically significantly greater attachment gain for test groups compared with OFD.
2. GTR vs bone substitutes : For change in probing depth, the results demonstrated a small but
significantly greater probing depth reduction for GTR + bone
2003
2001
2001

Murphy KG et al.,2003
1. GTR with ePTFE membrane vs. GTR with bioabsorbable membrane:
Meta-analysis failed to demonstrate a significant difference in clinical
attachment level gain and probing depth reduction between bioabsorbable
and non-resorbable membranes.
2. GTR + bone substitutes vs. GTR alone: Meta-analysis of the selected
studies did not reveal any adjunctive effect on either clinical attachment
level gain or probing depth reduction. There was significant heterogeneity
among the studies when clinical attachment level gain was considered (P <
0.03).

Graft Associated Reconstructive Procedures
• The original hypothesis of guided bone regeneration (GBR) was introduced
(Dahlin, Linde, Gottlow, & Nyman, 1988), implying that a non-resorbable
or biodegradable barrier could be placed to exclude certain cell types, such
as rapidly proliferating epithelium and connective tissue, thus promoting
the growth of slower-growing cells capable of forming bone.
• The concept of GTR was applied also to regenerate bone for implants.
• Buser coined the acronym GBR.
• The clinical introduction of the GBR concept, it has been realized that the
addition of membrane-supporting materials or grafts in combination with
membranes may provide synergistic effects for the regenerative outcome
(Donos, Mardas, & Chadha, 2008; Hermann & Buser, 1996)
GUIDED BONE REGENERATION
( currently practiced)

• The biological events in both the membrane and the underlying defect are
important for bone regeneration.
• The membrane has direct bone promotive effects, by virtue of hosting cells
that express and secrete pro-osteogenic and bone-promoting factors, which
are linked to the bone regeneration and restitution of the underlying defect.
• This bioactive effect has also been shown with cell and molecules
intentionally incorporated in the membrane and/or in the underlying defect,
with or without the bone grafting materials.

Sato, Naoshi: A
Clinical Atlas

PProcedure of the lateral incision technique

Using Principle Of Selective Cell Repopulation
Biologic Principle:
Mechanical exclusion of the soft tissues
from filling the osseous defect, thus
allowing the cells with osteogenic cells to
colonize the wound such that increased
volume of bone may be formed.
Key Prognostic Factor:
Enough space under the barrier membrane
to allow for bone regeneration of the
crestal defect.
RIDGE
PRESERVATIO
N
At or after
tooth
extraction
GUIDED TISSUE
REGENRATION
Improvement
in volumetric
deficiency of
ridge
First
introduced :
Hurley and
Colleagues
(1959)

GBR With Simultaneous Extraction
To regenerate bone in the
extraction socket
Prevent resorption of the
socket margin and loss of thin
facial bone plate
Preserve ridge height and width
Problems: Difficulty of complete
membrane coverage and
wound closure.
To avoid this : Cover the
exposed part of the membrane
with gingival grafts.
GBR After Healing
Of The Socket
If complete
debridement is
difficult due to an
extensive ridge
defect
Because of the
demands of primary
wound closure,
problems of the
mucogingiva and
narrow buccal oral
vestibule may occur.
GBR After Healing Of
Soft Tissue Of The
Extraction Socket
Due to severe
postoperative
mucogingival
problems, early
membrane exposure,
apical recession
GBR performed after
healing of the mucosal
epithelium of the
extraction wound (2-3
months after
extraction)

Limitations of GBR:
 Not highly predictable
 Volume of bone regeneration attainable is limited
 Ridge can be improved mainly in the horizontal dimension
 Where extensive augmentation is needed (≥3 mm), other
augmentation
techniques should be considered

• The suturing approach can be chosen according to the defect anatomy and to the
type of regenerative strategy used in each case.
• When a barrier with or without a filler is applied a combination of two sutures is
suggested to reach primary closure of the papilla in the absence of any tension.
• The first interdental suture is positioned between the apical part of the buccal
gingiva, near the mucogingival junction, and an apical area of the lingual/palatal
flap.
• The aim of this internal mattress suture is to relieve the residual tension of the
flaps in the defect-associated area and to coronally displace the buccal flap,
when needed.
• The second suture is a vertical internal mattress suture positioned at the wound
edges to passively close the interdental papilla over the regenerative material.

MANAGEMENT OF MEMBRANE EXPOSURE
With e-PTFE, if membrane exposure limited to center part
no problem
If marginal part of the membrane is not exposed
Removed 4-8 weeks after surgery with thorough plaque
control of the exposed area
If the membrane margin is exposed with Pain or discharge
Removed immediately
In the absence of these problems
Removed 4-8 weeks later followed by thorough plaque
control
If membrane exposure progresses or a large amount of
plaque builds up on the exposed membrane :
Removed 4 weeks after surgery.
 Once weekly visit (every
3 days if possible) for
professional cleaning.
 Use a bactericidal
mouthwash
 Caution is needed in the
mechanical plaque removal
to prevent damage of soft
tissue dehiscence
 A toothbrush with a soft
tuft (Ope-Go brush,
Panadex)

Post-operative protocol
• Administer systemic antibiotics for one week.
• Prescribe 0.12% chlorhexidine mouth rinsing three times per day weekly
prophylaxis for periods of 6 to 10 weeks.
• Patients are requested to avoid brushing, flossing and chewing in the treated
area.
• Sites treated with amelogenins normally require the shortest healing period,
those treated with non-resorbable barriers require the longest.
• Non-resorbable membranes are generallyremoved after 6 weeks.
• After the early healing phase, patients can resume full oral hygiene with either
manual or powered toothbrushes and interdental cleaning with dental brushes
and floss.
• Patients should be placed on monthly recall for 1 year to ensure the best
maturation of the treated site.

Cell therapy for periodontal regeneration
• For regeneration of interdental papillae, early investigations of cell therapy
using cultivated fibroblasts have shown success in the treatment of
interdental papillary insufficiency (McGuire & Scheyer 2007).
• Bone marrow stromal cells (BMSCs) are characterized by elevated renewal
potency and by the ability to differentiate into osteoblasts, chondroblasts,
adipocytes, myocytes, and fibroblasts when transplanted in vivo (Prockop
1997).

Three main approaches using cell therapies
“minimally
manipulated” whole tissue
fractions
ex vivo expanded
“uncommitted”
stem/progenitor cells
ex vivo expanded
“committed”
bone-/periosteum-
derived cells
• Preserve the physiological
microenvironment or “niche” of
multiple cell types in their natural ratios
• Mainly include
 Bone marrow aspirates – either whole
(BMA) or concentrated (BMAC)
Adipose stromal vascular fractions (A-
SVF)
Tissue “micrograft.”
•The major limitation of this approach is
that mesenchymal stem (and progenitor)
cells (MSCs) represent a very limited
fraction of the implanted cells.
• Exponentially increase the number
of cells of a specific phenotype, that is,
uncommitted or committed
•source of uncommitted MSCs : bone marrow
(BMSCs), adipose tissue (ASCs) & dental tissues
•Sources of committed c ells :Periosteum &
cancellous bone/marrow of the alveolar bone
•The major limitation of ex vivo expansion
strategies is the need for highly sophisticated
laboratories.

• A recent clinical trial evaluated the regenerative effects of systemic
delivery of teriparatide, a recombinant form of parathyroid hormone (PTH).
• The study demonstrated a periodontal anabolic effect favoring a
regenerative outcome. Following periodontal surgery, teriparatide was
systemically delivered for 6 weeks and results compared with a placebo
control.
• Delivery of this recombinant molecule in this fashion was associated with
improved clinical outcomes, including greater resolution of alveolar bone
defects and accelerated osseous wound healing (Bashutski et al. 2010).

Methods for gene delivery in periodontal applications
• The delivery method can be tailored to the specific characteristics of the
wound site.
• For example, a horizontal one- or two-walled defect may require the use of a
supportive carrier, such as a scaffold.
• Other defect sites may be conducive to the use of an adenovirus vector
embedded in a collagen matrix.

Two main strategies of gene vector delivery have been applied to
periodontal tissue engineering.
Gene vectors can be introduced to the target site through :
• In vivo gene transfer involves the insertion of the gene of interest directly
into the body anticipating the genetic modification of the target cell.
• Ex vivo gene transfer includes the incorporation of genetic material into
cells exposed from a tissue biopsy with subsequent re-implantation into the
recipient.

Cell‐ and gene‐based technologies using scaffolding matrices for periodontal tissue
engineering
Carranza, 13th ed

Scaffold fabrication technologies
• Direct 3D printing, stereolithography, selective laser sintering and fused
deposition modeling are some of the common techniques used to fabricate
scaffolds ranging from millimeter to nanometer size scale.
• Pathological or trauma induced damage to periodontal tissues can be
potentially be treated by inducing bone-ligament complex regeneration using
tissue engineered scaffolds.
• The use of faster resorbing polymers such as polylactic-coglycolic acid and
gelatin as scaffolds with a highly porous structure has been shown to result in
improved vascularization and tissue ingrowth.
• The use of scaffolds that can provide biomechanical cues that allow for
perpendicular alignment of periodontal fibers to the root surface, provide
osteogenic cues and suitable space for bone regeneration and transport and
stabilize cells capable of cementogenesis onto the root surface.

Future perspectives: targeted gene therapy in vivo
• Developments in scaffolding matrices for cell, protein and gene delivery have
demonstrated significant potential to provide smart biomaterials that can
interact with the matrix, cells and bioactive factors.
• The targeting of signaling molecules or growth factors (via proteins or genes) to
periodontal tissue components has led to significant new knowledge generation
using factors that promote cell replication, differentiation, matrix biosynthesis
and angiogenesis.
• To achieve improvements in the outcome of periodontal-regenerative medicine,
scientists will need to examine the dual delivery of host modifiers or anti-
infective agents to optimize the results of therapy.

Factors That Influence Therapeutic Success
(1) The selection of the appropriate surgical technique, accurate assessment of
the periodontal defect, and the clinician's clinical experience
(2) The importance of the tooth in the overall restorative treatment plan
(3) The patient‘s selection of the regenerative options

Reconstructive Periodontal Surgery
-Oinam Monica Devi
MDS Second Year
(PART-2) MATERIALS

Introduction
• The use of barrier membrane dates back to early 1950s for the periodontal
regeneration procedures.
• A bone graft is defined as a living tissue capable of promoting bone healing,
transplanted into a bony defect, either alone or in combination with other materials.
• Bone grafts consist of materials of natural or synthetic origin, implanted into the
bone defect site, documented to possess bonehealing properties.
• For GTR and GBR techniques, whether or not the graft material is filled, a special
barrier membrane plays a key role to prevent epithelial or undesirable tissues
migration into the defective area , and consequently it allows sufficient time for
bone, cementum, and periodontal ligament regeneration.

BARRIER MEMBRANES
Use of GTR membrane for covering the bone defect

• Periodontal regeneration by membrane techniques is based on the principal of
separation of different tissues by surgical placement of physical barriers.
• Soft tissue turnover rate is faster than bone and periodontal tissue formation,
using barrier membranes allows for defect space to be maintained for
regenerating tissues which would otherwise be infiltrated and occupied by the
epithelial cells.
• Membranes exclude unwanted epithelial cells, provide space for appropriate cells
(i.e., PDL cells, bone cells, and/or cementoblasts), and increase blood-clot
stability in order to improve the outcome of periodontal regenerative procedures.

• Barrier membranes were used with two main goals.
1. To create a barrier between the soft and the hard tissues following the
competition theory.
2. The mechanical ability of a membrane to separate the forces applied to
the soft tissues from the underlying graft augmenting the stability of the latter.

Wide and non-supportive defects
Self-supporting membranes or with bio-
resorbable barriers supported with a
filler material
Wide and non-supportive defects (2
wall)
Bio-resorbable barrier is suggested,
assuming that the residual walls in a
narrow defect would prevent the
collapse of the barrier and the soft
tissues
Treatment of intrabony defects using membrane
Rationale is to avoid as much as
possible the collapse of the
barriers and of the overlying soft
tissues into the coronal part of the
defect

During the course of GBR evolvement, a set of requirements for the membrane
has been defined (Dahlin, 2010):
(a) Biocompatibility: The interaction between the material and the tissues should not
adversely affect the surrounding tissues, the intended healing result or patient safety.
(c) Space-making capacity: The membrane should provide a suitable space in which the
regeneration of bone can take place.
(d) Attachment to or integration with the surrounding tissues: The integration of the
membrane with the tissues stabilizes the wound healing environment and contributes to
the creation of a barrier between the soft tissue and the bone defect.
(e) Manageability: The membrane must be clinically manageable.
(b) Occlusive properties: The material should prevent soft tissue invasion and provide some
degree of protection from bacterial invasion if the membrane becomes exposed to the
oral environment;

Non-degradable barrier membranes
• Materials such as cellulose acetate laboratory filters (Millipore®) ,silicone sheets ,and
expanded polytetrafluoroethylene (ePTFE) laboratory filters , were the first non-
degradable biomaterials used for investigating barrier membranes for regenerative therapy.
• The function of non-degradable membranes is temporary as they maintain their structural
integrity upon placement and are later retrieved via surgery.
• Its use gives the clinician greater control over the length of time the membrane will remain
in place.
• The retrieval procedure increases the risk of surgical site morbidity and leaves the
regenerated tissues susceptible to damage and post-surgery bacterial contamination.
• Membrane exposure due to flap dehiscence during healing is also a frequent post-surgical
complication.

• e-PTFE has a porous structure that allows tissue ingrowth.
• PTFE is exposed to high tensile stresses to expand and to create a porous
microstructure.
• Characteristics of e-PTFE are its biocompatibility and resistance to enzymatic
degradation by the host and microbes.
• A nonporous synthetic polymer is d-PTFE that does not allow ingrowth of
tissue.
• The integration of titanium provides a non-resorbable, biocompatible material
with high strength and rigidity, resistant to corrosion for the purpose of
increasing mechanical stability, maintaining a larger area of space and
preventing the collapse of the barrier membrane.

• Barrier membranes used alone without particulate graft materials for guided regeneration
applications are associated with membrane compression/collapse into the defect space
by overlying soft tissue pressure.
• To overcome this, membranes have been developed using stiff materials such as titanium
membranes or metal reinforced expanded-polytetrafluoroethylene
(ePTFE) for the treatment of complex vertical periodontal defects.
• The plasticity of titanium based membranes permits bending and adaptation to any bony
defect shape.
• The commonly available and used titanium based mesh/membranes are the
Frios®BoneShields, which is 0.1 mm thick and has a pore diameter of 0.03 mm.

• The common feature of the commercially available titanium membranes is the
macroporosity which plays a critical role in maintaining blood supply and is
thought to enhance regeneration by improving tissue integration & wound
stability .
• The tissue integration of titanium membrane can result in membrane removal
difficult at the second surgery.
• Another problem associated with use of titanium membranes in guided
regeneration therapy is the fibrous ingrowth and exposure of the membrane.
• Development of less porous and micropore-sized titanium membranes could
provide with improved clinical results.

• Polytetrafluoroethylene (PTFE) is a non-porous inert and biocompatible fluorocarbon
polymer.
• Two non-resorbable PTFE based barrier membranes that are commonly used are
1. The expanded-polytetrafluoroethylene (e-PTFE)
2. The titanium-reinforced high density polytetrafluoroethylene (Ti-d-PTFE)
• When there is a clinical requirement that requires larger areas of space maintenance, Ti-d-
PTFE can be used as it is stiffer due to the central portion of the membrane reinforced
with titanium to prevent collapse.
• The Ti-d-PTFE has also smaller pore size that does not allow bacterial ingrowth into the
graft material if left exposed.
• An alternative approach is using a double layer of PTFE membrane with a titanium
framework interposed (Cytoplast® Ti-250) which has shown to be successful for ridge
augmentation and treatment of large defects in the alveolar process.

PTFE and modifications
• PTFE membranes have the advantage of not eliciting any immunological reaction and
being resistant to breakdown by the host tissues.
• Compared with biodegradable membranes, they have superior space-making capability,
mainly when these membranes have titanium reinforcement, which makes them
• the ideal membranes for vertical bone regeneration.
• Their main limitation is the increased frequency of membrane exposure with a
subsequent risk for bacterial contamination and infection.
• Other limitation is the difficulty in their removal due to their soft tissue integration.
• The cost of PTFE membranes is higher compared to biodegradable membranes.

Advantages:
• Simple removal since there is no tissue ingrowth
• Particularly useful when primary closure is impossible without tension, such as
alveolar ridge preservation, large bone defects, and the placement of implants
immediately after extraction.
• Membranes can be left exposed and thus preserve soft tissue and the position
of the mucogingival junction.
• No need for extensive releasing incisions to obtain primary closure.
Disadvantage: Tendency for collapse of membrane towards defect
Even when the membrane is exposed to the oral cavity, microorganisms are
excluded by the membrane while oxygen diffusion and transfusion of small
molecules across the membrane is still possible.

•More effective than surgical debridement in correcting intrabony defects.
 Gains in clinical attachment level (3 to 6 mm)
 Improved bone levels (2.4 to 4.8 mm)
 Probing depth reductions (3.5 to 6 mm).
(Becker W et al 1988, Claffey N et al 1989, Cortellini et al 1993,1994,1996, Tonetti M et al
1993)

Metals
• Properties of titanium are biocompatibility, high strength, rigidity for space maintenance,
low density& weight, the ability to withstand high temperatures, and resistance to corrosion.
• The use of titanium for GBR was inspired from a successful outcome of using a titanium
mesh for reconstruction of maxillofacial defects.
• Titanium mesh alone or with bone substitutes is a procedure for localized alveolar ridge
augmentation prior to, or simultaneously with, implant placement.
• Occlusive titanium and micro-perforated titanium membranes have also been introduced and
used for treatment of peri-implant bone defects and ridge augmentation.
• Their limitations include difficulties in their removal due to connective tissue integration,
mainly associated with the titanium mesh.
• Lack of tissue integration has been reported with the use of solid titanium materials.
Naturally derived non degradable membrane

Biodegradable barrier membranes
• Clinical studies in the early 1990s reported the successful use of degradable membranes for
GBR therapy.
• The main factors influencing safety and the effectiveness of degradable membranes are the
degradation end-products and their fate.
• It is important for the design of degradable membranes to be such that it maintains the
functional characteristics for an adequate healing period.
• Biodegradable barrier membranes are mostly incapable in maintaining defect space on their
own due to their lack of rigidity especially when exposed to oral fluids &/or blood, so they
are mostly used in combination with autogenous or synthetic bone grafts substitutes.

Natural degradable barrier membranes
• They are fabricated mostly using collagen from tissues from human or animal sources.
• A major advantage over nonresorbable barrier membranes is that resorbable membranes
do not require an additional surgery for membrane removal, therefore decreasing patient
morbidity, time, and cost.
• A major obstacle that resorbable membranes face is the unpredictable resorption time and
degree of degradation.

Collagen (non-crosslinked)
• Collagen-based membranes are the most commonly used naturally derived membranes
for GBR and their degradation does not exert any potential deleterious effect to the
tissues.
• Collagen membranes can be used alone for alveolar bone defects which do not require
extra fixation and stability such as bone dehiscence and fenestration defects.
• Their main limitation is their lack of rigidity, which limits their space-making
capabilities and requires their combination with a scaffold.
• Since their degradation is fast they may not meet the duration of time required for
optimal tissue regeneration.

• Collagen membranes allow for good tissue integration, fast vascularization,
hemostasis, and chemotaxis for periodontal ligament fibroblasts and gingival
fibroblasts.
• Collagen membranes have been shown to stimulate fibroblast DNA synthesis and
osteoblasts show improved adherence to collagen membrane surfaces in
comparison to other barrier membrane surfaces.
• The biodegradation of collagen membranes is accomplished by endogenous
collagenases into carbon dioxide and water.
• BioMend® is a biodegradable barrier membrane fabricated from Type-I collagen
derived from bovine achilles tendon. The membrane is semi-occlusive, having a
pore size 0.004 μm and resorbs in 4 to 8 weeks after implantation.

• Limitations of collagen membranes include poor mechanical properties and therefore
susceptibility to collapse and loss of space-maintaining ability.
• The resorption of collagen membranes is dependent upon the source of material (bovine,
porcine, human) and the breakdown rate of collagen into oligopeptides and amino acid
molecules.
• Collagen membranes are absorbed through enzymatic degradation by collagenases/proteases
and macrophage/polymorphonuclear leukocyte-derived enzymes and bacterial proteases.

Chemically modified collagen
• In order to slow down the bio-absorption process of collagen membranes, a number of
different methods of physical/chemical cross-linking have been developed, which may
also enhance the membrane mechanical properties.
• Although chemical cross-linking has resulted in improvement of collagen stability,
release of chemicals residues (e.g., amides or aldehydes) has been associated with severe
inflammation at the implantation site.

• Cross-linked membranes showed a better level of vascularization in defects
in comparison with non-cross-linked membrane or with empty defects
(Bubalo M et al 2013, Dubovina D 2014).

Chitosan, alginate
• Chitosan is a polysaccharide comprising of copolymers of glucosamine and N-
acetylglucosamine .
• It has good biocompatibility and degradation appears to have no toxicity.
• It has bacteriostatic properties, the ability to inhibit growth of gram-negative and
grampositive bacteria, Actinobacillus actinomycetemcomitans and Streptococcus-
mutans.
• Their material properties include biocompatibility, biodegradability, low
immunogenicity and a bacteriostatic effect.

Synthetic degradable barrier membranes
• The most commonly used biomaterials used to fabricate synthetic degradable barrier
membranes are the poly-α-hydroxy acids, which include polylactic polyglycolic acid and
their copolymers.
• The advantage of using polyhydroxy acids are that they undergo complete hydrolysis to
water and carbon dioxide, which allows for complete removal from the implantation site.
• The degradation rate varies depending on the presence glycols and lactides in the
constitutional makeup.

• Guidor® is a double-layered resorbable barrier membrane composed of both polylactic
acid and a citric acid ester known as acetyl tributylcitrate.
• The external layer of the barrier membrane is designed with rectangular perforations
allowing the integration of the overlying gingival flap.
• This surface design successfully promotes tissue integration and only limited gingival
recession after usage has been reported.
• Between the internal and external layers, internal spacers are present that create space for
tissue ingrowth.
• The internal layer has smaller circular perforations and outer spacers for maintaining the
space between the membrane and the root surface.

Synthetic polymers
• The main advantages of polymeric membranes are their manageability, process
ability, tuned biodegradation and drug-encapsulating ability.
• Their degradation might elicit a strong inflammatory response, leading to resorption
of the regenerated bone.
• The resorption rate of these types of membranes is largely dependent on the type of
polymer used.

• Epi-Guide® is a porous three-layered and threedimensional barrier membrane
fabricated using polylactic acid polymers (D, D-L, L polylactic acid) and is
completely resorbed in 6–12 months.
• The three-layered construction of the membrane attracts, traps, and retains
fibroblasts and epithelial cells while maintaining space around the defect.
• Epi-Guide® is a self-supporting barrier membrane and can be used situations
without support from bone grafting materials
In a multicentre study including 40 patients with bilateral Class II furcations defects,
Vernino et al., 1998 examined the influence of Epi-Guide® and Guidor on the
regeneration of hard tissues. The results showed significantly better results for of Epi-
Guide® with regard to the reduction of the vertical component of the intrabony defect.

Platelet Rich Fibrin
Membrane:
Biopolymer Fibrin
Potent source of
growth factors
Rapid degradadtion
within 2 weeks or less
Amniotic Membrabe:
Thin (300nm), though, transparent,
intimately moldable asvascular composite
membrane composed of three layers:
Epithelial Layer, Basement Membrane,
Connective Tissue Matrix
Mechanisms of Healing Include:
Immunomodulatory, Antimicrobial,
Reduction of pain, Antiscarring,
Antiinflammatory, Revascularization

• The membrane, the main component of GBR, can be improved depending on the
functional requirements and the involved biological mechanism.
• These modifications may include the following:
(a) Optimizing the physicochemical and mechanical properties, for example, the porosity,
structure, thickness, rigidity and plasticity
(b) Incorporating biological factors and synthetic bioactive materials
(c) Incorporating antibacterial agents and antibiotics

Graft-Associated Reconstructive Procedures
of Historical Interest
1.Sclera
• Previously used in periodontal procedures because it is a dense, fibrous
connective tissue with poor vascularity and minimal cellularity.
• Low incidence of antigenicity
• Barrier to apical migration of the junctional epithelium
• Protect the blood clot during the initial healing period.
It does not appear to induce osteogenesis or cementogenesis

2. Cartilage
• Cartilage has been used for studies in monkeys and treatment of periodontal
defects in humans serving as a scaffold for new attachment.
• It is not used today in periodontal therapy.
3. Plaster of Paris
• It is biocompatible and porous, thereby allowing fluid exchange, which prevents
flap necrosis.
• Plaster of Paris resorbs completely in 1 to 2 weeks.
• It does not induce bone formation.
4. Plastic Materials
• Hard tissue replacement(HTR) polymer is a nonresorbable,microporous,
biocompatible composite of polymethylmethacrylate &
polyhydroxyethylmethacrylate.
• Histologically, this material is encapsulated by connective tissue fibers, with no
evidence of new attachment.

5. Bioactive Glass
• It consists of sodium and calcium salts, phosphates, & silicon dioxide.
• 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.
6. Coral-Derived Materials
• Two different coralline materials have been used in clinical periodontics: natural
coral and coral-derived porous HA which are both biocompatible.
• Both materials have demonstrated microscopic cementum and bone formation,
but their slow resorbability or lack of resorption has hindered clinical success in
practice.

7. Calcium Phosphate Biomaterials
• Calcium phosphate biomaterials have excellent tissue compatibility and do not
elicit any inflammation or foreign body response.
• These materials are osteoconductive; act as a scaffold for blood clots to be
retained to allow bone formation.
• Two types of calcium phosphate ceramics have been used, as follows:
I. Hydroxyapatite (HA) has a calcium-to-phosphate ratio of 1.67, similar to that
found in bone material & is generally nonbioresorbable.
II. Tricalcium phosphate (TCP), with a calcium-to-phosphate ratio of 1.5, is
mineralogically B-whitlockite & is partially bioresorbable.
• Histologically these materials appeared to be encapsulated by collagen.

BONE GRAFTS
• The use of bone grafts for reconstructing intra-osseous defects produced by periodontal
disease dates back to Hegedus in 1923.
• It was then revived in 1965 by Nabers and O’Leary.
• Buebe and Silvers (1936) used boiled cow bone powder to successfully repair
intra-bony defects in humans.
• Force berg (1956) used Ox purum in 11 human intra-bony defects.
• According to the US Food and Drug Administration (USFDA), bone grafts are
classified as Class II devices (bone grafts filling the bony voids and defects) and Class
III devices (bone graft containing drugs).

• The rationale behind the use of bone grafts (Urist 1980; Brunsvold & Mellonig 1993):
(1) Contain bone‐forming cells (osteogenesis)
(2) Serve as a scaffold for bone formation (osteoconduction)
(3) The matrix of the bone grafts contains bone‐inducing substances (osteoinduction)

• A Bone graft should meet specific requirements to achieve its goal.
1. An interconnected porosity with an adequate pore size (100-300 μm) should allow for
diffusion throughout the whole bone graft for bone cells, nutrients and exchange of waste
products.
2. A surface that allows vascular ingrowth, bone cell attachment, migration and proliferation.
3. Adequate mechanical compressive strength and elasticity for allowing absorbance of the load
from surrounding hard and soft tissues in non-contained defects.
4. 4. Controlled biodegradability, which ensures resorption during the tissue-remodellingprocess
while maintaining defect volume for bone ingrowth.
5. 5. Sufficient dimensional stability for allowing the chairside adaptation of the bone graft to
the defect.

Biomaterials used as bone replacement grafts must meet specific requirements
to achieve the goal of developing a new and healthy bone tissue formation:
BIOCOMPATIBILITY
• Interaction between the material and the
tissues should not adversely affect the
surrounding tissues.
•Should be inherently bioactive in
promoting the bone regeneration process
SURFACE PROPERTIES
•Important for protein adsorption,
extracellular matrix deposition,
cell adhesion, differentiation,
migration and finally bone
formation.
OSTEOCONDUCTIVITY/ OSTEOINDUCTIVITY
• Osteoconduction: should allow for bone growth
directly in contact with the
biomaterial surface from the surrounding bone
• Osteoinduction: capable of recruiting mesenchymal-
type osteoprogenitor cells &
transforming an undifferentiated mesenchymal cell
into a mature, bone-forming osteoblast.
POROSITY
•An adequate pore size (100-300 μm) ,
morphology and inter-connectivity is
needed to allow for diffusion throughout
the whole scaffold of bone cells, nutrients
and exchange of waste products.

BIODEGRADIBILITY
•The ideal bone graft substitute is expected to
be fully replaced by bone, preferably at a
predictable absorption rate, without losing
tissue volume and without interfering with the
healing and regeneration process.
MECHANICAL PROPERTIES
•Ideally, the compressive strength and
elasticity of the biomaterial should be at
least those of the natural bone at the site
of regeneration.
ANGIOGENECITY
•The inherent biomaterial properties (e.g.,
porosity and surface) should promote
angiogenesis and the appropriate
vascularization of the graft volume.
HANDLING
• Should be cohesive and dimensionally
stable, and easy for chairside use to adapt
to the defect.
MANUFACTURING PROCESSES
• Should be provided with certification or documentation of the appropriate
manufacturing and sterilization processes and assure long shelf time and
reduced production costs.

Classification of Bone Graft
• Based on the type of graft used
 Particulate
 Putty
 Block
• Based on the Source
 Autograft
 Allograft
 Xenograft
 Alloplast
• Based on Bone Graft Substitutes (Laurencin)
 Allograft based
 Factor based
 Cell based
 Ceramic based
 Polymer based.

• Allograft Based
 Allograft bone used alone or in combination
 For example: allegro, orthoblast, graft-on
 Action: osteoconductive, osteoinductive
• Factor Based
 Natural and recombinant growth factor used alone or in combination
 For example: Transforming growth factor-beta,platelet-derived growth factor,
fibroblast growth factor, BMP
 Action: Osteoinductive, osteoinductive, and osteoconductive with carrier materials.

• Cell Based
 Cells used to generate new tissue alone or seeded onto a support matrix
 For example: Mesenchymal stem cells
• Action: osteogenic, both osteogenic and osteoconductive with carrier materials
• Ceramic Based
 Includes calcium phosphates, calcium sulfate, and bioactive glass used alone or in
combination
 For example: Osteograft, osteoset, Novabone
• Action: Osteoconductive, limited osteoinductive when mixed bone marrow
• Polymer Based
 Includes degradable and nondegradable polymers used
 For example: Cortoss, OPLA, Immix
• Action: Osteoconductive, bioresorbable in the degradable polymer.

Classification of bone graft and substitute materials used in dentistry, broadly
classified into five categories and showing their associated sub-categories.

1. Cancellous grafts stimulate osteogenesis giventhe presence of osteoblasts, osteocytes
and mesenchymal stemcells within its structure.
2. Stability is mainly provided by cor-tical grafts which are significantly deficient in
osteogenic ability,exhibit extended absorption while new bone growth is very slow.
3. A combination of cortical and cancellous grafts can ensure stabilityand osteogenesis.

Ideal Requisites of Bone Grafts
• Osteoinductive property
• Non-toxic
• Resistant to infection
• No root resorption or ankylosis
• Non-antigenic and biologic compatibility
• Easily adaptable and available
• Predictability
• Strong and resilient
• Require minimal surgical intervention
• Rapid vascularization
• Should stimulate new attachment and be able to trigger
• osteogenesis.

Commercially available bone grafts

Autogenous graft
• Autogenous bone is harvested from a donor site in the same individual and
transplanted to another site.
• “Autogenous bone is still the gold standard and accelerates initial bone formation to
a greater extent than bone substitutes”(Yamada & Egusa, 2018).
• It has been considered the gold standard because it acts as scaffold, and it has
osteoconductive, osteoinductive, and osteogenic properties.
• It has no potential complications of histocompatibility.

• Autografts possess the essential components to achieve (Amini et al., 2012).
1. Osteoinduction
2. Osteogenesis
3. Osteoconduction
• Autogeneous graft can be obtained either intraorally or extraorally.

1.Cortical bone chips Nabers and O’ Leary (1965)
• Reported a coronal increase in bone height by using cortical bone chips
• Bone obtained by hand chisels during osteoplasty and ostectomy.
•Disadvantage
• Relatively large particle size 1,559.6 × 183 um
• The dense cortical matrix results in relatively slow revascularization and
incorporation,
• Potential for sequestration
• As resorption must occur before the deposition of new bone, and limited perfusion
make this option poorly osteogenic.

2. Osseous Coagulumm (Robinson et al. 1969)
• Mixture of bone dust / shaving (small particles ground from cortical bone) and blood
• Carbide bur #6 or #8 at speeds between 5000 and 30,000 rpm
• Placed in a sterile dappen dish and mixed with the patient’s blood
• It is an extension of the technique developed by Nabers and O’Leary (1965).
• Robinson claimed significant fill in three-wall defects but unpredictable repair of one-
and two-wall osseous defects.
Advantage-
1. Small particle size provides additional surface area for the interaction of cellular and
vascular elements.
2. Ease of obtaining bone from an area already exposed during surgery.

3.Bone Blend
(Diem and colleagues, 1972)
• Permit easier access and collection of donor material
• The bone spicules (cancellous and cortical), obtained with
chisels and rongeurs, were triturated in Sterile capsule and
pestle for 60 seconds to produce a homogeneous slushy
osseous mass
• Easily placed in a bony defect and firmly packed inside
• The final particle size is about 210 × 105 um
• Froum and colleagues (1976) found this provided the same regenerative potential as
did iliac marrow and significantly greater regenerative potential than that of open
débridement.

4. Cancellous Bone Marrow Transplants
• Cancellous bone can be obtained from the
– Maxillary tuberosity
– Healing sockets
– Edentulous areas
 Autogenous cancellous bone with hematopoietic marrow has the maximum osteogenic
potential.
 Least chance of host rejection
 Porous consistency of cancellous bone increases the potential for rapid
revascularization and subsequent graft survival.

5. Bone Swaging/ Contiguous transplant Ewen (1965)
• Bone from an edentulous area was moved next to the tooth to get rid of the defect.
• This required that the bone to be fractured, without completely severing it to maintain
the blood supply, and at the same time be moved next to the tooth
Disadvantage
• Impractical technique
• Further limited by the need for an adjacent edentulous ridge and bone quality that
permits bending without fracturing.

• Disadvatages :
1. Biological cost of harvesting bone from a second donor site leading to higher
morbidity, increased surgical time, and risk of graft contamination.
2. The resorption of these bone replacement grafts is higher, and their rate of
resorption is not predictable.
3. Limitations in terms of volume availability, mainly when harvesting from
intra-oral sources, mainly in a block form may be difficult to adapt to the
anatomy of the defect.
Autografts may not be a treatment option when the defect site requires large amounts of bone.

This systematic review and meta-analysis included RCTs comparing a combination of EMD with
autogenous bone graft and EMD alone for the treatment of intrabony periodontal defect with a follow-up
of 6 months. Standard difference in means between test and control groups as well as relative forest plots
were calculated for clinical attachment level gain (CALgain), probing depth reduction (PDred), and
gingival recession increase (RECinc).
Three RCTs reporting on 79 patients and 98 intrabony defects were selected for the analysis.
Statistical heterogeneity was detected as significantly high in the analysis of PDred and REC inc (I2 =
85.28%, p = 0.001; I2 = 73.95%, p = 0.022, respectively), but not in the analysis of CAL gain (I2 =
59.30%, p = 0.086).
Standard difference in means (SDM) for CALgain between test and control groups amounted to -0.34 mm
(95% CI -0.77 to 0.09; p = 0.12). SDM for PDred amounted to -0.43 mm (95% CI -0.86 to 0.01; p =
0.06). SDM for RECinc amounted to 0.12 mm (95% CI -0.30 to 0.55. p = 0.57).
Within their limits, the obtained results indicate that the combination of enamel matrix derivative and
autogenous bone graft may result in non-significant additional clinical improvements in terms of
CALgain, PDred, and RECinc compared with those obtained with EMD alone..
The Efficacy of Bone Replacement Grafts in the Treatment of Periodontal Osseous
Defects. A Systematic Review (Reynolds M A et al., 2014)

Allografts
• Bony tissue that is harvested from one individual and transplanted to a genetically
different individual of the same species.
• Available forms
 Demineralized bone matrices
 Cancellous chips
 Cortico-cancellous
 Cortical grafts
 Osteochondral
 Whole-bone segments

• There are three main divisions:
1. Frozen:
 Frozen at −800 C to avoid degradation by enzymes
 Acellular
 Possess the highest osteoinductive and osteoconductive properties due to the presence of
BMPs
 Disease transmission and high immune response
2. Freeze-dried:
 Dehydration & freezing without demineralization, leading to decreased antigenicity
 Only osteoconductive potential
3. Freeze-dried demineralized
 After dehydration, the inorganic part of the bone is eliminated, leaving only the organic
part that contains BMPs
 Undergo resorption at a quick rate
 Osteoconductive and inductive features
• Produce less amount of vital new bone in comparison to autografts

Limitations
1. Allografts are associated with risks of immunoreactions and transmission of infections.
2. Devitalized (and often sterilized) mainly through decalcification, deproteinization,
irradiation and/or freeze-drying processing and have reduced osteoinductive
properties.
3. High failure rates over long-term use.

(Reynolds MA et al., 2003)
This systematic review was conducted to assess the efficacy of bone replacement grafts compared to surgical
debridement alone on clinical, radiographic, adverse, and patient-centered outcomes in patients with periodontal osseous
defects.
For purposes of meta-analysis, change in bone level (bone fill) was used as the primary outcome measure, measured
upon surgical re-entry or transgingival probing (sounding).
With respect to the treatment of intrabony defects, the results of meta-analysis supported the following conclusions: 1)
bone grafts increase bone level, reduce crestal bone loss, increase clinical attachment level, and reduce probing depth
compared to open flap debridement (OFD) procedures; 2) No differences in clinical outcome measures emerge between
particulate bone allograft and calcium phosphate (hydroxyapatite) ceramic grafts; and 3) bone grafts in combination with
barrier membranes increase clinical attachment level and reduce probing depth compared to graft alone.
With respect to the treatment of furcation defects, 15 controlled studies provided data on clinical outcomes. Outcome
data from these studies generally indicated positive clinical benefits with the use of grafts in the treatment of Class II
furcations.
With respect to histological outcome parameters, 2 randomized controlled studies provide evidence that demineralized
freeze-dried bone allograft (DFDBA) supports the formation of a new attachment apparatus in intrabony defects, whereas
OFD results in periodontal repair characterized primarily by the formation of a long junctional epithelial attachment.
Multiple observational studies provide consistent histological evidence that autogenous and demineralized allogeneic
bone grafts support the formation of new attachment. Limited data also suggest that xenogenic bone grafts can support
the formation of a new attachment apparatus. In contrast, essentially all available data indicate that alloplastic grafts
support periodontal repair rather than regeneration.
Bone replacement grafts provide demonstrable clinical improvements in periodontal osseous defects compared to
surgical debridement alone.

Toscano N et al., 2010; Nevins M et al,2014

Alloplast
• They are synthetic products that provide no risk of infections and are easily available,
biocompatible, and have osteoconductive properties.
• Bioceramics have a similar structure to the inorganic bone component.
• Absorbable/non-resorbable hydroxyapatite is biologically inert and biocompatible. It acts as a
filler, does not contribute to bone formation, and has a slow resorption rate.
• Bioglass materials are made of a glassy ceramic, zinc oxide, and calcium oxide, they also
have osteoconductive properties but are hardly resorbed.
• Polylactic acid polymers are also available for use in periodontal regeneration. They are
biocompatible and biodegradable.

• Alloplasts are biocompatible and readily available
1. Able to serve as a framework for new bone formation
2. Resorbable in the long term and have the potential for replacement by host bone
3. Radiopaque
4. Available in particulate and molded forms and Easy to manipulate clinically
5. Not support the growth of oral pathogens
6. Have surface electrical activity (i.e., be charged negatively)
7. Microporous and provide added strength to the regenerating host bone matrix, and permit
biological fixation
8. Nonallergenic
9. Adapt to be effective in a broad range of medical situations (e.g., cancer, trauma, and
infective bone destroying diseases)
10. Have a surface that is amenable to grafting
11. Act as matrix or vehicle for other materials (e.g., bone protein inducers, antibiotics, and
steroids)
12. Clinical results are encouraging for these materials based on their biocompatibility,
enhancement of clinical attachment levels, reduction of probing depths, and hard
tissue fill of the intra-bony defects.

Advantages
• Regeneration and reconstruction of the attachment apparatus is possible
• By reconstructing the periodontium (lost bone, cementum, and periodontal Ligament), it
is possible to reverse the disease process
• Increased tooth support
• Improved function
• Enhanced aesthetics.

Disadvantages
1. Increased treatment time
2. Increased postoperative care
3. Variability in repair and predictability
4. Greater expense
5. Availability.

Various types of alloplasts are:
1. PMMA and polyhydroxyethyl-methacrylate (PHEMA) polymers:
• A biocompatible micro porous polymer containing PMMA, PHEMA and calcium
hydroxide is available as a bone grafting material for the treatment of periodontal
defects (HTRTM Synthetic Bone-Bioplant, Norwalk, CT).

2. Demineralized dentin matrix:
• Organic component of dentin, which accounts for approximately 20% of dentin
weight, is mainly type I collagen, a component of bone.
• BMPs promote the differentiation of mesenchymal stem cells into chondrocytes,
and thus enhance bone formation.
( D’Alessandro et al. 2017 ) : Successful osseointegration and new bone formation
observed surrounded by vascular connective tissue, 4 months following placement
of SmartBoneTM graft.

3. Hydroxyappatite (HA) :
• HA based grafts form a chemical bond directly to bone once implanted .
• Synthetic HA is available and used in various forms: 1) Porous nonresorbable;
• 2) Solid non-resorbable; and 3) Resorbable (non-ceramic, porous)
• HA is non-osteogenic and mainly functions as an osteoconductive graft material.
• Synthetic HA can be found as porous or nonporous and in ceramic or nonceramic forms.
Dewi A H et al., 2018: This systematic review conducted for the use of
hydroxyappatite bone substitute grafting for alveolar ridge preservation, sinus
augmentation, and periodontal bone defect . It was reported that HA bone substitute
interferred with with the normal healing process, with significant differences found
for sinus augmentation but not for periodontal bone defects.

• The advantages of using HA are:
(1) Immunoreactions can be ignored
(2) Postoperative morphologic changes and volume decreases do not occur if
small blocks and chips are adequately packed during surgery
(3) Postoperative absorption of HA, if any, is slight and slow and is replaced by
bone
(4) Cement fixation performed on a layer of HA particles prevents the harmful
influence of polyethylene wear particles of cement interface.

• The clinical disadvantages of HA particles are that they tend not to stay in place
in a bleeding site.
• There is a relatively slow restoration of bone within the particles.
• The polycrystalline ceramic form of pure densely sintered HA is non-resorbable,
osteo-conductive has low microporosity and act primarily as inert biocompatible
fillers.
( Kamboj M et al. 2016 ) : Decreased periodontal pocket depth, decreased clinical
attachment loss, decreased intrabony defect depth, 6 months following placement of
OstimTM graft

4. Calcium phosphate cement (CPC):
• Calcium phosphate preparation to become available was synthetic hydroxyapatite in the
1970’s.
• CPCs are gaining special interest due to their biomimetic nature and potential use as
controlled release systems.

Dicalcium phosphates (DCP)
• These are acidic calcium phosphates that have a high solubility at physiological pH.
• Dicalcium phosphate dihydrate (DCPD or Brushite) are capable of regenerating bone in
atrophic alveolar ridges, buccal dehiscence defects and maxillary sinus floor elevation
procedures.
• Brushite grafts after implantation undergo phase conversion to insoluble HA which
ultimately limits their resorption rate and extent.
• Brushite can be used as precursor to the anhydrous form of DCP, dicalcium phosphate
anhydrous, also known as DCPA or monetite.

• Monetite does not convert to HA after implantation and resorbs at faster rates
compared to brushite cement grafts.
• Monetite granules have been compared with commercially available bovine HA (Bio-
Oss®), and has shown greater resorption and bone formation in the extraction sockets.
(Wakimoto, M et al. 2011): New bone formation with histological observation of
osteogenic activity surrounding MASTERGRAFT granules, 4-5 months following
graft placement.
(Kakar A et al. 2017) : New bone formation and minimal ridge width reduction
observed in post-extraction alveolar ridges of 15 patients.

Calcium polyphosphate (CPP)
• Calcium-Polyphosphate (CPP) is a good bone substitute as it can be made with
mechanical properties similar to trabecular bone, controlled degradability and shows
very good integration to host bone when implanted in vivo.
• CPP has been used in different forms, such as sintered porous blocks , particulates or
nanoparticles.
• CPP has promise as a biomaterial for biological and periodontal regenerative therapy.
(Sugawara A et al., 2002): Nearly complete bone regeneration in alveolar
ridge defects, 6 months following placement of CPC material.

5. β-tricalcium phosphate (TCP):
• Tricalcium phosphate is a porous calcium phosphate compounds.
• Alpha form is less stable than beta and forms the stiffer material calcium-deficient HA
when mixed with water.
• Examples of commercially available beta tri calcium phosphate graft material are
Synthograft™ (Bicon, Boston MA, USA) and Cerasorb® (Curasan Pharma GmbH,
Kleinostheim, Germany).
Ad De et al., 2011: Successful osseointegration and prominent bone formation along
graft surface evident 28 days after placement of OSferionTM

• TCP has two crystallographic forms; α-TCP and β-TCP..
• β-TCP exhibits good biocompatibility and osteoconductivity and is used commonly
as a partially resorbable filler allowing replacement with newly formed bone.
• Resorption of TCP grafts is thought to be dependent on dissolution by biological
fluids in the absence of osteoclasts around the materials and by presence of
osteoclast mediated resorption based on the osteoclast like giant cells in defect
areas in many studies.
• In terms of bone regenerative potential, β-TCP grafts have been shown to be similar
to autogenous bone, FDBA, DFDBA and collagen sponge.
• TCP biomaterials have been used in human clinical studies to repair periapical and
marginal periodontal defects, alveolar bony defects , alveolar ridge augmentation in
vertical and horizontal dimensions

7. Bioactive glasses (BG):
• It has capacity to form a carbonated HA layer on their surfaces once exposed to
simulated body fluids or implanted in vivo, hence the concept of “bioactivity.”
• These graft materials are composed of silicon dioxide, calcium oxide, sodium oxide,
and phosphorus pentoxide.
• The particle sizes of bioactive glasses (Bio-Glass®) range from 90 to 710 μm to 300–
355 μm.
• After implantation of bioactive glass, a silicon rich gel is formed on the bioactive
ceramic surface with the outer layer serving as a bonding surface for osteogenic cells
and collagen fibers.

• Limited true periodontal regenerative outcomes based on human histological analysis has
been demonstrated with the use of bioactive glass.
• Examples of BG which are commercially available are Perioglas® (Block Drug Co.,5 NJ,
USA) and Biogran® (Orthovita, PA, USA).
(Chacko N.L et al. 2014) : Decreases in periodontal pocketing depth, clinical
attachment loss, gingival recession, depth of bony defect observed, 9 months after
placement of PerioglasTM either alone, or in combination with a non-resorbable
membrane GoreTexTM or bioresorbable membrane Resolut AdaptTM.

6. Calcium sulfate:
• Calcium sulfate, generally known as plaster of Paris, or gypsum, is perhaps, the
oldest ceramic bone substitute material.
• These compounds have a compressive strength greater than that of cancellous bone.
• Calcium sulphate is usually applied as a barrier material to improve the clinical
outcomes of periodontal regeneration therapy.
• When used as a barrier, calcium sulphate materials work as an adjunct with other
graft materials.

• Currently, medical grade calcium sulphate impregnated with tobramycin is
commercially available (Osteoset®; Wright Medical Technology,
Arlington, TN, USA).
(Petruskevicius J et al. 2002) : Double-blind randomized trial 42% of bony defect
filled with new bone, 6 weeks after placement of OsteoSetTM graft. No
statistically significant additional bone formation observed during 3-6 months
period.

8. Oily CaOH2 Suspension:
• Non-setting oily CaOH2 suspension (OCHS; Osteo inductal R, Osteo inductal GmbH,
Munich, Germany) has been introduced for application in jaw bone surgery
9. Porous Titanium Granules:
• Tigran™ PTG (Natix, Tigran Technologies AB, Malmo, Sweden) is irregularly
shaped and porous Granules.
• The granules that have a porosity of about 80% and an osteoconductive surface structure
imitate properties of human bone, and create the scaffolding for bone generation that
stimulates osteoblast colonization and osseointegration.
• The granules are nonresorbable.
(Di Stefano D A et al. 2019 ) : Significant bone formation in alveolar ridge, 4 months
following placement of autograft with titanium mesh

10. Composite grafts:
• A “composite graft” contains osteogenic cells and osteoinductive growth factors along with
a synthetic osteoconductive matrix.
• Composite synthetic graft an alternative that can potentially unite the three essential
bone-forming properties in more controlled and effective combinations.
• A composite graft combines an osteoconductive matrix with bioactive agents that provide
osteo-inductive and osteo genic properties, potentially replicating autograft functionality.

(Eldibany R et al. 2014 ; Seifi M et al. 2015) : Studies in human subjects have found
that NanoBoneTM can preserve alveolar bone height at extraction sites. When used
with platelet-rich fibrin, it can accelerate bone regeneration and improve the quality
and quantity of newly formed bone following excision of mandibular cysts
• Potential composite grafts are bone marrow/synthetic composites, ultra porous
b-TCP/BMA composite, osteoinductive growth factors, and synthetic composites,
BMP/polyglycolic acid polymer composites and BMA/BMP/polyglycolic acid polymer
composite.

Xenografts
• Xenografts involve the transplantation of bone tissue across species.
• Bovine xenografts play a major role and have been proven for cranio-maxillofacial
applications with no reports on Transmissible Spongiform Encephalopathies (TSE) and
Bovine Spongiform Encephalopathy.
• The use of xenotransplantation presents a number of biological challenges:
1. Risk of disease transmission
2. An immune response of the host tissue after implantation
3. Lack of viable cells
4. Reduced osteoinductive properties due to manufacturing processes

Natural biomaterial
• The use of natural polymers for bone replacement can be elucidated due to their
similarity to the native extracellular matrix (ECM) and according to their chemical
composition.
• These polymers can be divided into three classes as follows:
(a) Proteins (collagen, gelatine, fibrinogen, elastin)
(b) Polysaccharides (glycosaminoglycans, cellulose, amylose)
(c) Polynucleotides (DNA, RNA)
• High osteoinductive properties
• Autologous ECM-based bone substitutes are highly biocompatible and display very little
risk of host immune reactions.
• Main limitation with their use is the need for an additional surgery to sample grafts with
associated morbidity & limited availability of tissue.

Synthetic polymers
• Synthetic polymers in bone tissue regeneration are aliphatic polyesters as their
copolymers and derivatives like
 Poly(lactic acid) (PLA)
 Poly(ε-caprolactone)
 Poly(glycolic acid)
 Poly(methyl methacrylate)
 Poly hydroxyl butyrate,Polyethylene
 Polypropylene
 Polyurethaneas
• These polymers are degraded by hydrolysis in vivo and have the advantage of being
easily tailored in different shapes, according to the mechanical demands in the particular
bone treated.
• Controllable and tuneable biomechanical and biodegradability properties.

• They still show some concerns about osteoconductivity, absorption timing
and local pH alterations.
• All polymers’ surfaces have the disadvantage of proving inferior cell
attachment properties.
(Prakash S et al. 2010 ): Reduction in periodontal probing depths, clinical attachment
gain and significant resolution of defects in alveolar crest bone, 6 months following
placement of Bioplant HTR Synthetic BoneTM.

Synthetic bioceramics
• Calcium sulphate, calcium phosphate (CaP) ceramics, bioactive glass and
combinations thereof are the most common synthetic bone substitutes available
at present.
• These bone grafts have compositional similarities to natural bone.

• When compared to metals and polymers, they are superior for bone repairs due
to their improved biocompatibility, bioactivity and strength.
• They have demonstrated the ability to partially integrate into natural bone tissue
and stimulate osteoblast differentiation, osteoblast growth and inorganic matrix
deposition.
• The use of CaP is motivated by the fact that the primary inorganic component of
bone is calcium hydroxyapatite, a subset of the CaP group.

• Mechanical properties are major disadvantages of synthetic bioceramics and
limit their use in load-bearing applications.
• The clinical applications of CaP bone substitutes are limited by their fragility, an
unpredictable absorption rate while not being able to maintain their defect
volume, which makes the CaP have overall less favourable clinical outcomes.

Combination of synthetic and xenograft bone
graft substitutes (xenohybrid)
• A very commonly used source of bone matrices is animal-derived bones;
bovine xenografts, distantly followed by equine and porcine, are commonly
used in clinical practice.
• Bovine-derived cancellous BGs are acknowledged as the closest xenograft to
human bone to be regenerated, second only to autografts.
• Xenografts are preferred as substitutes due to their clinical predictability.

• The ideal BG in the future will likely contain a combination of biomaterials with
varying features that can control
1. Mechanical properties
2. Pore morphology
3. Interconnective pores
4. Surface structure
5. Release of active bone-promoting biomolecules
6. Controlled biodegradability, which ensures resorption during the tissue-
remodelling process while maintaining the defect volume for bone ingrowth

• Bone tissue engineeing (BTE) strategies typically involve the presentation of physical
and/or biochemical signals to host or transplanted cells that are capable of responding to
these signals, activating and forming new bone tissue (Amini, Laurencin & Nukavarapu,
2012).
• Tissue regeneration is the process of renewal and growth to repair or replace tissue that
is damaged or suffers from a disease (Boisseau and Loubaton, 2011) .
• Tissue regeneration currently requires 3 main components: cells, scaffolds (matrices),
and signaling molecules such as growth factors.
• These components, with sufficient vascularization, wound stability, and time, each play
an important role in regeneration.
.

• Bioactive agents or factors are so called because they are natural mediators of
tissue repair capable of eliciting a response from a living tissue, organism or cell,
such as osteoblast differentiation, angiogenesis, matrix mitosis or the formation of
hydroxyapatite.
• The rationale behind the use of biological mediators is to regulate crucial cellular
events involved in tissue repair, including DNA synthesis, cell replication,
chemotaxis, differentiation, matrix synthesis, and tissue vascularization.

What are the critical biological phases characterizing
bone regeneration?
Alveolar bone regeneration follows a temporal series of events
1. Haemostasis and establishment of the blood coagulum
2. Inflammatory phase
3. Angiogenesis: cellular recruitment and capillary ingrowth
4. Mesenchymal cell recruitment, provisional non-mineralized matrix deposition
followed by interactive processes involving mineralization, bone-forming cell
differentiation and finally bone formation
5. Role of growth and differentiation factors
6. Processes of woven and lamellar bone formation
7. Remodelling of newly formed bone; coupling of osteoclasts and osteoblasts
which continues throughout life.

What is the role of mesenchymal stem cells, their niche and
extracellular matrix in bone regeneration?
• Fibrous and non-fibrous elements of the extracellular matrix provide a number
of critical functions central to tissue regeneration and include
1. A reservoir of growth and differentiation factors that can be released in well-
controlled spatial and temporal sequences
2. Induction of angiogenesis
3. Homing signals for mesenchymal stem cells
4. Bioactive space maintaining matrix for cell differentiation
5. An environment of both osteoinduction and osteoconduction

• Growth factors are soluble signalling proteins that induce specific biological
responses, including cell survival, migration, proliferation and differentiation.
• The concepts behind the use of growth factors and differentiation factors in
oral tissue regeneration are based on the seminal research by Marshall R. Urist
in the late 1960s .
• In the late 1980s to early 1990s the use of growth factors started to be tested
directly for periodontal regeneration.
• Growth factors can be delivered directly at the specific site or be loaded on
scaffolds, alone or in combination with other molecules in form of cocktails,
allowing their release in a controlled manner.

• The growth factors tested, so far, for periodontal regeneration are the following
ones:
Growth and differentiation
factors
Mediators of bone
metabolism
• Platelet derived growth factor
(PDGF)
• Insulin derived growth
factor(IDGF)
• Fibroblast growth factor(FGF)
• Vascular endothelial growth
factor (VEGF)
• Transforming growth factor
(TGF)
• Growth factors in platelet
concentrates concentrates
• Bone morphogenetic proteins
(BMP’s)
• Growth differentiation factor 5
(GDF-5)
• Attachment factors (Fibronectin)
• Extra cellular matrix proteins (
Enamel matrix proteins)

Biologic agents used in periodontal regeneration

Effects of growth factors used for periodontal tissue engineering

Recombinant Human Platelet-Derived Growth Factor-BB
(rhPDGF-BB)
Rationale
• PDGF-BB is involved in wound healing stimulating the potential for
regeneration of the periodontal tissues.
• Three different forms of PDGF are known: PDGF-AA, PDGF-AB, and PDGF-
BB.
• After hard or soft tissue injury, PDGF is released by blood platelets binding to
specific cell surface receptors.
• GEM 21S, (Osteohealth, Boston, MA) uses 𝛽-tricalcium phosphate (𝛽-TCP) as a
carrier of a highly purified rhPDGF-BB, providing physical structural support
and space maintenance.

•Recombinant human platelet-derived growth factor (rh-PDGF) can be used to treat
intrabony defects and gingival recession deformities.
•It is manufactured using recombinant DNA technology, and it is mitogenic and chemotactic
for osteoblasts, cementoblasts, and PDL cells.
•Its clinical use in conjunction with a carrier (-TCP or DFDBA) has been investigated with
clinically positive results.

The Effect of Rhpdgf-Bb on Patients with Osseous Defect: When the studies were
pooled for meta-analysis, the bone fill % (BF%) of patients in the treatment groups, all of
whom had received 0.3 mg/ml rhPDGF-BB, was 22.71% higher than that of patients in the
control groups (MD = 22.71, 95%CI = 7.78~37.65, p = 0.003).
Meta-analysis of linear bone growth (LBG) outcomes also showed significant differences
in the predicted direction between treatment and control groups (MD = 1.00, 95%CI =
0.32~1.69, p = 0.004).
The Effect of Rhpdgf-Bb on Patients with Gingival Recession: The use of 0.3 mg/ml
rhPDGF-BB produced no statistically significant effect on GR among patients suffering
from periodontal osseous defect.
(Feifei Li et al. , 2017)

Fibroblast growth factor-2 (FGF-2)
• FGF-2 accelerates the proliferation of fibroblastic cells, enhances the angiogenesis, and
increases the expression of BMP-2 and osteoblast differentiation markers, thus
promoting bone deposition.
• FGF-2 enhances the proliferative responses of PDL cells, while inhibiting their
mineralizing activity and the induction of alkaline phosphatase.
• The suppression of cytodifferentiation of PDL cells into mineralized tissue-forming cells
by means of FGF-2 might lead to an acceleration of periodontal regeneration.

Reconstructive periodontal surgery (part1+2+3)

Reconstructive periodontal surgery (part1+2+3)

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