ROOT BIOMODIFICATION

Root surface biomodification

1. ROOT SURFACE BIOMODIFICATION Presented by: Dr. Swathi B.S II MDS

2. Introduction Root Surface Changes In Periodontitis Structural changes Chemical changes Cytotoxic changes Historical Background Important terms Rationale Methods of root bio modification Mechanical Scaling &Root planning Chemical Root conditioners Enamel matrix PRP Hyluronic acid Physical Laser Conclusion &Reference CONTENTS

3. INTRODUCTION One of the important goals in periodontal therapy is to facilitate formation of new connective tissue attachment on the denuded root surface. This type of regeneration is described by the term ‘ New attachment’. It is described as embedment of new periodontal ligament fibers on to new cementum previously denuded by the periodontal disease .

4. It has also become apparent that, if the goal of periodontal regeneration is to be realized, the problem of regeneration needs to be approached from a basic biological perspective. The periodontium consists of a cell and tissue complex organized into basic components of cementum, periodontal ligament and alveolar bone. The challenge of regeneration is to reconstitute this complex onto the root surface.

5. Root must provide a substrate that does not contain cytotoxic contaminants, contain chemotactic stimulus for connective tissue cells and supports the migration and attachment of the cells for wound-healing response. Major requirement for regeneration - migration and attachment of connective tissue cells of pdl to the root surface.

6. CEMENTUM : The thin, calcified tissue of ecto mesenchymal origin covering the roots of teeth in which embedded collagen fibers attach the teeth to the alveolus. The exposed root surface alterations –inappropriate substrate for cell attachment and fiber development . Which include: loss of collagen fiber insertion contamination by bacteria and or endotoxins alterations in mineral density and composition. lack of chemotactic stimuli for periodontal regeneration .

7. As the pocket deepens Collagen fibers embedded in cementum Degenerates Penetration of Bacteria Fragmentation & Breakdown Necrotic Cementum

8. Root surface changes in the cementum The root cementum suffers Structural Chemical , and Cytotoxic changes

9. Presence of Pathogenic granules Areas of increased mineralization Areas of demineralization Structural Changes

10. Chemical Changes Mineral contents increases: mainly calcium, magnesium, phosphorus and fluoride Micro-hardness remains unchanged Forms a highly calcified layer resistant to decay may develop Ability of cementum to absorb substances may be harmful if the absorbed materials are toxic Cementum has the property of absorbing the minerals or cytotoxins when exposed to saliva

11. Cytotoxic changes Bacterial penetration can be found as deep as CEJ Bacterial products such as endotoxins have been detected in the cementum wall of periodontal pockets Cementum absorbs the endotoxins produced by periodontal pocket pathogens forming altered cementum

12. Historical Background 12 In 1833, Marshall presented a case of pocket eradication with “presumable clinical reattachment” after the use of aromatic sulfuric acid . In the 1890s; Stewart described the use of acids in conjunction with the mechanical removal of calculus and cementum. Urist (1965) that suggested that dentin following acid demineralization possessed inductive properties.

13. Urist (1973) demonstrated in a series of experiments that allogenic dentin matrix , following partial or total demineralization with O.6N HCl and transplanted in vivo in various animal models, possessed the ability to induce the formation of new bone or cementum. Register et al., in (1973) performed the first controlled study on the use of acid on root surfaces. They investigated whether new attachment,cementogenesis and osteogenesis could be induced adjacent to tooth roots demineralized in vivo. Optimal cementogenesis and new connective tissue attachment occurred when roots were demineralized with citric acid, pH 1.0 for 2 -3min. 13

14. Important terms REGENERATION: Reproduction or reconstitution of a lost or an injured part in such a way that the architecture and function of the lost or injured part is completely restored REPAIR: Restores the continuity of the diseased marginal gingiva and re-establishes a normal gingival sulcus at the same level as the base of the pre-existing pocket NEW ATTACHMENT: Fibrous attachment was restored on a root surface deprived of its connective tissue attachment due to progression of periodontitis. RE-ATTACHMENT: Regeneration of a fibrous attachment to a root surface surgically or mechanically deprived of its periodontal ligament tissue.

15. Root Bio-modification 15 Root bio-modification is a periodontal regenerative procedure which involves chemical or mechanical modification of root surface.

16. Rationale : 16 Root debriment generates a smear layer which contains micro- organisms & toxins, that interfere in periodontal healing. Acid treatment causes demineralization of root planed dentin Exposes collagen fibrils of dentin matrix Help in adhesion of blood clot to root surface & favor migration of fibroblasts Thus, the use of an agent to remove this smear layer and to expose the collagen fibers is an important factor to obtain biologically acceptable tooth surfaces.

17. METHODS 1.Mechanical root modification By Scaling and Rootplaning 2. Chemical root biomodification By chemicals 3. Physical root biomodification By Lasers

18. DEFINITION Scaling is the process by which plaque and calculus are removed from both supragingival and subgingival tooth surfaces. No deliberate attempt is made to remove tooth substance along with the calculus. (Carranza 10 th edition) It is a procedure which aims at the removal of plaque and calculus from the tooth surface ( Lindhe: 5 th edition)

19. Root planing is the process by which residual embedded calculus and portions of cementum are removed from the roots to produce a smooth, hard, clean surface. (Carranza 10 th edition) Denotes a technique of instrumentation by which the ‘softened cementum’is removed and the root surface is made “hard” and “smooth”.(Lindhe 5 th edition) DEFINITION

20. OBJECTIVE Secure biologically acceptable root surfaces Facilitate oral hygiene procedures Resolves inflammation Decreases probing depth Improve or maintain attachment levels

21. Instruments used for root planning : Currettes, ultrasonic and sonic instruments Strokes SCALING : short powerful pull stroke ROOT PLANING : moderate to light pull stroke . As the surface becomes smoother and resistance diminishes, lateral pressure is progressively reduced

22. Amount of root structure removed during root planning : Evidence suggests that these toxic substances are only superficially attached to root and do not permeate it deeply ( hughes FJ 1986 ). Aggressive SRP for complete removal of all contaminated root cementum no longer a desired and meaningful clinical end-point.

23. the force applied to the instrument, the number of strokes performed with the instrument, the degree of mineralization of the superficial layers of the root cementum, the degree of sharpness of the curette or scaler at the start of the treatment gradual dulling of these instruments during their continued use. FACTORS

24. Chemical root biomodification Root biomodification: The application of biochemical agent to the root surface, directs the movement of specific modulators and triggering of variety of responses from cellular component of healing site, which could play an essential role in regeneration - ( Terranova et al 2005)

25. SMEAR LAYER Mechanical instrumentation leads to the formation of a smear layer: This layer of organic and mineralized debris consist of remnants of dental calculus, bacterial plaque and contaminated root cementum. Has been suggested to act as a physical barrier, inhibiting new attachment and acting as substrate for bacterial growth (Polson et al, Hansen et al 1987)

26. What is contact inhibition? Epithelial proliferation apically, being more rapid than that of connective tissue or bone regeneration, will continue along the root until it encounters granulation tissue and then stop, a process known as contact inhibition. Pritchard (1983), stated that “epithelium must be prevented from growing into the defect. Replacing the flap over the orifice of the defect is probably the most common cause of failure.” In effect, it allows for healing by secondary intention and stunting of epithelial downgrowth by bony exposure.

27. CLASSIFICATION The root surface biomodification agents are broadly classified into following categories Root Surface Conditioners Enamel Matrix P rotiens Platelet rich plasma Hyaluronic acid Recombinant human growth Factors

28. Most commonly used ` Citric acid Tetracycline HCl EDTA Fibronectin Less commonly used Laminin Doxycycline Minocycline Poly acrylic acid Chlorhexidine

29. CITRIC ACID It was suggested for smear layer removal by Register in 1973 and has been studied extensively . It is essential to human metabolism and is found in many foods. It has been used in the form of citrates as anticoagulants. Endogenous citric acid from the metabolic acid cycle has been associated with solubility of bone mineral during bone resorption.

30. With in vitro systems, citric acid has consistently enhanced features thought to be relevant in the regeneration of periodontal tissues: exposing collagen, inducing mesenchymal cell differentiation, extracting endotoxins and other toxic products, accelerating cementogenesis and widening dentinal tubules. It has been shown that citric acid demineralization enhances new attachment or reattachment and regeneration by the following mechanism.

31. Rationale Root Detoxification ( Aleo et al, 1974) Demineralization prior to cementogenesis (Register, 1975) Enhanced fibroblast growth and stability ( Boyko et al, 1980) Antibacterial Effect(Daly et al, 1982) Prevention of epithelial migration along the denuded roots (Polson et al 1983) Removal of smear layer (Polson et al, 1984) Exposure of root collagen and opening of dentinal tubules (Polson et al, 1984) Initial clot stabilization ( Wikesjo et al, 1991)

32. The recommended technique ( Register & Burdick , 1975) Raise a mucoperiosteal flap. Thoroughly instrument the root surface, removing calculus and underlying cementum. Apply cotton Pallets soaked in a saturated solution of citric acid (pH 1), and leave on for 2 to 5 minutes. Remove pallets , and irrigate root surface profusely with water. Replace the flap and suture. enhancement of connective tissue root attachment, hospitable surface for critical molecular and cellular events , .

33. Register and Burdick, 1975 produced cementogenesis and new attachment at pH 1, applied for 2-3 mm Garret, 1978 citric acid has no effect on unplanned root surface, produces 3- 5mm zone of demineralization on planed root surfaces Polson et al., 1984 citric acid application removed smear layer, leaving a mat like collagen surface with exposed dentinal tubules Boyko et al., 1980 this mat like surface permits cells cultured from periodontal ligament and gingival fibroblast to adhere better In-Vitro Studies

34. Animal studies: Human clinical studies: Polson and Proye, 1982 : i ) reattachment depended upon healthy connective tissue root fibres ii) fibrin collagen linkage between gingival fibers of clot and citric acid demineralized root is mediated by a plasma fibronectin mechanism Stahl and Froum,1977: i ) recurrence of some pockets ii) elongated junctional epithelium iii) Paralleloriented fiber immediately apical to junctional epithelium

35. DRAWBACKS Formation of extremely acidic environment ,results in unfavorable wound healing process Its low pH- induces cytotoxic effects when in direct contact with the PDL cells The factors influencing the citric acid on root surface include : Concentration of the acid pH Duration of application Mode of application

36. They are broad-spectrum antibiotics which are effective in controlling periodontal pathogens. They are the derivatives of the polycyclic naphthalene carboxamide . Tetracycline hydrochloride , Doxycycline hydrochloride and Minocycline's have been used as root conditioning agents to demineralize the root surface as it binds strongly to the root surface and can be released in an active form over extended period of time. Tetracycline

37. Sublethal concentrations of tetracycline reduces adherence and co-aggregation properties of a number of disease associated bacteria including, Porphyromonas gingivalis and Prevotella intermedia . It has a low pH in concentrated solution and this can act as a calcium chelator resulting in demineralization . Tetracyclines posses several unique antibacterial characteristics that may contribute to their efficacy in periodontal therapy

38. Rationale Rationale for use of Tetracyclinne Hydrochloride (VP Terranova et al 1986) Increases fibronectin binding whích stimulates fibroblast attachment and growth Smear layer removal, exposure of dentin tubules Endothelial cell growth factor binding to dentin, stimulating periodontal ligament cell proliferation / Migration Adsorbs to enamel and dentin. acts as antimicrobial local delivery system Collagenolytic enzyme inhibition preventing bone resorption

39. Root resorption was seen in many cases, but morphometric analysis showed better attachment gain than that achieved using citric acid ( Ririe CM, 1980 ). Human studies have shown that greater connective tissue attachment after tetracycline root conditioning. (Alger et al 1990, Wikesjo et al 1986 ) Aynes et al., 1991 not as effective as citric acid in producing root demineralization , removal of smear layer or establishing of new connective tissue attachment In vitro investigations by Baker et al. 2000demonstrated the ability of tetracyeline to bind to dentin and be subsequently released from the surface in a biologically active form over a period of time. This property has been refered to as substantivty .

40. Effect of citric acid and tetracycline hydrochloride on fibroblast behaviour Induced cementogenesis Collagen splicing Fibronectin fibrin-collagen binding thereby inhibiting epithelial apical migration Enhanced fibroblast chemotaxis, migration and attachment

41. Anticollagenase activity (Golub et al, 1984). Substantively antibacterial for 2 to 14 days (Baker, 1983) Enhances bone repair in extraction sockets ( Hars & Massler , 1972) Binds more fibronectin to demineralized surface, ( Terranova , 2000)

42. EDTA (Ethylene diamine Tetracetic acid) Chelating agent such as EDTA working at a neutral pH appears preferable with respect to preserving the integrity of exposed collagen fibers, early cell colonization and periodontal wound healing . It has been shown that pH that is not close to neutral, inhibit periodontal ligament fibroblasts. Thus, it is suggested that neutrally buffered EDTA will reduce the probability that the soft tissues of the periodontium will be damaged. Various concentrations of EDTA has been used in studies ranging from 12%-24%, neutral pH for 30 s to 3 min aiming at removing smear layer and widening dentin tubules without damaging biological structures

43. ACTIONS Chealating agent Functions by forming a calcium chelate solution with calcium ions. Softens Root surface. Removes smear layer. Effects partial demineralization to a depth of 20-30m in 5 minutes

44. Raise flap Remove granulation tissue, tissue tags and root deposits Control bleeding Remove smear layer with citric acid (pH 1) or EDTA (pH 6.4) for 15 seconds Rinse with saline Apply gel to cover entire root surface Suture the flaps Place the pack STEPS

45. In vivo study ( Polon et al-1997) – Cases phosphoric acid/ EDTA for 3 minutes Controls untreated Teeth extracted 2X 3mm of attachment apparatus removed > teeth reimplanted - After 14 days teeth removed and seen under SEM Control Smear layer present None showed complete colonization by cells or tissues Phosphoric acid Filled almost completely with fibroblast like cells Little sign of migrating or stationary cells EDTA Filled almost completely with fibroblast like cells

46. Vitality of periodontal tissues following application of citric acid, phosphoric acid and neutrally buffered EDTA ( Blomlot et al., 1999): -Soft tissues bathed in various preparations for 20 seconds and for 3 minutes - Windows prepared to remove periodontal ligament underlying tooth surfaces treated with various materials -Tissues incubated> cellular activity checked -Cellular activity was found in the control (saline) and EDTA groups, not in phosphoric and citric acid groups

47. Enhanced healing with EDTA compared to citric acid ( Blomiof et al., 2000): Patients with no oral hygiene 8 weeks after periodontal surgery 10 % less failure recession, pocket formation 10 % to 15% more histologic attachment 20 % less length of junctional epithelium and 20% more connective tissue

48. FIBRONECTIN It is a high molecular weight glycoprotein that is found in the extracellular tissue and is the main component that holds the clot together. I t also performs several functions that fosters the reattachment of periodontal tissues to the root surface in the surgical treatment of periodontal disease. Seelich and Redl (1979) fibronectin holds the clot together. Boyko et al. (1980) promote cell adhesion to collagen and scaled root surfaces Kleinmann et al. (1981) > chemotactic effect on fibroblast and mesenchymal cells Caffesse et al. (1987) enhances effect of demineralization with regard to new attactment and cell proliferation from PDL

49. It facilitates fibrin formation and its linkage to the root surface which is an initial stage after demineralization and prior to new attachment. It stimulates the coronal growth of cells from the periodontal ligament which are responsible for new attachment and favors the growth and attachment of fibroblasts over epithelial cells to the root surface. Speeds the linkage process by being chemo-attractive for fibroblasts and stabilizing the clot between the exposed root surface collagen and new fibers within the tissue Promotes mesenchymal cell adhesion, Chemotaxis and G rowth Rationale

50. LAMININ The most abundant components of basement membranes are the laminins and type IV collagens . While collagen has some adhesion promoting activity, laminin has been demonstrated to have potent actions on cells: stimulating cell adhesion, growth, differentiation, and migration. It has been shown that laminin promotes gingival epithelial chemotaxis and in addition, movement of gingival fibroblasts .

51. The affinity of laminin and fibronectin are not same towards mineralized surface. A mineralized surface attract laminin which favours epithelial proliferation whereas a demineralized surface attract fibronectin and favour fibroblast proliferation

52. Doxycycline belongs to the tetracycline group of drugs . This an effective antimicrobial agent against periodontal pathogens. Along with this, it has anti enzymatic properties. Topical application of doxycycline has shown a long lasting substantivity on periodontally diseased root surfaces. It has been demonstrated that the antibacterial effect of doxycycline persists on the conditioned root surface upto 14 days. DOXYCYCLIN

53. Being a weak acid polyacrylic acid has been used as root surface conditioning agent. Its acid etching effect removes smear layer from the root surface making it more suitable for healing . A study compared periodontal healing after application of polyacrylic acid for 20 seconds and citric acid application for 3 minutes on root surface - Wiland et al -1990 Results: demonstrated a greater connective tissue adhesion to root surface in case of polyacrylic acid treated teeth as compared to citric acid treated teeth. Because a little clinical data is available regarding effect of polyacrylic acid on root surface and its biological effects, more clinical research is required to authenticate its clinical use. POLYACRYLIC ACID

54. Bogle G et al studied the effect of post operative use of chlorhexidine on regeneration of bifurcation defects in dogs. Chlorhexidine applied to the root surface during surgical treatment of bifurcation defects in dogs resulted in an increase in bone height but not in the level of connective tissue attachment. CHLORHEXIDINE

55. Moss M, Kruger and Reynolds DC-1992 observed that the use of chondroitin sulfate in extraction sites accelerated the repair but did not affect the ultimate quantity or quality of bone produced CHONDROTIN SULPHATE

56. It acts as a bactericidal and cleaning agent. It degrades endotoxins by hydrolysis. Lasho DJ et al 2000 in a study comparing citric acid, EDTA and sodium hypochlorite observed that surfaces treated with sodium hypochlorite were uneven with debris. When compared to the control group, however, the surface, showed a better appearance by exposing dentinal tubules and less debris. SODIUM HYPOCHLORITE

57. Morris and Singh 2000; reported clinical responses in 44 cases treated by interproximal denudation and root surface conditioning with a formalin solution. Radiographic evaluations indicated bone growth in 45 of 65 defects and clinical attachment gain of 2.7mm. Since there were no controls, they did not determine how much of the response was due to the surgical approach and how much resulted from the formalin application FORMALIN

58. ENZYMES Willey and Steinberg -2003 evaluated the effect of topical applications of Hyaluronidase, Elastase and collagenase to citric acid - demineralized root surface. All of the enzyme treatments appeared to expose more collagen than demineralization one. Collagenase application appeared to clear all ground substance from the collagen fibrils. The other enzymes appeared to clear partially the inter-collagenous ground substance

59. Enamel Matrix Proteins. Mainly Amelogenin, are secreted by HERS during tooth development and induce acellular cementum Based on these observations, they are believed to favor periodontal regeneration. ( Hammarstrom 1997 )

60. The application of Enamel Matrix Protein ( amelogenins ) may promote periodontal regeneration as it mimics events that take place during the development of periodontal tissues In a clinical study long term effect of Enamel Matrix Protein treatment as an adjunct to modified Widman flap surgery vs modified Widman flap plus a placebo was assessed . The results in the EMP group were better, as shown by a gain in the clinical attachment level, probing depth reduction and restoration of bone radiographically

61. It is a resorbable , implantable material that consists of enamel matrix proteins extracted from developing embryonic enamel of porcine origin supplied in sterile form. Emdogain contains a protein preparation that mimics the matrix proteins that induce cementogenesis. During root development, the Hertwig’s epithelial sheath deposits enamel matrix proteins on the newly formed root dentin surface. These proteins stimulate the differentiation of surrounding mesenchymal cells into cementoblasts , which form acellular cementum. EMDOGAIN

62. The major constituents arc amelogenins . Other proteins identified include ameloblastin and enamelin . It uses propylene glycol alginate (PGA) as a carrier. EMD is absorbed into the hydroxyapatite and collagen fibers of the root surface, where it induces cementum formation followed by periodontal regeneration. Emdogain has two presentation forms: One is in liquid and powder form, in 2 separate bottles containing the vehicle and the protein powder and the other is in the form of gel in syringe. The material is stored in the refrigerator, at 2-8°C. It should be used in no more than 2 hours from opening, because it gelifies and hardens

63. The technique,( Acc to Mellonig ) Raise a flap for regenerative purposes Degranulation and exposing the bone . Completely control bleeding within the defect. Demineralize the root surface with citric acid pH 1, or preferably with 24% (EDTA Biora ) pH 6.7 for 15 seconds,facilitates adherence of the Emdogain .

64. Rinse the wound with saline and apply the gel to fully cover the exposed root surface . Avoid contamination with blood or saliva . Close the wound with sutures. Perfect abutment of the flaps is necessary , if necessary scalloping and/or osteoplasty . 7. Systemic antibiotic coverage for 10 to 21 day recommended . (Doxycycline, 100 mg daily)

65. Histologic study : 10 defects in 8 patients, ( Yukna and Mellonig ) Ev i denc e s o f re g e n er a t i on (new ce m e nt u m , new b o n e, an d n e w periodontal ligament)in 3 specimens. N e w attac h m e n t (co n n e cti v e tissue attac h me n t / a d h es i o n o n l y ) i n 3 specimens , No evidence of root resorption or ankylosis was found.

66. Heijl et al have compared the use of enamel matrix derivatives with a placebo in 33 patients with 34 paired test and control sites, mostly one and two wall defects, followed for 3 years. They found a statistically significant radiographic bone gain of 2.6 mm.

67. Abbas et al - 2003 describes the clinical procedure and outcome of surgical treatment of gingival recessions with the adjunctive use of Emdogain gel, results in predictable root coverage and gain of clinical attachment while maintaining shallow pockets . Cheng et al -2007 had a review of coronally positioned flap + enamel matrix derivative (EMD ) for the treatment of Miller class I and II gingival recession which shows statistical significant root coverage. .

68. Platelets are important component of blood coagulation cascade. Major components of platelet structure are secretory granules (primary, secondary and tertiary granules), which contain growth factors, coagulation proteins, adhesion molecules, cell activating molecules, cytokines. The concept behind PRP application for periodontal regeneration is to obtain high density platelet concentrate from patient's own blood and then applying this concentrate in the area of periodontal wound healing where regeneration is desired. PLATELET CONCENTRATES

69. Platelet derived growth factor (PDGF) is a major mitogen for fibroblasts, smooth muscle cells, and other cells Platelets synthesize a mixture of the three possible PDGF Isoforms (70% AB, 20% BB, 10% AA) . It has-been-shown that PBEFAB is apotent stimulator of DNA synthesis-in-fibroblasts.

70. HA is an essential component of the periodontal ligament matrix and plays various important roles in cell adhesion , migration and differentiation mediated by the various. HA binding proteins and cell-surface receptors such as CD44. HA has been studied as a metabolite or diagnostic marker of inflammation in the gingival crevicular fluid (GCF) as well as a significant factor in growth, development and repair of tissues. Hyaluronan has numerous roles in the initial infammatory stages such as the provision of a structural framework via the interaction of Hyaluronan with the fibrin clot, which modulates host's inflammatory and extracellular matrix cell infiltration into the inflamed site Hyaluronic Acid (HA)

71. Hakansson , et al. 1998 suggested role of Hyaluronan , in migration and adherence of polymorphonuclear leukocytes and macrophages at the inflamed site and the phagocytosis and killing of invading microbes. HA accelerates the bone regeneration by means of chemotaxis, proliferation and successive differentiation of mesenchymal cells . HA shares bone induction characteristics with osteogenic substances such as bone morphogenetic protein contains high molecular weight fractions of HA in a gel formulation with 0.2% concentration for its effect in the treatment of plaque-induced gingiviti's as an adjunct to SRP

72. GROWTH FACTORS Biological mediators that regulate connective tissue cell migration, proliferation, synthesis of proteins and other components ofECM. Those that may be of value in periodontal therapy are PDGF- 1, IGF TGF-beta and B-FGF. etc

73. These molecules are released by platelets, endothelium, fibroblasts, smooth muscle cells, and macrophages in inflamed tissues and healing wounds. synthesized by an originating cell, travel to its target receptor, interact with the target receptor or binding protein, and activate second messengers or terminal effectors. MECHANISM OF ACTION

74. PLATELET DERIVED GROWTH FACTOR Naturally occurring protein , abundant in bone matrix. It is released locally during clotting by blood platelets at the site of soft and hard tissue injury, cascade of events ,wound healing response . ACTIONS P otent chemotactic and mitogenic - PDL fibroblasts, cementoblasts , osteoblasts R educe the inhibitory effects of lipopolysaccharide (LPS) on gingival fibroblast proliferation.( Bartold PM, Narayanan AS1992).

75. In cultures of osteoblast-like cells, alkaline phosphatase activity and osteocalcin are down-regulated . In vivo, enhanced demineralized bone matrix-induced cartilage and bone formation.( Howes R,)

76. Clinical trials in humans- only high doses of these factors gave rise to a statistically significant increase in alveolar bone formation . Platelet- derived growth factor in combination with bone allografts to treat Class II furcations and interproximal intrabony defects, regeneration of new alveolar bone, cementum, and periodontal ligament (Camelo M, ).

77. INSULIN LIKE GROWTH FACTOR Family of single-chain serum proteins -49% homologous with proinsulin . S y nt h e s iz e d – b y mu l t i p l e tissu e s i n cluding l i ve r , smo o th musc l e and placenta , and carr i ed i n plasma a s a com p lex w i t h sp e cific bin d i ng pr o tei n s. ( N . Matsuda,1992 )

78. ACTIONS Chemotactic for PDL derived cells. PLF mitogenesis and protein synthesis (in vitro). Stimulates bone formation (cellular proliferation, differentiation) Type I collagen biosynthesis . Studies Application to rat tooth root surfaces promoted cementogenesis within 8 days after reimplantation molars.(Cho MI1991)

79. Root Conditioning by Lasers

80. Recently , lasers have been recommended as an alternative or adjunctive therapy in the control and treatment of periodontally diseased root surface. Lasers are capable of sterilizing the diseased root surface and thus, ultimately promoting cell reattachment. An effect of lasers on the root surface has been derived from morphologic studies of lased enamel and dentin. Lased tooth surfaces characteristically show crater formation with drops of melted dental hard tissues (Hess and Myers 1990 ). Smith et al 1995, Koichi et al 1993 observed properties of lasers which can sterilize, vaporize and ablate hard surface.

81. This offers an effective means of removing adsorbed endotoxin, calculus, plaque and other root surface contaminants. (Schwarz et al 2001) Commercially available laser systems: The number of commercially available laser systems is limited to some infrared laser namely 1. Carbon dioxide laser 2 . Nd: YAG ( Neodynium;Yttrium;aluminium and garnet) lasers 3. Er : YAG ( Erbium:Yitrium , aluminium and garnet) lasers.

82. Er : YAG Laser is also highly absorbed by hydroxyapatite . Therefore, the Er:YAG laser can ablate hard tissues containing some water, more effectively and causes less thermal damage to the adjacent tissues . (Schwarz et al 2001) Schwarz et al 2006 used Er:YAG Laser in patients with moderate periodontitis and compares to SRP which has Significant decrease in BOP, PD, was seen in laser group (3& 6 months ) Er:YAG Laser can be suitable alternative to scaling and root planing .

83. Laser application on root surface has a significant effect on fibroblast attachment . In an in vitro study, the effect of Nd:YAG laser concluded that laser exposure denatures the surface protein which inhibits fibroblast attachment. Thomas et al - 1994 Dilzis et al - 2010 has used ND:YAG laser negatively affected root coverage outcomein Sub epithelialized Coronally advanced flap in Gingival recesion patients The SEM and histologic findings demonstrated the feasibility of ablating pocket epithelium with an Nd:YAG laser irradiation Furthermore and appeared to have an impact on the degree of laser-mediated epithelial ablation Chan et al -2014

84. CO2 lasers are capable of ablating calcified tissues effectively . However, they have the same limitations of thermal side effects such as cracking or charring at the target site and pulpal damage like Nd:YAG laser . Researchers have suggested their use for scaling, root planing and root conditioning . Risk of rise in intra-pulpal and root surface temperature appear common with use of lasers . Melting and also loss of cementum appear more with use of this laser. CO2 LASER

85. A study concluded that the usage of the C02 and Er:YAG laser at the determined power settings can treat dentin hypersensitivity and reduce its symptoms significantly. However, the Er:YAG laser has a greater effect on tubular occlusion with less thermal change; thus it may act as a useful conditioning tool under such conditions. An in vivo study examined morphologic alterations in the periodontal pocket epithelium with presence or absence of clinical inflammation following the use of the Neodymium : Yttrium-Aluminum-Garnet ( Nd:YAG ) laser irradiation - Belal et al

86. Common and McFall (1983) compared treatment of experimentally-induced human recession using laterally positioned pedicle flap surgery with and without citric acid conditioning. Citric acid (pH 1) was rubbed onto the prepared root surface for 2 minutes. Control teeth exhibited a long junctional epithelium with no cementogenesis . The citric acid-treated pedicles had a connective tissue attachment to new cementum and, at 1 month postsurgery , did not separate from the teeth as easily as the controls . Efficacy of root biomodifying agents in periodontal surgery

87. Caffesse et al. (1988) treated two sextants in each of 29 subjects with modified Widman flap surgery while another two sextants received the same treatment supplemented with citric acid and fibronectin application. While citric acid/fibronectin application improved probing depth and probing attachment levels to a statistically significant degree, the difference was clinically insignificant (a matter of 0.2 to 0.3 mm). Smith et al. (1986) used a split mouth design to study the effects of citric acid on new attachment during surgery. Experimental sites were treated with citric acid pH 1 for 3 minutes. Clinical attachment levels were evaluated at 3 and 6 months after surgery. There was no difference between acid treated and non-acid treated teeth

88. AAP Regeneration Workshop on Periodontal Soft Tissue Root Coverage Procedures concluded that the use of root modifiers or other surface biomodification procedures did not provide superior gains in clinical outcomes, either short or long term, than those expected for procedures performed without such agents. Karam et al. conducted a systematic review on root surface modifiers and subepithelial connective tissue graft for treatment of gingival recessions and concluded that based on the present clinical data, the use of root surface modifiers to improve clinical outcomes in gingival recessions treated with SCTG is not justified.

89. Angelo Mariotti in a systematic review on efficacy chemical root surface biomodifiers in the treatment of periodontal disease concluded that chemical modifiers like EDTA, citric acid or tetracycline provides no benefit clinical significance to regeneration in patients with chronic periodontitis

90. CONCLUSION Root conditioning, now also called Chemically guided tissue regeneration is recommended for infrabony defects, as an implant additive and as a primary treatment for class ll furcations with or without bone implants and also with guided tissue regeneration and for cosmetic gingival reconstruction . Citric acid root conditioning although not yet fully supported by research on humans does provide significant benefits that cannot be achieved by scaling and root planing alone . Both citric acid and tetracycline provide a surface substrate for future use of protein-modifiers-

91. REFERENCES Periodontal regeneration: Current status and directions Alan M. Polson Regeneration of the periodontal attachment in humans - Mick R. Dagoo Periodontics Grant, Stern, Listgarten , 6th ed . Atlas of cosmetic and reconstructive periodontal surgery Edward S. Cohen Workshop on Contemporary science in clinical periodontics- Annals of Periodontology 2003

92. Non surgical periodontal therapy - Perio 2000, Vol. 36, 2004 Caranza's Clinical Periodontalogy Newman, Takei, Klokkevold , Caranza , 10th ed . Leite FR, Sampaio JE, Zandim DL, Dantas AA, Leite ER, et al. (2010) Influence of root surface conditioning with acid and chelating agents on clot stabilization. Quintessence Int 41: 341-9 . Register AA (1978) Induced reattachment in periodontal endodontic lesion by root demineralization in situ. Oral Surg Oral Med Oral Pathol 45: 774-83 .

93. Hanes PJ, O'brien NJ, Garnik JJ (1991) A morphological comparison of radicular dentin following root planing and treatment with citric acid or tetracycline HCI. J Ciin Periodontal 18: 660-8. Haghighati F, Arefi V (2002) A comparative study on root surface demineralization using citric acid and tetracycline in vitro: a scanning electron microscopy study. Acta Medica Iranica 40: 247-55 . Periobasics : A text book of Periodontics and Implantology- Second edition

94. Felix Krause, Gerhard Schmalz , Kyung Jin Park, Jana Schmidt, Dirk Ziebolz ,  Hartmut Schneider, Rainer Haak , Evaluation of calculus imaging on root surfaces by spectral-domain optical coherence tomography, Photodiagnosis and Photodynamic Therapy, 10.1016/j.pdpdt.2019.01.014, (2019 ). Coldiron NB, Yukna RA, Weir J, Caudill RF. A quantitative study of cementum removal with hand curettes. J Periodontol . 1990 May;61(5):293-9. doi : 10.1902/jop.1990.61.5.293. Bosshardt DD, Selvig KA. Dental cementum: the dynamic tissue covering of the root. Periodontol 2000. 1997 Feb;13:41-75. doi : 10.1111/j.1600-0757.1997.tb00095.x.

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