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Periodontal regeneration


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Periodontal regeneration, techniques, materials, future trends

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Periodontal regeneration

  1. 1. Periodontal Regeneration PRESENTED BY: PRABLEEN ARORA MDS STUDENT
  2. 2. TERMINOLOGY ( glossary of periodontal terms) A graft is any tissue or organ used for implantation or transplantation. An autograft is a tissue transferred from one position to a new position in the same individual. Homograft: a graft between genetically similar individuals of the same species. Isograft: graft between genetically identical individuals, identical twins.
  3. 3. Allograft. A tissue (bone) graft between individuals of the same species but of nonidentical genetic disposition, an allograft was formerly referred to as a homograft. Xenograft is a tissue graft between members of different species. Alloplast. A synthetic bone graft material: a bone graft substitute. Attachment apparatus. The cementum, the periodontal ligament and the alveolar bone.
  4. 4. Bone fill. The presence of bone tissue within a periodontal osseous defect following therapy. Repair: describes healing of a wound in response to injury in an attempt to restore normal structure and function. Regeneration. refers to the reproduction or reconstitution of a lost or injured tissues that the architecture and function of the lost or injured tissues are completely restored.. Periodontal regeneration is defined as the restoration of lost periodontium or supporting tissues and includes formation of new alveolar bone, new cementum, and new periodontal ligament.
  5. 5. • Re-attachment- was used to describe the regeneration of a fibrous attachment to a root surface surgically or mechanically deprived of its periodontal ligament tissue. Whereas • New attachment was preferred in the situation where the fibrous attachment was restored on a root surface deprived of its connective tissue attachment due to the progression of periodontitis. • Guided tissue regeneration is a method for the prevention of epithelial migration along the cemental wall of the pocket and maintaining space for clot stabilization.
  6. 6. BIOLOGY OF PERIODONTAL REGENERATION POSSIBLE OUTCOMES OF A PERIODONTAL THERAPY:  New attachment with periodontal regeneration is the ideal outcome of therapy because it results in obliteration of the pocket and reconstruction of the periodontium . However, the techniques available are not totally dependable, and other therapeutic results may be seen as follows:  Healing with a long junctional epithelium, which can result even if filling of bone has occurred.  Ankylosis of bone and tooth with resultant root resorption.  Recession.  Recurrence of the pocket.  Any combination of these results.
  7. 7. • In 1976, Melcher in a review paper suggested that the type of cell which repopulates the root surface after periodontal surgery determines the nature of the attachment that will form. • After flap surgery the curetted root surface may be repopulated by four different types of cell : • 1. Epithelial cells • 2. Cells derived from the gingival connective tissue • 3. Cells derived from the bone • 4. Cells derived from the periodontal ligament.
  8. 8. PERIODONTAL WOUND HEALING If the epithelium proliferates along the root surface before other tissues reach the area, the result will be long junctional epithelium. If the cells from gingival connective tissue are first to populate the area, result will be fibers parallel to the tooth surface & remodelling of alveolar bone with no attachment to the cementum. If bone cells arrive first, root resorption & ankylosis may occur. When cells from the periodontal ligament proliferate coronally, there is new formation of cementum & periodontal ligament.
  9. 9. OBJECTIVES OF REGENERATIVE THERAPY – Pocket reduction; – Clinical attachment gain; – Bone fill of the osseous defect; and – Regeneration of new cementum, PDL, and bone as determined by histologic analysis. – Establishment of healthy maintainable environment.
  10. 10. INDICATIONS OF REGENERATIVE THERAPY Deep Intraosseous Defects – The deeper the defect , the greater amount of bone fill that can be expected. – Greater the number of osseous walls and the greater the support and containment for the graft material, the greater will be the bone fill. Tooth Retention The use of bone grafts may restore functional stability to such a degree as to obviate the need for extraction. Support for Critical Teeth – Teeth severely weakened by loss of alveolar support can benefit from the use of osseous grafts. – This may be the case for an abutment tooth or those teeth that are critical for the preservation of arch integrity.
  11. 11. Bone Defects Associated With Aggressive Periodontitis These extensive lesions have been reported to respond very favourably to osseous grafting, especially when grafting is combined with an antibiotic, such as tetracycline. Esthetics • The use of osseous grafts to reconstruct bone architecture allows placement of the gingival margin as close as possible to its original position. Successful healing will result in minimal apical displacement of the gingival margin. Furcation Defects – This indication applies mainly to class II furcation defects. – Bone grafts, especially if used in conjunction with guided tissue regeneration, have proven to be the therapeutic modality of choice for treating this type of lesion.
  12. 12. ASSESSMENT OF PERIODONTAL REGENERATION • Evidences of reconstruction of the marginal periodontium can be obtained by • Clinical, • Radiographic, • Surgical re-entry or • Histologic procedures. • All of these methods have advantages and shortcomings.
  13. 13. Clinical methods • Consists of comparison of pre and post treatment pocket probing and determination of clinical gingival findings. • Determination of attachment level is more useful than probing depth. • Depth of the probe penetration in a periodontal pocket varies according to the • degree of the inflammatory changes at the base of the pocket. • Probing force
  14. 14. • Therefore even though the forces used may be standardized with the pressure sensitive probes, there is inherent margin of error in this method that is difficult to overcome. Fowler and colleagues (1982) have calculated this error to be 1.2mm. • Therefore, clinical methods are subjected to errors. • This reproducibility of probing may be facilitated in part by using a grooved stent to guide the introduction of the probe
  15. 15. Radiographic Methods:  To detect changes in bone support over time, two or more radiographs must be compared.  Radiographic evaluation of periodontal regeneration allows assessment of the bone tissue adjacent to the tooth.  Standardized technique for reproducible positioning of the film and tube is required.  The simplest methods for assessment of alveolar bone involve direct measurements from the cemento-enamel junction to the alveolar bone levels on radiographs.
  16. 16. Surgical Re-entry • The surgical re-entry after a period of healing can give a good view of the state of the bone crest that can be compared with the view taken during the initial surgical intervention and can also be subject to measurements. • Models from the impression of the bone at the initial surgery and later at reentery can be used to assess the results of the therapy. • This method is very useful but has two shortcomings: • it requires a unnecessary second operation, and • it does not show the type of attachment that exists (i.e., new attachment or long junctional epithelium
  17. 17. Histologic Examination • Type of attachment can be detirmined only by histological analysis of the tissue blocks obtained from the healed site. • Ultimate standard to detect the presence of and to measure the extent of periodontal regeneration • For future histologic reference, notches can be placed clinically • (1) at the most apical part of the calculus • (2) real landmark that determines whether new attachment has taken place is the base of the pocket • (3) at the level of the osseous crest. Disadvantages of histological examination: The need to remove a tooth with its periodontium after successful treatment limits this method to volunteers who need the extraction for prosthetic or other reasons and agree to the procedure.
  18. 18. FACTORS AFFECTING THE OUTCOME OF PERIODONTAL REGENERATION • Attention has focused on some important • Patient and • Defect factors. PATIENT FACTOR Periodontal Infection • Periodontal regeneration does not treat periodontitis, but rather is an approach for regenerating defects that have developed as a result of periodontitis. – Therefore, appropriate periodontal treatment should always be completed before periodontal regeneration is initiated
  19. 19. • The persistence of • poor plaque control, • high levels of bleeding upon probing in the dentition, as well as the • persistence of high loads of total bacteria or of specific microbial pathogens (or complexes of pathogens) have all been associated in a dose-dependent manner with poor clinical outcomes. Diabetes Mellitus • Strongest potential influence on periodontal diseases. – In general, poorly controlled diabetes appears to be associated with an increased risk of loss of attachment and loss of bone. – Well-controlled diabetics do not appear to be at an increased risk for periodontitis.
  20. 20. Endodontic Status • Some have suggested that endodontically treated teeth may be less than ideal candidates for regenerative therapy. (Morris 1960). • Others have suggested little relationship between pulp status and regeneration. (Bjorn H et al. 1965) Tooth Mobility • Increased tooth mobility as a factor influencing the • severity, • rate of progression of periodontal disease, • effect of therapy as well as maintenance, has been examined in several studies.
  21. 21. • Fleszar et al. 1980, have reported a negative influence of increased baseline mobility. • They concluded that teeth with initially elevated tooth mobility gained less attachment than teeth with initial low mobility, regardless of the therapeutic modality rendered. Other patient factors • It has been suggested that other patient factors, genetics or stress levels, may be associated with sub-optimal regenerative outcomes. Age – There is no evidence to suggest that age effects the outcome following regenerative surgeries. – No differences have been demonstrated when patients ages 27 to 44 were compared to patients ages 48 to 66 in terms of outcomes following GTR surgery. (Machtel JP 1994)
  22. 22. Defect Factors Type of defect • Regenerative therapy is limited mainly to intrabony defects and class II furcations. Morphology of the defect • Defect morphology plays a major role in healing following periodontal regenerative treatment of intrabony defects. • Depth and width of the intrabony component of the defect influence the amount of clinical attachment and bone gained at 1 year.
  23. 23. The deeper the defect, the greater was the amount of clinical improvements, while the wider the defect, the lower were the attachment and bone gain. (Garrett et al. 1988; Tonetti et al.1996) DEEP DEFECT WIDE DEFECT
  24. 24. Defect Angle • Measured as the angle that the bony wall of the defect forms with the long axis of the tooth. • Cortellini and Tonetti (1999) demonstrated that defects with a radiographic angle of 25º or less gained consistently more attachment (1.6 mm on average) than defects of 37º or more. NARROW ANGLE WIDE ANGLE
  25. 25. – Hence, it may be stated that defect morphology expressed by a more acute angle of the defect (less than 45⁰) results in a substantially better treatment outcome than when the defect angle is greater. Walls • There is some evidence that 2 & 3wall infrabony defects respond better to regenerative therapy than 1-wall defects.
  26. 26. REQUIREMENTS FOR PREDICTABLE REGENERATION (1) Undisturbed Healing (2) Wound Stability (3) Space Provision (4) Root Biomodification (5) Thorough Root Planing (6) Preparation Of The Osseous Defects For New Attachment (7) Revascularization (8) Flap Management
  27. 27. BONE GRAFTING TECHNIQUE The following steps in the procedure provide a road map that leads toward success most the time. 1. Remove all etiologic factors. Local and systemic factors must be under control for grafts to be successful. 2. Stabilize teeth if necessary Extremely mobile teeth that are going to be treated may benefit from provisional stabilization for at least 6 months post surgically 3. Flap design with a plan for closure Scalloped incisions with full gingival preservation are necessary to be able to completely close the site 4. Degranulation of defect and flap All granulomatous soft tissues should be removed from the bony walls of the defect and the associated tooth surfaces. Inner aspect of the flap should be checked for tissue tags and epithelial remnants.
  28. 28. 5. Root preparation It is essential that all calculus, bacterial plaque, other soft debris and altered cementum be removed from the involved root surfaces 6. Pre-suturing Loose placement of sutures, left untied, prior to the filling of the defect reduces the possibility of displacing the graft material during the suturing process. 7. Condense graft materials well Small increments of material are placed in the defect, gently packed into the angles and base of the defect with small pluggers or curettes. Useful in this regard are sterile plastic or Teflon-lined amalgam carriers to place the material. 8. Fill to a realistic level. Defects should be filled with the synthetic graft materials only to the level of the defect walls. There is little suggestion that overfilling with these materials results in supracrestal bone formation. Overfilling may actually be counterproductive in that it may preclude proper flap closure, thereby retarding healing and possibly resulting in loss of the graft material.
  29. 29. 9. Periodontal dressing. The use of a firm, protective periodontal dressing for 10 days following bone replacement graft surgery is suggested. It has become popular not to use dressing for many periodontal surgical procedures. 10. Antibiotic coverage. They are administered in therapeutic doses for the first 10 days following surgery or until the patient can practice proper plaque control in the area. 11. Postsurgical care The patient is started immediately on gentle but thorough plaque- control methods, including the use of antibacterial rinses, and is scheduled for professional plaque control in the office as follows: every week for first month, bimonthly for second month every 3 month thereafter.
  30. 30. TYPES OF PERIODONTAL REGENERATION Non graft associated new attachment Graft associated new attachment • The rationale and techniques that must be considered for a successful outcome in periodontal bone regeneration are; (1) the removal of the junctional and pocket epithelium (2) the prevention of their migration into the healing area after therapy (3) clot stabilization, wound protection, and space creation (4) guided tissue regeneration (5) the biomodification of the root surface (6) selection of the proper graft materials (7) biologic mediators (growth factors) and enamel matrix proteins to enhance or direct healing (8) the combination of graft materials, membranes, and biologic mediators used to enhance new attachment and bone growth.
  31. 31. NON GRAFT ASSOCIATED NEW ATTACHMENT 1. Removal of Junctional and Pocket Epithelium The presence of junctional and pocket epithelium has been perceived as a barrier to successful therapy because its presence interferes with the direct apposition of connective tissue and cementum, thus limiting the height to which periodontal fibers can become inserted to the cementum. Methods recommended to remove the junctional and pocket epithelium: • curettage • chemical agents • ultrasonics • lasers • surgical techniques.
  32. 32. • In subgingival curettage, all the epithelium lining the pocket together with the underlying inflammatory tissue as well as the epithelial attachment is removed. • The tooth surface is carefully planed and the gingival tissue is carefully readapted to the tooth, a blood clot being allowed to form in the operated area. • If the procedure is successful, the blood clot undergoes organization with production of connective tissue. • A layer of cementum forms on the tooth surface while bone deposition takes place on the alveolar side, both surfaces having periodontal fiber insertions. • The depth of the crevice will then be situated at a new location on the tooth, lying occlusally to the point of formation of the new tissue (By Henry M. Goldman 1949)
  33. 33. Surgical Techniques • The excisional new attachment procedure 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. • Glickman and Prichard have advocated performing a gingivectomy to the crest of the alveolar bone and debriding the defect.
  34. 34. (2) Prevention of Epithelial Migration • Elimination of junctional and pocket epithelial may not be sufficient because the epithelium from the excised margin may rapidly proliferate to become interposed between the healing connective tissue and the cementum. Achieved by: • excluding the epithelium by amputating the crown of the tooth and covering the root with the flap (“root submergence”). • total removal of the interdental papilla covering the defect and its replacement with a free autogenous graft obtained from the palate. During healing, the graft epithelium necroses and is slowly replaced by proliferating epithelium from the gingival surface. The graft simply delays the epithelium from proliferating into the healing area. • coronally displaced flaps, which increase the distance between the epithelial wound edge and the healing area.
  35. 35. 3. Clot Stabilization, Wound Protection, and Space Creation. • Graft materials, barrier membranes, and coronally displaced flaps to the fact that these techniques protect the wound and create a space for undisturbed and stable maturation of the clot. • This hypothesis suggests that preservation of the root surface fibrin clot interface prevents apical migration of the gingival epithelium and allows for connective tissue attachment during the early wound-healing period. • The space can be created by using a titanium-reinforced expanded polytetrafluoroethylene (ePTFE) membrane to prevent its collapse. • For the study of reconstructive techniques, these membranes were placed over experimentally created supraalveolar bone defects in dogs, and considerable bone reconstruction was reported..
  36. 36. 4. Guided Tissue Regeneration • The method for the prevention of epithelial migration along the cemental wall of the pocket and maintaining space for clot stabilization that has gained wide attention is the guided tissue regeneration (GTR). – This method derives from the classic studies of Nyman, Lindhe, Karring, and Gottlow and is based on the assumption that only the periodontal ligament cells have the potential for regeneration of the attachment apparatus of the tooth.
  37. 37. HISTORICAL PERSPECTIVE • In 1976 – Melcher described the basic concept that led to development of clinical technique of GTR. He said that cells that repopulate the root surface after pdl surgery will determine the type of attachment that forms on the root during healing. • In 1982 – Nyman et al first described the clinical procedure of GTR using a non absorbable barrier. • In 1982 – W.L. Gore and associates, began investigating materials that would limit the migration of epithelial around dental implants and teeth.
  38. 38. • George Winter proposed that specific porosities in grew with connective tissue and stopped or slowed the migration of epithelial -> called, this phenomenon as “contact inhibition’. • Following this, Nyman, lindhe and Karring introduced the Millipore cellular acetate filter paper which provided the first human histological evidence of pdl regeneration in response to GTR.
  39. 39. Principle • Guided tissue regeneration" (GTR) is based on a principle of guiding the proliferation of the various periodontal tissue components during healing following periodontal surgery. • GTR involves the placement of a barrier covering the periodontal defect in such a way that the gingival tissues (epithelium and connective tissue) are prevented from contacting the root surface during healing. • At the same time, a space is formed between the barrier and the root allowing periodontal ligament cells (PDL cells) to produce new connective tissue attachment and bone cells to produce new bone.
  40. 40. Indications Narrow 2 or 3 walled infrabony defects. • Circumferential defects. • Class II furcation defects accompanied by a medium to long root trunk. • Early class III furcation • Augmentation of ridge deficiencies. • Coverage of root recession. • Osseous fill around immediate implant placement sites. • Repair of apicoectomy defects. • Repair of osseous defects associated with failing implants.
  41. 41. Contraindications - Patient with poor oral hygiene. - Generalised horizontal bone loss. - Class III furcation defects or furcation with short root trunks. - Advanced defects with a minimum amount of remaining periodontium. - Multiple adjacent defects. - Areas with inadequate zone of attached gingiva. - Any medication or disease or condition that interferes with healing potential or ability to perform home care. - In case of Flap perforations and cases in which flap vascularity will be compromised.
  42. 42. Ideal characteristics of the barrier membrane 1)The material should be biocompatible. 2)It should have acceptable handling properties. 3)Should have the ability to adhere to the root surface. 4)Should promote tissue coverage with reduced barrier exposure rates. 5)Should resist bacterial contamination. 6)Should promote selective cell proliferation with in the defect. 7)Should absorb at a rate that parallels regenerative tissue formation i.e 4 weeks – 6 months.
  43. 43. Classification of GTR materials 1) Nonbioresorbable membrane. Expanded polytetrafluoroethylene (ePTFE) Obtained in different shapes and sizes to suit proximal space and facial/lingual surfaces of the furcation.
  44. 44. Bioresorbable membranes: 1)Natural Biomaterials: Collagen [KOKEN tissue guide (Koken),Paroguide (Lyon)], Freeze dried duramater, Sheets of demineralized laminar or cortical bone, Oxidised cellulose. Cargile membrane. 2)Synthetic Polymers Polylactic acid and polyglycollic acid polymer Calcium sulphate
  45. 45. Non Resorbable Membranes • They maintain their structural integrity, and, consequently, the essential features they possess, for as long as they are left in the tissues. • This compositional and design stability provides the operator with complete control over time of application, with the potential to minimize variation in effectiveness (Tatakis et al. 1999). • They require a second surgical procedure for removal.
  46. 46. Disadvantages: • Patient acceptance, time, cost, and possible morbidity associated with any surgical procedure. • The function of the barrier membrane is temporary and, once the function is completed, there is no longer any need for it to remain in place. • Risk of latent or postsurgical bacterial contamination.
  47. 47. POLYTETRAFLUOROETHYLENE MEMBRANES • Fluorocarbon polymer with exceptional inertness and biocompatibility. • Solid polytetrafluoroethylene is nonporous, does not allow tissue ingrowth and does not elicit a foreign-body reaction in tissue. • Expanded polytetrafluoroethylene (ePTFE) polytetrafluoroethylene subjected to tensile stress during manufacture, resulting in differences in physical structure. • It has a porous microstructure of solid nodes and fibrils.
  48. 48. • The size of the resulting fibrils and the spacing of the interconnecting nodes can be controlled through changes in the processing conditions. • The optimal size of fibrils and internodal distance depends on the type of application the device is intended for. • Three different ePTFE membrane qualities with different porosities (internodal distances <8, 20–25 and 100 mm) were studied. • The material with the smallest internodal distance did not integrate well with the surrounding soft tissue, leading to a lack of stabilization of the membrane and more soft tissue ingrowth from the side (Zellin and Linde 1996).
  49. 49. • The use of expanded polytetrafluoroethylene devices has been associated with minor complications such as : • Pain, purulence • Swelling and tissue sloughing, with an incidence slightly higher than that reported for conventional periodontal surgery (Tatakis et al. 1999).
  50. 50. Titanium reinforced ePTFE • Titanium-reinforced membranes consist of a double layer of ePTFE with a titanium framework interposed. • The rigidity of the reinforced expanded polytetrafluoroethylene device supports improved space provision and maintenance. • It is used in situations where bone formation is desired in large defects or supracrestal defects, where conventional pTFE donot adequately maintain space unless unless supported by grafting materials.
  51. 51. Have been used successfully in • Vertical ridge augmentation • Large defects in the alveolar process • Intrabony defects and in gingival recessions
  52. 52. SURGICAL PROCEDURE • It is important to note that the surgical principles and procedures that apply to nonresorbable membranes also apply to resorbable barriers. • The main differences will be in postoperative considerations and a lack of a need for a secondary removal surgery in most cases.
  53. 53. 1. Raise a mucoperiosteal flap with vertical incisions, extending a minimum of two teeth anteriorly and one tooth distally to the tooth being treated. 2. Debride the osseous defect and thoroughly plane the roots. 3. Trim the membrane to the approximate size of the area being treated. The apical border of the material should extend 3 to 4 mm apical to the margin of the defect and laterally 2 to 3 mm beyond the defect. The occlusal border of the membrane should be placed 2 mm apical to the cementoenamel junction.
  54. 54. 4. Suture the membrane tightly around the tooth with a sling suture. 5. 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. 6. The use of periodontal dressings is optional, and the patient is placed on antibiotic therapy for 1 week. 7. After 4 to 6 weeks, the margin of the membrane may become exposed. The membrane is removed carefully, minimizing trauma to the underlying tissue. If it cannot be removed easily, the tissues are anesthetized, and the material is surgically removed using a small flap. • The results obtained with the GTR technique are enhanced when the technique is combined with grafts placed in the defects
  55. 55. An illustration of “theoretical” complete regeneration following Goretex membrane placement. In reality at six weeks, when membranes were removed, the regenerated tissue was a red gelatinous tissue which did not resemble architecturally the definitive regenerated structures: this process takes approximately 12 months. The placement of an ePTFE membrane. The open micropore surface is designed to slow down the migration of large (relative to fibroblasts) epithelial cells. The occlusive “skirt” draped over the alveolus had a smaller micropore structure designed to prevent slender gingival fibroblasts from traversing the membrane onto the root surface.
  56. 56. BIORESORBABLE MEMBRANES • They were intended to omit the surgery of membrane retrieval and reduce the treatment time (El Helow and El Askary 2008). • They include collagens such as: Bio-Guide (Geistlich Biomaterials, Wolhusen, Switzerland) Bio-mend (cross-linked bovine type I collagen) Polyglactin 910 knitted mesh such as Vicryl (Ethicon, Norderstedt, Germany) Polylactic acid such as Atrisorb (dl-lactide polymer,Atrix Laboratories Inc., Fort Collins, CO); 37% polylactic acid 63% pyrrolidine Polyglycolic acid
  57. 57. • Copolymer of polylactic and polyglycolic acid such as Resolut XT (Gore and associates Inc., Flagstaff, AZ) • Freeze-dried fascia lata • Laminar bone barrier (Lambone, Pacific Coast Tissue Bank, Los Angeles, CA) made from 100- to 300-mm thick sheets of demineralized, freezeddried ethylene oxide sterilized cortical bone • Polyhydroxybutyrate (PHB) • PHB copolymerized with hydroxyvalerate • PHB copolymerized with hydroxyvalerate and polyglactin 910
  58. 58. Advantages • No need for membrane removal surgery • Simplified surgical procedure with an implant system with two-stage surgical approach • Wider range of surgical techniques possible at abutment connection (which coincides with membrane removal for non resorbable membranes) • Better cost-effectiveness • Decreased patient morbidity
  59. 59. Disadvantages • Uncontrolled duration of barrier function • Resorption process possibly interfering with wound healing and bone regeneration • Need for membrane supporting material. • By their inherent nature, absorbable barriers offer limited control over the length of application. • This is because the disintegration process starts upon placement in the tissues, and the ability of each individual patient to degrade a particular biomaterial may vary significantly, particularly for materials requiring enzymatic degradation (such as collagen).
  60. 60. • Absorbable devices should maintain their in vivo structure for at least 4 weeks, but because of their biodegradability, absorbable devices elicit inevitable and necessary tissue reactions that may influence wound healing. • Ideally, these inflammatory reactions should not compromise the intended regenerative outcome.
  61. 61. Collagen • Collagen forms a 3-D cellular matrix of all tissues. • Collagen surrounds the cells and gives each tissue its characteristic structure, texture and shape. • It is the structural building block of the body. • The subunit chains of collagen are synthesized from free amino acids, mostly in fibroblasts and osteoblasts, by the ribosomes of the rough endoplasmic reticulum as larger pro-chains. • Proline and lysine residues are selectively hydroxylated enzymatically, and the prochains are often glycosylated during this stage.
  62. 62. • A type I collagen guided tissue regeneration membrane approved for clinical use is manufactured from collagen derived from bovine deep flexor (Achilles) tendon (BioMendTMF). • This membrane is semiocclusive (effective pore size 0.004 mm), and is paper-white in the dry state with a surface texture similar to leather. • In cross-section, the composition of condensed, laminated sheets is visible. • The BioMend membrane becomes translucent when hydrated but remains nonslippery and adaptable to the tooth root, which facilitates placement.
  63. 63. • OsseoQuest (Gore), a combination of polyglycolic acid, polylactic acid, and trimethylene carbonate that resorbs at 6 to 14 months • BioGuide (Osteohealth), a bilayer porcine-derived collagen; Atrisorb (Block Drug), a polylactic acid gel; and BioMend (Calcitech), a bovine Achilles tendon collagen that resorbs in 4 to 18 weeks. Of these, BioGuide is the most popular resorbable membrane.
  64. 64. Other Bioresorbable membranes • Dura mater • Cargile membranes • Oxidized cellulose mesh • Laminar bone • Acellular dermal matrix (ADM),
  65. 65. SYNTHETIC PRODUCTS • Synthetic resorbable materials are usually organic aliphatic thermoplastic polymers. • The materials most commonly used are poly-a-hydroxy acids, which include polylactic polyglycolic acid and their copolymers. • They get hydrolysed to final products water and carbon dioxide.
  66. 66. MEMBRANE SELECTION: NONRESORBABLE OR RESORBABLE. 1. Maintain the sterility of the material. 2. Choose a size that offers the most ideal design for defect coverage. 3. Shape the material with scissors. Avoid leaving sharp edges. 4. Enough material should be left to permit lateral and interproximal suturing while leaving at least 3 mm apical and lateral overextension of the defect margin. 5. The material should fit smoothly, avoiding folds, overlaps, and protrusions, which may compromise the overlying gingival tissue. 6. In either periodontal or bony ridge defects, the amount of space beneath the material determines the maximum potential regeneration. Without space maintenance, regeneration is not possible.
  67. 67. 5. Biomodification of Root Surface. • Changes in the tooth surface wall of periodontal pockets (e.g., degenerated remnants of Sharpey’s fibers, accumulation of bacteria and their products, disintegration of cementum and dentin) interfere with new attachment. • Although these obstacles to new attachment can be eliminated by thorough root planing, the root surface of the pocket can be treated to improve its chances of accepting the new attachment of gingival tissues.
  68. 68. Citric Acid • Applied to the roots to demineralize the surface and attempts to induce cementogenesis and attachment of collagen fibers. • Following actions of citric acid have been reported: 1. Accelerates healing and new attachment formation occur after surgical detachment of the gingival tissues and demineralization of the root surface. 2. After root planing the acid produces a 4um-deep demineralized zone with exposed collagen fibers. 3. Removes smear layer and exposes dentinal tubules. 4. Citric acid has also been shown 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.
  69. 69. • The recommended technique is as follows: 1. Raise a mucoperiosteal flap. 2. Thoroughly instrument the root surface, removing calculus and underlying cementum. 3. Apply cotton pledgets soaked in a saturated solution of citric acid (pH 1), and leave on for 2 to 5 minutes. 4. Remove pledgets, and irrigate root surface profusely with water. 5. Replace the flap and suture.
  70. 70. Disadvantages : – Because of its low pH vitality of surrounding periodontal tissues may be compromised (Blomlof & Lindskog 1995). – It has been reported to cause gingival recession & discouraged alveolar bone growth – Immediate (within 20s) necrotizing effects on both mucosal flaps and periodontal tissues (Blomlof et al. 1995).
  71. 71. Ethylenediaminetetra acetic acid (EDTA) – EDTA is the only one which exclusively exerts its demineralizing effect through chelating divalent cations at neutral pH. – Different concentrations of EDTA have been used 1.5%, 5%, 15% & 24%. – The supersaturated (24%) solution is more effective when applied for 2 minutes in order to obtain an acceptable smear removing & collagen exposing effect.
  72. 72. Fibronectin – Fibronectin is the glycoprotein that fibroblasts require to attach to root surfaces. The addition of fibronectin to the root surface may promote new attachment . (Caffesse et al.1987, Terranova 1982) – It is a biologic mediator that enhances the tissue response in the early phases of wound healing, prevents separation of the flap, and favors hemostasis and connective tissue regeneration.
  73. 73. Tetracycline • TETRACYCLINE increases the binding of fibonectin, which stimulates fibroblast attachment and growth while suppressing epithelial cell attachment and migration. • Tetracycline application for 5 minutes has: –demineralizing effect –removes smear layer –expose dentinal tubules (Wikesjo) • Baker et al. (1983) demonstrated the ability of tetracycline to bind to dentin. The bound tetracycline is released and serves as a local antimicrobial delivery vehicle for up to 14 days.
  74. 74. Selection of the proper graft material.
  75. 75. Autografts Allografts Xenografts • Bone graft materials are also evaluated based on their osteogenic, osteoinductive, or osteoconductive potential. • Osteogenesis refers to the formation or development of new bone by cells contained in the graft. • Osteoinduction is a chemical process by which molecules contained in the graft (e.g., bone morphogenetic proteins) convert the neighboring cells into osteoblasts, which in turn form bone. • Osteoconduction is a physical effect by which the matrix of the graft forms a scaffold that favors outside cells to penetrate the graft and form new bone. BONE GRAFTS
  76. 76. • Schallhorn defined the considerations that govern the selection of a material as follows: 1. biologic acceptability 2. Predictability 3. clinical feasibility 4. minimal operative hazards 5. minimal postoperative 6. sequelae, and patient acceptance. It is difficult to find a material with all these characteristics • All grafting techniques require presurgical scaling, occlusal adjustment as needed, and exposure of the defect with a fullthickness flap. • The flap technique best suited for grafting purposes is the papilla preservation flap because it provides complete coverageof the interdental area after suturing.
  77. 77. Autogenous bone grafts Bone from Intraoral Sites In 1923, Hegedüs attempted to use bone grafts for the reconstruction of bone defects produced by periodontal disease. • Bone obtained from the same individual. • AUTOGRAFTS retain some cell viability and are considered to promote bone healing. • They are gradually resorbed and replaced by new viable bone. • Bone Harvested from: 1. healing extraction wounds 2. bone from edentulous ridges 3. bone trephined from within the jaw without damaging the roots 4. newly formed bone in wounds especially created for the purpose 5. bone removed from tuberosity and the ramus 6. bone removed during osteoplasty and ostectomy.
  78. 78. a) Cortical bone chips – These are not used today because they are generally much longer particles 1,559.6 × 183 mm and have a higher potential for sequestration (Zaner and Yukna 1984). b) Osseous Coagulum. Robinson described a technique using a mixture of bone dust and blood that he termed “osseous coagulum.” • The technique uses small particles ground from cortical bone. • The advantage of the particle size is that it provides additional surface area for the interaction of cellular and vascular elements. • Sources of the graft material: the lingual ridge on the mandible, exostoses, edentulous ridges, the bone distal to a terminal tooth, bone removed by osteoplasty or ostectomy, and the lingual surface of the mandible or maxilla at least 5 mm from the roots. • Bone is removed with a carbide bur #6 or #8 at speeds between 5000 and 30,000 rpm, placed in a sterile dappen dish and used to fill the defect. • Advantage: Ease of obtaining bone from a area already exposed during surgery. • Disadvantages are its relatively low predictability and the inability to procure adequate material for large defects.
  79. 79. c. Bone Blend • Bone blend is the combination of cortical and cancellous bone. • The bone blend technique uses an autoclaved plastic capsule and pestle. Bone is removed from a predetermined site, triturated in the capsule to a workable, plasticlike mass, and packed into bony defects. • Froum et al found osseous coagulum–bone blend procedures to be at least as effective as iliac autografts and open curettage.
  80. 80. D. Cancellous Bone Marrow Transplants. Cancellous bone can be obtained from the maxillary tuberosity, edentulous areas, and healing sockets. • After a ridge incision is made distally from the last molar, bone is removed with a curved rongeur. • Edentulous ridges can be approached with a flap, and cancellous bone and marrow are removed with curettes, back-action chisels or trephine . • Extraction sockets are allowed to heal for 8 to 12 weeks before reentering and removing the newly formed bone from the apical portion, which is used as the donor material. E. Bone Swaging • The bone swaging technique requires an edentulous area adjacent to the defect, from which the bone is pushed into contact with the root surface without fracturing the bone at its base. • Bone swaging is technically difficult, and its usefulness is limited
  81. 81. Bone from Extraoral Sites • In 1923, Hegedüs also pioneered the use of extraoral sites as a source of bone for grafting into periodontal osseous defects, using bone from the tibia. • Schallhorn and Hiatt revived this approach in the 1960s using the iliac crest • Iliac Autografts are no longer used because of : 1. postoperative infection 2. bone exfoliation 3. sequestration 4. varying rates of healing 5. root resorption, 6. rapid recurrence of the defect 7. increased patient expense and difficulty in procuring the donor material.
  82. 82. Among the biomaterials, autogenous bone has been adopted as the gold standard because: (1) Autograft bone includes cells participating in osteogenesis. (2) A tissue reaction is induced without inducing immunological reactions. (3) There is a minimal inflammatory reaction. (4) There is rapid revascularization around the graft particles . (5) A potential release of growth and differentiation factors sequestered within the grafts.
  83. 83. ALLOGRAFTS • Allografts are obtained from a different individual of the same species. • They are foreign to the patient and therefore have the potential to provoke an immune response. • Attempts have been made to suppress the antigenic potential of allografts and xenografts by radiation, freezing, and chemical treatment. • Bone allografts are commercially available from tissue banks. • They are obtained from cortical bone within 12 hours of the death of the donor, defatted, cut in pieces, washed in absolute alcohol, and deep-frozen. • The material may then be demineralized, and subsequently ground and sieved to a particle size of 250 to 750 μm and freeze-dried. • Finally, it is vacuum-sealed in glass vials.
  84. 84. • They include : 1 . Freeze-dried bone allografts (FDBA) 2. Demineralized freeze-dried bone allograft (DFDBA). • FDBA is a mineralized bone graft, which through the manufacturing process loses cell viability and,therefore, is supposed to promote bone regeneration through osteoconduction (Goldberg & Stevenson 1987). • The freeze drying also markedly reduces the antigenicity of the material. (Turner & Mellonig 1981, Quattlebaum et al. 1988). • Mellonig, Bowers, and co-workers reported bone fill exceeding 50% in 67% of the defects grafted with freeze-dried bone allograft (FDBA) and in 78% of the defects grafted with FDBA plus autogenous bone. • Histologic evidence- implantation of FDBA in intrabony defects yielded no periodontal regeneration but resulted in a long epithelial attachment on the previously diseased root surface (Dragoo & Kaldahl 1983).
  85. 85. Demineralized freeze-dried bone allograft Urist have established the osteogenic potential of DFDBA. Demineralization in cold, diluted hydrochloric acid exposes the components of bone matrix, which are closely associated with collagen fibrils and have been termed bone morphogenetic proteins (BMPs). This enhances its osteogenic potential. • BMPs have the ability to induce host cells to differentiate into osteoblasts. (Urist & Strates 1970, Mellonig et al. 1981). • Histologic evidence - of regeneration following grafting with DFDBA was provided by Bowers et al. • Complete regeneration with new cementum, periodontal ligament and bone amounting to 80% of the original defect depth was reported at sites treated with DFDBA, which was considerably more than that observed in defects treated with surgical debridement alone.
  86. 86. XENOGRAFTS • Xenografts are grafts shared between different species. • Currently, there are two available sources of xenografts used as bone replacement grafts in periodontics: bovine bone and natural coral. • Recently, porcine bone xenografts have also been described. • Xenografts are osteoconductive, readily available and risk free of disease transmission. • New processing and purification methods have been utilized which make it possible to remove all organic components from a bovine bone source and leave a non-organic bone matrix in an unchanged inorganic form. • (e.g. Bio-Oss, Endobone , Laddec®, Ost Development,on- Apatite®, Bio-Interfaces Inc.).
  87. 87. Anorganic Bovine Bone Xenograft • The BDX is a xenograft consisting of deproteinized, sterilized bovine bone with 75–80% porosity and a crystal size of approximately 10 mm in the form of cortical granules. • Regarding both the chemical and physical features, BDX is considered identical to the human bone. • It has demonstrated efficacy for : 1. Reconstruction of atrophied alveolar ridges 2. around endosseous implants 3. sinus floor elevation procedures 4. peri-implantitis defects 5. large periapical lesion.
  88. 88. • A composite of autogenous bone and bone substitute is widely used in oral surgery procedures because it combines the osteogenic property of autogenous bone and the osteoconductive property of BDX . • It contains osteogenic cells and provides a scaffold and internal pores for bone cells to grow and remineralize to new bone. • Bio-Oss (Osteohealth) has been successfully used both for periodontal defects and in implant surgery.
  89. 89. • Bio-OssR (Osteohealth Co., Shirley, NY) is a natural, nonantigenic, porous bone mineral matrix. • It is produced by the removal of all organic components from bovine bone. • It is available in cancellous (spongiosa) and cortical granules and blocks. • Bio-Oss undergoes a low-heat (3,000°C) chemical extraction process by which all organic components are removed, but maintains the natural architecture of bone. • Implantation of Bio-Oss® resulted in pocket reduction, gain of attachment and bone fill in periodontal defects to the same extent as that of DFDBA (Richardson et al. 1999). • Human histology and animal experiments have also suggested a beneficial effect of placing bovine bone-derived biomaterials in periodontal bone defects.
  90. 90. • Periodontally, Bio-Oss has been used as a graft material covered with a resorbable membrane (BioGuide). The membrane prevents the migration of fibroblasts and connective tissues into the pores and between the granules of the graft. • Histologic studies of this technique have shown significant osseous regeneration and cementum formation.
  91. 91. • Bio-Oss CollagenR consists of Bio-Oss Spongiosa granules (0.25–1 mm) with the addition of 10% highly purified porcine collagen. • The collagen component allows Bio-Oss Collagen to be easily adapted into the defect. • The cohesion of the particles is ensured, even without a membrane. • The collagen component is resorbed within 4–6 weeks.
  92. 92. Coralline Calcium Carbonate • Natural coral graft substitutes are derived from the exoskeleton of marine madreporic corals. • The structure of the commonly used coral, Porites, is similar to that of cancellous bone, and its initial mechanical properties resemble those of bone. • Depending on the pre-treatment procedure, the natural coral turns into non-resorbable porous hydroxyapatite or to a resorbable calcium carbonate. • Implantation of coralline porous hydroxyapatite in intrabony periodontal defects in humans produced more probing pocket depth reduction, clinical attachment gain and defect fill than non-grafting.
  93. 93. • The main differences between natural coral and bone include the organic content and the mineral composition. • One third of the total weight in bone is composed of organic components, while the coral organic content is limited to 1– 1.5%. • The mineral composition of bone is mainly hydroxyapatite and amorphous calcium phosphate associated with calcium carbonate, while coral is essentially calcium carbonate (Demers et al. 2002). • Biocoral is a commercially available product. • Histologic evidence that grafting of natural coral may enhance the formation of true new attachment.
  94. 94. ALLOPLASTIC MATERIALS • Alloplastic materials are synthetic, inorganic, biocompatible and/or bioactive bone graft substitutes which are claimed to promote bone healing through osteoconduction. • There are four kinds of alloplastic materials, which are frequently used in regenerative periodontal surgery: 1. hydroxyapatite (HA), 2. beta tricalcium phosphate (13-TCP), 3. polymers, 4. bio-active glasses (bio-glasses).
  95. 95. Hydroxyapatite (HA), • Synthetic hydroxyapatite, Ca10(PO4)6(OH)2, has been available for more than 30 years. It is the primary mineral found in bone. • Synthetic hydroxyapatite can be found as porous or non porous. • HAs present remarkable biocompatibility with little inflammatory response when implanted within connective and bone tissue. • The HA products used in periodontology are of two forms: 1. a particulate non-resorbable ceramic form (e.g.Periograf®, Calcitite) 2. a particulate, resorbable non-ceramic form
  96. 96. • Histologic evidence showed that bone formation was limited and that a true new attachment was not formed consistently after grafting of intrabony periodontal defects with HA. • The majority of the HA particles were embedded in connective tissue and new bone was only observed occasionally around particles in close proximity to host bone. • A junctional epithelium was lining the major part of the roots.
  97. 97. • The advantages of using hydroxyapatite are: (1) immunoreaction 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 adsorption of hydroxyapatite, if any, is slight and slow and is replaced by bone. (4) cement fixation performed on a layer of hydroxyapatite particles prevents the harmful influence of polyethylene wear particles of cement interface. The clinical disadvantages hydroxyapatite particles are that they tend not to stay in place in a bleeding site, and there is a relatively slow restoration of bone within the assemblage of particles (Oonishi et al. 1997).
  98. 98. Various types of HA 1. The polycrystalline ceramic form of pure densely sintered HA is non- resorbable, osteoconductive, has a low microporosity and act primarily as inert biocompatible fillers. It is prepared in relatively large particle size (18–40 mesh). 2.The coralline porous non-resorbable hydroxylapatite is a replica of a marine coral skeleton, Porites. After the organic components of the coral have been removed, the aragonite of the coral skeleton is converted to HA by treatment with an ammonium phosphate at elevated temperature and pressure. This hydroxylapatite is formed as small crystals
  99. 99. 3. The resorbable nonceramic hydroxylapatite is highly microporous, non-sintered (nonceramic), composed of small particles measuring 300–400 mm (35–60 mesh), with a controlled, predictable rate of resorption. As the material resorbs, it acts as a mineral reservoir and predictably induces new bone formation via osteoconductive mechanisms. 4. Nanocrystalline hydroxyapatite (NHA). Researchers have found that nanoparticular hydroxyapatite not only provides the benefits of traditional hydroxyapatites, but also resorbs. 5. Fluoroapatite: The commercially available porous biomaterial FRIOSR AlgiporeR (Friadent GmbH, Mannheim, Germany) is manufactured from calcifying marine algae (Corallina officinalis). The particles contain a pore system with a mean diameter of 10 mm that is periodically septated (mean interval 30 mm) and interconnectively microperforated (mean diameter of perforations 1 mm).
  100. 100. b- tricalcium phosphate • The crystal structure of alpha tricalcium phosphate (a-Ca3(PO4)2 is monoclinic and consists of columns of cations, while the beta tricalcium phosphate has a rhombohedral structure. • The former is formed by heating the latter above 1,180°C and quenching in air to retain its structure. • Alpha form is less stable than beta and forms the stiffer material calcium-deficient hydroxyapatite when mixed with water. • Calcium phosphates can be bound to collagen carriers or mixed with fibrin. The concept is that collagen and fibrin form a network on which minerals can crystallize. • Collagen can also bind to extracellular matrix (ECM) proteins of importance in the mineralization process. • Histologic evidence Showed that 13-TCP is rapidly resorbed or encapsulated by connective tissue, with minimal bone formation and no periodontal regeneration.
  101. 101. POLYMERS • There are two polymer materials that have been used as bone graft substitutes in the treatment of periodontal defects: 1. a non-resorbable, calcium hydroxide coated co-polymer of poly-methyl-methacrylate (PMMA) and poly- hydroxylethyl-methacrylate (PHEMA) which is often referred to as HTR (hard tissue replacement) e.g. HTRTM 2. resorbable polylactic acid (PLA) polymer e.g.Driloc ®.
  102. 102. • Histologic evaluation revealed that grafting of osseous periodontal defects with HTR does not promote periodontal regeneration. • The HTR particles were most frequently encapsulated by connective tissue with only scarce evidence of bone formation. • Healing resulted in a long junctional epithelium along the root surface, and true new attachment formation was not observed. • When PLA particles were implanted into intrabony defects in humans and compared with DFDBA or surgically debrided controls, it was found that the healing results were less favorable than after flap operation alone, both in terms of clinical parameters (PPD and PAL gain), and in terms of bone fill.
  103. 103. Bioactive Glass (BG) • Bio-glasses are composed of SiO2, Na2O, P2O5 and are resorbable or not resorbable depending on the relative proportion of these components. • When bio-glasses are exposed to tissue fluids, a double layer of silica gel and calcium phosphate is formed on their surface. • Through this layer the material promotes absorption and concentration of proteins used by osteoblasts to form extracellular bone matrix which theoretically may promote bone formation . • Commercially available bio-glasses in particulate form, and theoretically resorbable, have been proposed for periodontal treatment (e.g. PerioGlass'j, BioGran®.)
  104. 104. • The bioactive glass particles formed a cohesive mass when wetted with blood, which allowed very easy manipulation and packing into the extraction sockets or periodontal defects. • This transparent bioactive material has proven ability to bond to connective tissue and bone without an intervening fibrous connective tissue interface. • Upon contact with body fluid, there is an immediate exchange of ions which results in a physiochemical bond between Bioglass, soft tissue and bone. • The ion exchange creates an environment resulting in the formation of a hydroxyl-carbonate apatite layer (HCA), a biological apatite identical to the mineral phase of bone, which allows for more rapid repair and regeneration of bone than other synthetic graft materials. • It was showed that bioactive glass several antibacterial effect against on a large panel of clinically important bacterial species (A. actinomycetemcomitans, P. gingivalis, Actinomyces naeslundii, Fusobacterium nucleatum, Prevotella intermedia, Streptococcus mutans, and Streptococcus sanguis, Candida albicans)
  105. 105. • Bioactive glass is a particulate bioactive ceramic, which has the ability to bond to bone tissue and enhance bone growth because of its osteoconductive properties. • It also has an osteostimulatory effect showing bone growth within eroded particles. • These islands of newly formed bone tissue function as nuclei for further bone growth and enhance the repair of osseous defects.
  106. 106. Enamel matrix protein (Emdogain) • Enamel matrix protein derivatives obtained from developing porcine teeth has been approved by the FDA and is marketed under the trade name Emdogain. • The material is a viscous gel consisting of enamel-derived proteins from tooth buds in a polypropylene liquid; 1 ml of a vehicle solution is mixed with a powder and delivered by syringe to the defect site. • 90% of the protein in this mixture is amelogenin, with the rest primarily proline-rich non-amelogenins, tuftelin, tuft protein, serum proteins, ameloblastin, and amelin. 108
  107. 107. • The use of enamel matrix derivatives (EMD) for periodontal regeneration has been suggested because it is thought that this process might mimic way these materials behave in normal tooth development. • Purified enamel matrix proteins have been extracted from porcine developing enamel. • The enamel matrix proteins, mainly amelogenin, are secreted by Hertwig’s epithelial root sheath during tooth development and are known to induce acellular cementum formation. • These protein believed to enhance periodontal regeneration by promoting bone cell attachment & cell spreading & enhance the proliferation of more immature bone cells while stimulating the differentiation of more mature bone cells. • Enamel matrix derivative enhances human periodontal ligament fibroblast cell woundhealing.
  108. 108. • The technique, as described by Mellonig, is as follows: 1. Raise a flap for regenerative purposes 2. Remove all granulation tissue and tissue tags, exposing the underlying bone, and remove all root deposits by hand, ultrasonic scaling, or both. 3. Completely control bleeding within the defect. 4. Demineralize the root surface with citric acid pH 1, or preferably with 24% ethylenediaminetetracetic acid(EDTA Biora) pH 6.7 for 15 seconds. This removes the smear layer and facilitates adherence of the Emdogain. 5. Rinse the wound with saline and apply the gel to fully cover the exposed root surface. Avoid contamination with blood or saliva.
  109. 109. 6. Close the wound with sutures. Perfect abutment of the flaps is necessary; if this cannot be obtained, correct the scalloping of the gingival margin or perform a slight osteoplasty. Although placement of the dressing is optional, it may protect the wound Systemic antibiotic coverage for 10 to 21 days is recommended (Doxycycline, 100 mg daily).
  110. 110. Heijl et al compared the use of enamel matrix derivatives with a placebo in 33 patients with 34 paired test and control sites, mostly one-wall and two-wall defects, followed for 3 years. They found a statistically significant radiographic bone gain of 2.6 mm. Froum et al reported that use of Emdogain resulted in a reduction in probing depth of 4.94 mm, increase in attachment level of 4.26 mm, and bone fill of 3.83 mm (74% of defects). In a histologic study of 10 defects in 8 patients, Yukna and Mellonig reported evidence of regeneration (new cementum, bone, and periodontal ligament) in three specimens, new attachment (connective tissue attachment, adhesion only) in three specimens, and a long junctional epithelium in four specimens.
  111. 111. GROUP MATERIAL EFFECT ADVANTAGES DISADVANTAGE S AUTOLOGO US Osteogenic Osteoinductive Osteoconductive Viable cells, growth factors, Intraoralavailability Rapid resorption potentially inducing root resorptions ALLOGENIC DFDBA Osteoinductive Osteoconductive Osteogenic potential by release of BMPs Antigenecity? Infection? FDBA Osteoconductive Antigenecity? Infection? XENOGENIC Bovine material Osteoconductive Similar results as for DFDBA Poor/ slow resorption Coralline Osteoconductive Long junctional epithelium, Connective tissue encapsulation
  112. 112. ALLOPLASTIC HA Osteoconductive No predictable regeneration, long junctional epithelium, connective tissue encapsulation. b-TCP Osteoconductive No predictable regeneration, fast resorption, connective tissue encapsulation. Bioactive glass Osteoconductive Long junctional epithelium, connective tissue encapsulation. Polymers Osteoconductive No regeneration
  113. 113. Biologic Mediators • BONE GRAFTS has shown some regeneration and is usually limited to the base or apical aspect of the defect and the resultant tissue formation is not sufficient in terms of quantity or predictability. • For these reasons, new therapeutic approaches for periodontal regeneration have been sought. • The recognition and appreciation that new tissues are formed by cell populations have resulted in efforts to stimulate the cells that are located in the periodontal defect. • One way to stimulate these cells is to use proteins (growth factors) that can bind to surface receptors on the cell membranes, which in turn trigger a series of events to occur that alter the genetic activity of the cell with the result that cell behavior is stimulated.
  114. 114. Growth regulatory factors for periodontal regeneration. • Growth factor is a general term to denote a class of polypeptide hormones that stimulate a wide variety of cellular events such as: 1. Proliferation 2. Chemotaxis 3. Differentiation 4. production of extracellular matrix proteins. (Terranova & Wikesjo 1987). Proliferation and migration of periodontal ligament cells synthesis of extracellular matrix differentiation of cementoblasts and osteoblasts Therefore, it is conceivable that growth factors may represent a potential aid in attempts to regenerate the periodontium. prerequisite for obtaining periodontal regeneration.
  115. 115. • These growth factors, primarily secreted by macrophages, endothelial cells, fibroblasts, and platelets, include: 1. platelet-derived growth factor (PDGF) 2. Insulin like growth factor (IGF) 3. basic fibroblast growth factor (bfGF), 4. BMP bone morhogenetic protein 5. Transforming growth factor(TGF). These biologic mediators have been used to stimulate periodontal wound healing (e.g., promoting migration and proliferation of fibroblasts for periodontal ligament formation) or to promote the differentiation of cells to become osteoblasts, thereby favoring bone formation
  116. 116. BONE MORPHOGENETIC PROTEINS • The bone morphogenetic proteins are a group of related proteins that are found in the body and are important for skeletal development. • Each of the proteins has relatively specific functions: • BMP-2 has been shown to have some of the strongest bone producing activity. • BMP-7 (also called osteogenic protein-1, or OP-1) and BMP-3 (also know as osteogenin) have also been shown to stimulate bone formation. • The BMPs were originally isolated from bovine bone by Marshall Urist 203.
  117. 117. • Bone morphogenetic proteins (BMPs) are osteoinductive factors that may have the potential to stimulate mesenchymal cells to differentiate into bone forming cells (Wozney et al. 1988). • Many carriers have been tested with the BMPs, but the binding and release kinetics using bovine type I collagen have proven to be the most useful clinically. • BMP binds tightly to the collagen within minutes and has been shown to be released over time for 2 to 3 weeks at the defect site. • The extended release kinetics likely allow the migrating into the wound site to be exposed to the growth factor.
  118. 118. Platelet Derived Growth Factor PDGFs are secreted primarily from the platelet a-granules, but also from macrophages, fibroblasts, myocytes, and endothelial and bone marrow hematopoietic cells. The PDGF family encompasses four isoforms (A, B, C and D) that always appear in a dimeric form (i.e. -AA, -BB, -AB, etc.) 1) The primary effect of platelet-derived growth factor is that of a mitogen, initiating cell division. 2) It is an important stimulator of cellular chemotaxis, proliferation and matrix synthesis 3) Plays an important role in gingival wound healing.
  119. 119. It is secreted locally during clotting by the blood platelets at the site of soft- or hard-tissue injury that stimulates a cascade of events leading to a wound-healing response. 4) It stimulates mitogenic activity and chemotaxis in osteoblasts. 5) Also stimulates the proliferation of periodontal ligament cells and acts a potent mitogen for periodontal ligament cells. 6) PDGF enhances collagen type I and osteopontin production in both periodontal ligament cells and osteoblasts
  120. 120. Insulin like Growth factor • IGF system has a fundamental role in protecting cells from programmed cell death. • IGF is found in platelets. It is released during clotting along with other growth factors present in platelets. • IGF-I is produced by osteoblasts. It thus induces proliferation and differentiation of osteoblasts with subsequent increases in osteogenesis. • IGF-I increases type I collagen formation, bone matrix apposition rate, and inhibits bone collagen degradation due to the blocking of collagenase activity by osteoblasts.
  121. 121. Transforming Growth Factor • This is stored in the alpha granules of the platelets. Three forms of TGF- β have been found. Viz. type I, II and III. • TGF-β is chemotactic for fibroblasts and promotes accumulation of fibroblasts and fibrosis in the healing process. • It has a potent effect on matrix synthesis, giving rise to increased production of collagen and fibronectin and decreased production of matrix degrading enzymes.
  122. 122. Fibroblast Growth factor • bFGF (also known as FGF-2) appears to be the most recognized form of FGF. • bFGF stimulates wound healing and tissue repair by promoting angiogenesis, cell proliferation and noncollagenous protein synthesis. • bFGF appears to be produced primarily by PDL fibroblasts and endothelial cells, while bFGF levels appear to be decreased in chronic periodontal lesions.
  123. 123. PLATELET CONCENTRATES • Platelet concentrates are blood-derived products used for the prevention and treatment of hemorrhages due to serious thrombopenia of the central origin. • Fibrin glue was originally described in 1970 and is formed by polymerizing fibrinogen with thrombin and calcium. It was originally prepared using donor plasma; however, because of the low concentration of fibrinogen in plasma, the stability and quality of fibrin glue were low.
  124. 124. PLATELET RICH PLASMA • Platelet rich plasma (PRP) is an autologous modification of fibrin glue, which has been described and used in various applications with apparent clinical success. PRP obtained from autologous blood is used to deliver growth factors in high concentrations to the site of bone defect or a region requiring augmentation. • In addition to the growth factors, PRP contains fibrinogen and a number of adhesive glycoproteins that support cell migration.
  125. 125. Technique 1.Venous blood is drawn into a tube containing an anticoagulant to avoid platelet activation and degranulation. 2. The first centrifugation is called ‘soft spin’, which allows blood separation into three layers, namely bottom-most RBC layer (55% of total volume), topmost acellular plasma layer called PPP (40% of total volume), and an intermediate PRP layer (5% of total volume) called the buffy coat. 3. Using a sterile syringe, the operator transfers PPP, PRP and some RBCs into another tube without an anticoagulant.
  126. 126. Separation of plasma (2400 rpm, 10 min). Separation of platelet-rich plasma from platelet-poor plasma (3600 rpm, 15 min).
  127. 127. 4. This tube will now undergo a second centrifugation, which is longer and faster than the first, called ‘hard spin’. This allows the platelets (PRP) to settle at the bottom of the tube with a very few RBCs, which explains the red tinge of the final PRP preparation. The acellular plasma, PPP (80% of the volume), is found at the top. 5. Most of the PPP is removed with a syringe and discarded, and the remaining PRP is shaken well. 6. This PRP is then mixed with bovine thrombin and calcium chloride at the time of application. This results in gelling of the platelet concentrate. Calcium chloride nullifies the effect of the citrate anticoagulant used, and thrombin helps in activating the fibrinogen, which is converted to fibrin and cross-linked.
  128. 128. PRP membrane Application of activated PRP on the recipient site.
  129. 129. PLATELET RICH FIBRIN • The advantages of PRF over PRP are its simplified preparation and lack of biochemical handling of the blood. • The required quantity of blood is drawn into 10-ml test tubes without an anticoagulant and centrifuged immediately. • Blood is centrifuged using a tabletop centrifuge (REMY® Laboratories) for 12 min at 2,700 rpm.
  130. 130. • The resultant product consists of the following three layers: • Topmost layer consisting of acellular PPP • PRF clot in the middle • RBCs at the bottom • Because of the absence of an anticoagulant, blood begins to coagulate as soon as it comes in contact with the glass surface.
  131. 131. Pre operative view Platelet rich fibrin clot Platelet rich fibrin membrane PRF Is placed after flap elevation
  132. 132. PRF has many advantages over PRP. • It eliminates the redundant process of adding anticoagulant as well as the need to neutralize it. • The addition of bovine-derived thrombin to promote conversion of fibrinogen to fibrin in PRP is also eliminated.
  134. 134. GRAFT INCORPORATION • Hematoma formation – Release of cytokines and growth factors • Inflammation – Development of fibrovascular tissue • Vascular ingrowth – Often extending Haversian canals • Focal osteoclastic resorption of graft • Intramembranous and/or endochondral bone formation on graft surfaces
  135. 135. • Healing processes of treated periodontal lesions express variations of repair rather than regeneration. • Specifically, the treated periodontal lesion repairs by • 1) epithelial adhesion; at times occlusal to the base of the original pocket; • 2)Collagen adhesion; most frequently observed immediately apical to the newly adhering junctional epithelium but occlusal to the marginal alveolar crest. • 3) in the infrabony portion of periodontal lesions, simultaneous and/or sequential deposition of repair cementum, functionally oriented ligament fibers and narrowing of the vertical defect by osteogenesis.
  136. 136. • With the commonly used treatments of infrabony defects, the healing responses to subcrestal debridement of these lesions with or without the use of grafts have created new interest. • The clinical observation of major significance is the recognition that such lesions "fill" to some extent and within certain limitations
  137. 137. CONCLUSION • Regenerative surgical treatment of intrabony periodontal defects results in dramatic improvements of bone loss attachment level and pocket depths that cannot be matched by other nonsurgical and surgical approaches. • These improvements are maintainable over many years if appropriate maintenance care is used. • The combined approach is most useful in large wide defects where bone grafts supply structural functions, membranes provide guided tissue and graft retention functions, and biologic agents give cellular enhancement.
  138. 138. References • Carranza’s Clinical Periodontology. 11th edition. • Clinical Periodontology & Implant Dentistry,4th& 5th Ed , Jan Lindhe
  139. 139. THANK YOU