PERIODONTAL - SURGERY

2. GUIDED TISSUE REGENERATION
GUIDED TISSUE
REGENERATION

3. CONTENTS
• Introduction
• History
• The Biologic Concept
• Melcher’s Concept
• Indications
• Contraindications
• Design Criteria for GTR devices
• Objectives of ideal barrier membrane
• Classification
• Advantages and disadvantages of non resorbable
membrane
• Advantages and disadvantages of resorbable membrane

4. • Factors affecting outcome of GTR
• Surgical techniques and approach
• Healing of GTR treated bone defects
• Guided bone regeneration
• Post operative considerations
• Types of complications possible
• Evaluation of GTR treatment outcome
• Current status
• Addition of antimicrobial substances.
• Microbiota of failing GTR
• Conclusion
• References.

5. INTRODUCTION
o In recent times, the use of regenerative procedures aimed at restoring the
lost periodontal support has become more common. Indication of
applying regenerative periodontal therapy is often based on esthetic
considerations besides the fact that function or long term prognosis of the
involved teeth may be improved.
o Periodontal 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.(Glossary of
periodontal term 1992)
o GTR procedures were developed to accomplish the objectives of epithelial
exclusion via controlled cell/tissue repopulation of the periodontal wound,
space maintenance and clot stabilization.

6. What is GTR?
• The 1996 World Workshop in Periodontics defined GTR
as “procedures attempting to regenerate lost
periodontal structures through differential tissue
responses’’.
• The AAP has defined GTR as “the procedure by which a
barrier is utilized to exclude epithelium from the root
surfaces”.
• Procedures attempting to regenerate lost periodontal
structures through differential tissue responses. (GPT
2001).

7. o Barriers are employed in the hope of excluding
epithelium and connective tissue from the root surface in
the belief that they interfere with regeneration.
o This method is derived from the classic studies of
Nyman(1982), Lindhe(1984), Karring(1986) and
Gottlow(1986) and is based on the assumption that only
the PDL cells have the potential for regeneration of the
attachment apparatus of the tooth.

8. HISTORY
• In 1976 – Melcher described the basic concept that led
to development of GTR.
• In 1982 – Nyman et al first described the clinical
procedure of GTR using a non absorbable barrier,used
in periodontal surgery which allowed regeneration of
cementum, periodontal ligament and alveolar bone was
a cellulose acetate (paper) laboratory filter (Millipore
filter).
• In 1982 – W.L. Gore and associates, began
investigating materials that would limit the migration
of epithelial around dental implants and teeth.

9. • In 1982 – ePTFE was introduced.
• 1982 era - “Era of tissue integration”
• 1983, era was called “Era of cell separation”
• 1985 - Era of clinically manageable membrane development.
• Gotlow et al. 1986 coined the term Guided Tissue Regeneration and it is also referred
to as selective cell repopulation or controlled tissue regeneration.
• 1988 -> the space making property was developed.
the central portion of the membrane was stiffened to support the membrane and resist
collapse from the pressure of overlying tissue, while periphery was porous and soft.

10. THE BIOLOGIC
CONCEPT/FOUNDATION OF GTR
oPrinciple of GTR is based on the assumption that only the
periodontal ligament cells have the potential for the regeneration
of the attachment apparatus of tooth.
o It consists of placing barriers of different types to cover the
bone and periodontal ligament thus temporarily separating them
from gingival epithelium.
oExcluding the epithelium and the gingival connective tissue
from the root surface during the post surgical healing phase -
Prevents epithelial migration into the wound.
Favours repopulation of the area by cells from the periodontal
ligament and bone cells.
oGuided tissue regeneration with the use of barrier membranes
works on the principle of cell exclusion.

11. MELCHER’S CONCEPT/TISSUE
COMPARTMENT HYPOTHESIS
Melcher’s hypothesis
In 1976, Melcher suggested in a review paper that the type of
cell which repopulates the root surface after periodontal
surgery determines the nature of the attachment that will
form.
Root surfaces may be repopulated by four different types of
cells:
1. Epithelial cells.
2. Cells derived from the gingival connective tissue
3. Cells derived from the bone
4. Cells derived from the periodontal ligament

12. Figure: Schematic diagram depicting the concept of Melchers
hypothesis

13. INDICATIONS
2 to 3 walled intrabony defects.
Class II furcation defects.
Recession defects.
Circumferential defects
Alveolar ridge augmentation.
Repair of apicoectomy defect.
Osseous fill around immediate implant placement
sites.
Repair of osseous defect associated with failing
implants.
Thick gingival biotype.

14. CONTRAINDICATIONS
o Infection at the site of defect
o Poor oral hygiene
o Smoking
o Tooth Mobility
o Defect < 4mm
o Width of attached gingiva at defect site ≤1 mm
o Thickness of attached gingiva at defect site ≤0.5mm
o Furcation with short root trunks
o Advanced lesions with little remaining support
o Horizontal bone loss
o Multiple defects
o Any medical condition contraindicating surgery

15. DESIGN CRITERIA FOR GTR
DEVICES
Scantlebury, Gottlow and Hardwilk (1982)
• Biocompatibility
• Cell exclusion
• Space maintenance
• Tissue integrity
• Ease of use
• Biological activity
Greenstein & Caton (1993):
• Biocompatibility
• Cell occlusiveness
• Spacemaking
• Tissue integration
• clinical manageablilty

16. OBJECTIVES OF AN IDEAL
BARRIER MEMBRANE
• It should fulfill occlusive requirements of GTR concept.
• It should be biocompatible and/or allow tissue integration.
• Non-toxic and non-carcinogenic.
• Chemically inert and non-antigenic.
• Easily sterilizable.
• Easy to handle during surgery.
• Sufficiently rigid so as to maintain space between it and root
surface.
• Supplied in different designs to suit the specific clinical situations
• Easily storable and long shelf life.
• Easily retrievable in case of complication.
• Should not be too expensive.
• able in case of complication.

17. CLASSIFICATION
Classification by Minabe in 1991:
Nonabsorbable
-Polytetrafluoroethylene (e-PTFE) type
-Titanium reinforced polytetrafluoroethylene type
-Rubberdam
Bioabsorbable
Natural
-Collagen type
-Synthetic polymer type(lactate-glycol
compound)
-Connective tissue graft
-Durameter
-Oxidized cellulose
Synthetic
-Alloderm
-Polyurethanes
-Polylactic acid
-Polyglycolic acid

18. Classification by Gottlow in 1993:
Millipore Filter
Expanded polytetrafluoroethylene membrane (e-
PTFE) GORE-TEX
Nucleopore membrane.
Rubber Dam.
Ethyl cellulose.
Semi-permeable silicon barrier.
Collagen – Biomend, Periogen, Paroguide, Biostite,
Tissue guide.
Polylactic acid Membrane – Guidor, Vicryl, Atrisorb,
Resolut, Epiguide, Biofix.
Vicryl Mesh.
Cargile Membrane.
Oxidised Cellulose Membrane.
First generation membranes: Non-resorbable membranes
Second generation membrane: Resorbable membranes

19. Third generation membrane:
They are the resorbable membrane with added
growth factor incorporated with an aim of
improving early bone healing.

20. Advantages and disadvantages
of non-resorbable membranes
Advantages:
Excision of epithelial and gingival CT
from PD defect
Maintains space between defect and barrier
allowing entry of cells from PDL and alv bone.
Helps to stabilize clot which may enhance
regeneration
Space maintainence over an extended time and
can remain in place for longer period.
Disadvantages:
Membrane
exposure
Contamination
Infection
Bone loss

21. Advantages and disadvantages of
resorbable membranes
Advantages
Reduce operatory time
More tissue compatibility
Increase patient acceptance
Elimination of second surgery for
barrier removal
Reduces risk of loss of regenerated
attachment owing to reentry surgery.
Disadvantages
Resorbable
High Cost
Instability of barrier
Biodegradation rate cannot
be controlled
Lack of stiffness-collapse of
membrane.

23. Resorbable versus non-resorbable
membranes
• AAP paper on regeneration 2005, stated that
“there is no difference between resorbable and
non-resorbable membranes and that evaluation of
both polyactic acid and collagen membranes have
reported clinical improvements similar to those
achieved with non-resorbable membranes.”

24. Lindhe (2003), in a review of 21 clinical trials (423
mandibular grade II furcations), concluded:
• There was no significant difference between
bioabsorbable and nonabsorbable membranes.
• GTR significantly improved the horizontal CAL
results over OFD: 2.5mm versus 1.3mm.
• Complete closure was variable (0-67%).
• GTR significantly improved vertical attachment
and a reduction in PD.
• CAL-H in maxillary furcation was only 1.6mm,
and the results were variable.

25. • Parrish et al in 2009 had systematically reviewed on
non bioabsorbable versus bioabsorbable membrane
assessment of their clinical efficiency in GTR
technique and concluded that GTR was confirmed to
be superior to OFD.

26. FACTORS AFFECTING THE
OUTCOMES OF GTR
Barrier independent factors
• Patient factors
• Defect factors
• Surgical technique

27. Patient factors

28. Defect factors
 Type of defect:- Intrabony defects or class II furcations.
 Morphology of defect:- Deeper defect shows more gain
in CAL as compared to wider defects which show less
gain in CAL (Garrett et al 88; Tonetti et al 93,96).
 Defects deeper than 3 mm - greater probing attachment
gains than defects of 3 mm or less (Cortellini P 1998).

29. • Root canal treatment (Cortellini & Tonetti 2000)
• Tooth mobility with < 1mm horizontally have been
positively related to PDL regeneration.(Cortellini et al
2001; Trejo & Weltman 2004)
• Gingival thickness <1mm exhibited more post operative
recession(Anderegg et al 95) and severity of flap
dehiscence. (Anderegg et al 91)
• Number of residual bony walls was related to the
outcomes of various regenerative approaches
(Goldman & Cohen 1958, Schallhorn et al. 1970).

30. Surgical technique
– Improper incision placement.
– Traumatic flap elevation.
– Excessive surgical time.
– Inadequate closure or suturing.
– Bacterial contamination: Colonization may occur on
the coronal part of membrane.
• Administration of systemic antibiotics has shown no improvement
after GTR therapy (Slots 94) as they are ineffective in prevention of
plaque biofilm. (Frandsen et al 94)

31. Barrier dependent factors
• Inadequate root barrier adaptation.
• Non-sterile technique
• Instability of barrier against root.
• Premature exposure of barrier to oral
environment and microbes.
• Premature loss or degradation of barrier.

32. The primary factors affecting the clinical outcomes of
periodontal surgery have been classified by
Kornman and Robertson (2000) as:
• 1) Bacterial contamination
• 2) Innate wound-healing potential
• 3) Local site characteristics and
• 4) Surgical procedure

33. Cortelini and Tonetti in 2000 gave the
following factors:

34. PASS principle
Hom-LayWang and Boyapati in 2006 have
suggested 4 factors that play a critical role in
regeneration -
• P- Primary wound coverage (passive flap tension)
• A- Angiogenesis
• S- Space maintenance
• S- Stability

35. SURGICAL TECHNIQUE AND
APPROACHES.
Conventional approach
• access flap or modified Widman flap
• Full-thickness flaps are elevated to try to preserve the
marginal and interdental tissues to the maximum possible
extent.
• Vertical releasing incisions
• Coronal displacement of the flap
• In 1995 and 1999, Cortillini and Tonetti have described flap
techniques for the preservation of the interdental papillae.
These techniques i.e. the modified papilla preservation flap
and the simplified papilla preservation flap can be used with
better prognosis while attempting GTR procedure.

36. Modified papilla preservation technique
The rationale for developing this technique was
to achieve and maintain primary closure of
the flap in the interdental space over the
membrane.

37. Interdental tissue maintenance
• Interproximal tissue maintenance is a technique
proposed by Murphy to be used in combination with
nonresorbable barrier membranes and grafting
material.
Free gingival graft at membrane removal
• The use of free gingival grafts has been proposed to
afford better coverage and protection of the
regenerated interproximal tissues after membranes
removal when the occurrence of a dehiscence of the
gingival flap does not allow a primary coverage of
the interdental area .

38. • In a randomized controlled clinical study of 45 patients
significantly greater amounts of probing attachment were
gained with the modified papilla preservation technique,
in comparison with either conventional guided tissue
regeneration or access flap surgery
• The sites accessed with the modified papilla preservation
technique showed primary closure of the flap in 73% of
the cases. (Cortellini et 1995)

39. • Thorough pre-surgical preparation of the patient consisting of SRP, oral
hygiene instructions and oral hygiene maintenance monitoring must be
done.
• Raise a muco-periosteal flap with crevicular and vertical incisions,
extending a minimum of 2 teeth mesially and 1 tooth distally to the tooth
being treated.
• Debride the osseous defect and thoroughly plane the roots.
• Trim the membrane with sharp scissors to the approximate size of the area
being treated.
• The apical border of the material should extend 3-4mm apical to the
margin of the defect and laterally 2-3mm beyond the defect.
• The occlusal border of the membrane should be placed 2mm apical to the
CEJ.

40. • Suture the membrane tightly around the tooth with a sling
suture.
• Suture the flap back in its original position or slightly
coronal to it, using independent sutures interdentally and
in the vertical incisions.
• The flap should cover the membrane completely.
• Periodontal dressing is optional.
• Antibiotic therapy given for a week.

41. • After 4-6 weeks, the margin of the membrane becomes exposed.
• The membrane is removed with a gentle tug.
• If it cannot be removed easily, the tissues are anaesthetised and the
material is removed surgically using a miniflap.
• The results obtained with the GTR technique are enhanced when the
technique is combined with bone grafts placed in the defects.
• The area should be scaled every 3 months for about 9 months.
• By the 9th month, there should be radiographic evidence of bone
formation.
• Second surgery is not needed with resorbable membranes.

42. HEALING OF GTR TREATED BONE
DEFECTS
• Following initial organization of the blood clot,
protected by the membrane, regeneration was
initiated by deposition of woven bone along new
vascular structures originating from the bony walls
• The primary spongiosa was characterized by blood
vessels originating from marrow spaces.

43. • The network of woven bone was reinforced by
concentrically deposited parallel-fibered lamellar bone,
which resulted in the development of a new cortical
structure at the periphery of the defects
• The onset of bone remodeling with the formation of
secondary osteons could be observed in the newly
formed bone close to the defect margins
• The duration of the maturation process exceeded 4
months in the large defects .
(Schenk et al 1994)

44. GUIDED BONE REGENERATION
• In GBR, the osseous defects are covered with a barrier membrane, which is
adapted closely to the surrounding bone surface
• Nonosseous cells (epithelial cells and fibroblasts) are inhibited and space
is preserved between the bone surface and membrane.
• Osteoblasts derived from the periosteum and bone are selectively induced
on the osseous defect area, facilitating new bone formation
• GBR is for the regeneration of supporting bone.
• Because of less membrane exposure, the chance of infection is decreased
making bone regeneration highly predictable.

45. GBR – The Principle
• The GBR biological rationale advocated the mechanical
exclusion of undesirable soft tissues for growing into the
osseous defect, thereby allowing only osteogenic cell
populations derived from the parent bone to repopulate the
osseous wound space (Dahlin et al. 1988; Hammerle et al.
1995).

47. POSTOPERATIVE CONSIDERATIONS
• CHX mouthwash should be used for 10 days.
• If the material becomes exposed, CHX should be used until removal.
• Tetracycline 250 mg daily or doxycycline 100 mg twice daily should be used for 7 to 10 days.
• Periodontal dressing may or may not be used depending on the clinician.
• Gentle brushing is recommended for the first 6 weeks.
• Flossing at the treated site is to be avoided while the material is in place.
• The patient should be seen biweekly if there is no membrane exposure and weekly if exposure is
present.
• Do not attempt to cover previously exposed material.
• The material should be removed immediately if any complication develop.
• Avoid deep mechanical instrumentation and probing of the site for 6 to 9 months.

48. TYPES OF COMPLICATIONS POSSIBLE
• Membrane exposure - the most common complication with prevalence 70-
80% (Murphy 1995) &
50% -80% (Becker et al 1988, Cortellini et al 1993).
• Prevalence of membrane exposure has been highly reduced with the use of
access flaps (MPPT, SPPT, interproximal tissue maintenance)
• Other complications
 Pain
 Swelling
 Abscess formation
 Apical perforation of the flap.
 Purulence
 Sloughing
 Perforation
 Bacterial contamination
 Root resorption and ankylosis

49. Evidence based
Non-resorbable membranes:
• ePTFE membrane plus DFDBA versus allograft alone in
intrabony defects - no significant differences between
groups.
• ePTFE membranes in mandibular Class II furcation defects
- significant clinical improvement. However, only one study
reported complete clinical closures (Pontoriero et al 1988).
• furcation defects with a combination of GTR barriers and
bone grafts appears to produce greater clinical
improvements than GTR alone (Evans et al 1996).

50. Bioabsorbable Membranes:
• Evaluations of both PLA and collagen membranes have
reported clinical improvements similar to those
achieved with nonresorbable membranes.
• Addition of bone grafts with collagen membranes
appears to improve the clinical results in furcation, but
not intrabony, defects.
• PLA, PGA or combination of PLA and PGA -
comparable clinical results to ePTFE.
• PLA/PGA copolymer to a type I collagen membrane in
the treatment of intrabony defects has reported similar
clinical improvements.

51. Furcation defects:
• Most favorable results - Class II mandibular furcations.
• Less favorable results - mandibular and maxillary Class III defects
and maxillary Class II defects.
• Pontoriero et al. 1987 - showed complete defect closure in 67% of
Class II defects and 25% of Class III defects in the group receiving
ePTFE membrane.
• Most favorable results - combination of GTR and bone grafts.
• ePTFE+bone graft – significant results
• Polymeric or cellulose barrier + bone grafts - no difference
• Mandibular and maxillary buccal Class II furcation defects.

52.  A systematic review of GTR for periodontal furcation
defects by Jepsen in 2002 -GTR was consistently more
effective than OFD in reducing open horizontal
furcation depths, horizontal and vertical attachment
levels and pocket depths for mandibular or maxillary
class II furcation defects.
 In another systematic review by Gunsolley et al, the
treatment of furcation defects, GTR procedures
compared to OFD controls result in significantly more
favourable gains in VPAL, reductions in VPD and
improvements in HOPA measurements.

53. Evidence of application of GTR in
Intrabony defects
• Nickles et al 2009 evaluated 10-year results after open flap
debridement (OFD) and guided tissue regeneration (GTR) therapy of
infrabony defects in a randomized controlled clinical trial and
concluded that ten years after OFD and GTR in infrabony defects 35 of
41 teeth were still in place. The study failed to show statistically
significant attachment gain differences between both groups after 120
months.
• Nygaard-ostby et al 2010 in a 10-year randomized-controlled trial
evaluated the stability of treatment outcomes following the implantation
of autogenous bone graft with or without guided tissue regeneration
(GTR) in the treatment of deep intra-bony periodontal defects. The
authors concluded that statistically significant differences were found
with the adjunct use of GTR to an autogenous bone graft at 10 years.

54. • Stavropoulos and Karring in 2010 presented the 6-year results of a
randomized-controlled clinical trial evaluating GTR combined with or
without deproteinized bovine bone mineral (DBBM) (Bio-oss) in
intrabony defects. Statistically significant clinical improvements were
observed and these improvements can be preserved on a long term
basis.
• Two meta-analyses by Laurell et al in 1998 and Cortilinni et al in
2000 have reported greater benefits to GTR than found in the present
systematic review. These reviews indicated a difference in attachment
gain between GTR and OFD of 2.7mm and 1.6mm difference
respectively.
• In a systematic review by Needleman et al in 2002, results indicated
that for attachment change, the mean difference between GTR and
OFD was 1.11mm. Overall, GTR was more effective than OFD in
improving attachment levels.

55.  In another systematic review by Gunsolley et al, the
conclusions drawn were:
• In the treatment of intrabony defects, GTR procedures
compared to OFD controls result in significantly more
favourable gains in CAL and PD.
• Meta-analysis did not show any significant superior results
among the barrier types evaluated.
• The use of specialized flap techniques may enhance the
clinical outcomes, but insufficient data is present.
 In a chocrane based review by Needleman et al published
in 2005 it was concluded that 11 out of 16 studies showed
greater attachment gain for GTR than for OFD. There is
little benefit of a combination therapy of bone grafts + GTR
over GTR alone. Choice of flap may be important.

56. Evidence of application of GTR in
recession defects
• Pini prato et al 1992 – First described in a comparative clinical study GTR
vs mucogingival technique.
• Zucchelli et al 1998 – conducted a mucogingival and GTR study and
concluded that the mucogingival bilaminar technique is at least as effective
as GTR procedures in the treatment of gingival recessions and recession
depth is not the parameter which influences the selection of the surgical
procedure.
• Wang et al 2001 compared GTR and sub epithelial connective tissue graft
– no difference in improvements was found between both the groups.
• Chambrone et al 2010 – With respect to gingival recession and keratinized
tissue changes, there was a statistically significantly greater reduction in
gingival recession and greater gain in the width of keratinized tissue for
subepithelial connective tissue grafts compared to GTR bioabsorbable
membrane sites. Concluded that GTR may be used as root-coverage
procedures for the treatment of recession-type defects but better results are
seen with the use of SECTG.

57. • Danesh-Meyer et al (2001) had reviewed the value of GTR in the
management of gingival recession defects. The authors concluded that GTR
does not appear to offer a significant advantage over mucogingival
procedures. They recognized difficulties associated with GTR including
primary wound closure, secondary membrane exposure, space maintenance
and unacceptable foreign body reaction.
• Al Hamdan et al 2003 had done a meta analysis to determine whether
guided tissue regeneration based root coverage (GTRC) provides
significantly improved clinical outcomes compared to conventional
periodontal plastic surgical approaches for the treatment of marginal tissue
recession. The meta analysis concluded that guided tissue regeneration
based root coverage can be used successfully to repair gingival recession
defects.

58. Combination therapy
• Karring and Cortellini 1999 indicated that an added benefit may be
obtained by the use of grafting materials in combination with barrier
membranes.
• Murphy and Gunsolley 2003 examined the effect of the addition of an
augmentation material under the physical barrier. Collectively reviewing
all barriers - vertical probing attachment level was significantly enhanced
by the addition of a particulate bone graft.
• Blumenthal et al in 1990 researched 15 test and 15 control defects with
one-year reentry showed a significant improvement in collagen barrier plus
DFDBA vs collagen barrier-alone treated sites. Defect fill was 63% versus
31% in favor of the collagen- and DFDBA treated sites.
• Chen et al (1995) in their study performed to evaluate the addition of bone
grafts with or without collagen membranes to treat intrabony defects
concluded that utilizing 6 to 12 month reentry of eight test and eight control
defects showed no difference in CAL gain or defect fill between the test and
control groups.

59. WWP and AAP in 2005 papers on periodontal regeneration in
intrabony defects and furcations found the following:
• GTR provided additional benefits over OFD in CAL and PDR in
intrabony defects and furcations.
• Bone replacement grafts enhance GTR treatment outcomes in
furcations and not in intrabony defects.
• Bioabsorbable and nonabsorbable membranes provide similar
outcomes in intrabony defects and CAL-H levels in furcations.
• Only e-ptfe membranes significantly enhanced the vertical probing
attachment level in furcations.
• Acc to the participants of the workshop… GTR should be limited to
mandibular and maxillary buccal grade II furcation defects.

60. Evaluation of GTR treatment outcome
Clinical methods–
 Probing- soft tissue changes (bleeding on
probing)
pocket depth
clinical attachment level
 Bone levels- re-entry procedures
bone sounding
Radiographic bone changes
Histological methods
Re-entry surgery

61. CURRENT STATUS/RECENT
ADVANCES IN GTR
• Inion GTR membrane - biomedical material of the third
generation which combines biodegradability with bioactivity.
• Tetracyclines (Chung et al 1997).
• Membranes containing metronidazole
• Incorporation of CHX into GTR membranes (Chen et al. 2003)
• Combination of growth and differentiation factors like
PDGF,emdogain and BMPS.

62. ADDITION OF ANTI MICROBIAL
SUBSTANCES
• Controlling bacterial colonization in the early healing phase and
reducing the spread of infection. The addition of antimicrobial
substances increase predictability.
• Hung et al (2005) - incorporation of amoxicillin or tetracycline into
various GTR membranes may enhance the attachment of periodontal
ligament cells in the presence of the oral pathogens S mutans and Aac.
• Cheng et al (2009) - penetration of S mutans and Aac through
amoxicillin- or tetracycline loaded ePTFE, glycolide fiber and collagen
membrane was delayed and/or reduced.
• Bottino et al (2011) proposed a novel Functionally graded membrane
(FGM) designed and fabricated via sequential multilayer
electrospinning. Consists of a core layer and two functional surface
layers interfacing with bone (n-HA) and epithelial tissues.
Incorporation of n-HA to enhance osteoconductive behavior and
metronidazole to combat periodontal pathogens.

63. MICROBIOTA OF FAILING GTR
• Mombelli et al 1997 gram- negative anerobic rods
made up 31% of total membrane isolates at 6 weeks
post surgery .
• One site yielded high proportions of P.gingivalis, 6
sites demonstrated Prevotella intermedia and 6 sites
showed Prevotella melaninogenica.
• Fusobacterium and Capnocytophaga species were
also frequent membrane isolates.

64. • Nowzari & Slots 1995 detected P.gingivalis in 3
periodontal sites that experienced a net loss of clinical
attachment after membrane removal.
• A.actinomycetemcomitans was recovered from a
periodontal sites that gained as little as 1mm of probing
attachment.
• Total microbial counts and percentage of
Peptostreptococcus micros, Capnocytophaga species
and motile rods on barrier membranes seemed also
negatively to affect periodontal regeneration.

65. CONCLUSION
• The principle of GTR lies in the establishment of the cells of
periodontal ligament to selectively repopulated the root surface.
• Clot establishment and stabilization, site selection, epithelial cell
exclusion, space provision, neovascularization, and complete gingival
coverage are favourable characteristics in any GTR procedure.
• The use of GTR membranes can lead to significant periodontal
regeneration and formation of cementum with inserting fibers, although
complete regeneration has never been reported.
• It has considerable value as a regenerative procedure, particularly in
intrabony, furcation and gingival recession defects.
• In the future, GTR can be combined with the use of biological growth
factors that allowed for selectively control the type of cells proliferated
from the fibroblast precursor.

66. REFERENCES
• Carranza’s Clinical Periodontology, 10th edition.
• Clinical perioodntology & oral implantology- Lindhe 5th edition.
• Clinical periodontology & oral implantology- Lindhe 4th edition.
• Atlas of cosmetic and reconstructive periodontal surgery- Edward
Cohen. 3rd edition.
• Becker et al. Clinical applications of guided tissue regeneration:
surgical considerations. Periodontology 2000, vol 1.
• Murphy KG, Gunsolley JC. Guided tissue regeneration for the
tretment of periodontal intrabony and furcation defects. A systematic
review. Ann periodontol 2003; 8: 266-302.
• Jepsen S, Eberhard J, Herrera D, Needleman I: A systematic review
of guided tissue regeneration for periodontal furcation defects. What
is the effect of guided tissue regeneration compared with surgical
debridement in the treatment of furcation defects? J Clin
Periodontol 2002; 29(Suppl. 3): 103–116.
• Needleman I, Tucker R, Giedrys-Leeper E, Worthington H. Guided
tissue regeneration for periodontal intrabony defects – a Cochrane
Systematic Review. Periodontol 2000 2005; 37: 106-103.

67. • Paolantonio M, D'Archivio D, Placido GD,Tumini V, Di Peppe G,
Matarazzo ADG, De Luca M. Expanded poly tetrafluoroethylene and
dental rubber dam barrier membranes in the treatment of
periodontal intrabony defects. A comparative clinical trial. J Clin
Periodontol 1998:25: 920-928.
• Gottlow J, Nyman S, Lindhe J, Karring T, Wennstrom J. New
attachment formation in the human periodontium by guided tissue
regeneration. on. J Clin Periodontol 1986: 13: 604-616.
• Gottlow J, Nyman S, Lindhe J, Karring T, Wennstrom J. New
attachment formation in the human periodontium by guided tissue
regeneration. on. J Clin Periodontol 1986: 13: 604-616.
• Danesh Meyer MJ, Wikesjo UME. Gingival recession defects and
guided tissue regeneration: a review. J Periodont Res 2001; 36: 341-
354.
• Bunyaratavej P, Wang HL. Collagen membranes: A review. J
Periodontol 2001; 72: 215-220.