Gingival Retraction

Fixed Partial Denture - Gingival Retraction

1. Good Morning

2. Gingival Retraction in Fixed Partial Dentures Presented by : Dr Harshil Modi (3 rd Year Post Graduate ) Guided By : Dr Darshana Shah Dr. Chirag Chauhan Dr. Paras Doshi Beyond the finish lines !

3. Index Definition Introduction Criteria for selection of retraction Cords Mechanical method rubber dam cotton twills with ZnoE cement copper band impression temporary acrylic resin copings

4. Chemical Method Chemical Agents Classification Of Retractin Cords & Indications Types Of Retraction Methods used Electro surgery History Mechanism of Action Types of current Advantages and disadvantages Technique

5. Recent Advances in Gingival Retraction material Muracel retraction strips Magic foam Expaysyl retraction paste Summary References

6. Definition Gingival Retraction /Gingival Displacement: The deflection of the marginal gingiva away from a tooth - GPT 9

7. GINGIVA

8. Fluids of Oral Cavity Why are we talking about these 4 fluids !? Sign of warning in examination when examiner asks you wether GCF is a Transudate or an Exudate ?

9. Introduction One of the important factor which contribute to the success of cast restorations is marginal integrity. Inadequate marginal fit leads to:- -dissolution of luting agent. -seepage and cervical caries. -periodontal disease. Though supra-gingival finish lines are preferred because of their easy cleaning, finishing, impression making and evaluation advantages, at times we have to make sub-gingival finish lines.

10. Introduction To achieve good marginal fit and esthetics the gingival finish line should be recorded in the impression. The inability of most final impression materials to adequately displace soft tissues, fluid or debris mandates adequate gingival displacement. Hydrophobic Vs Hydrophillic !

11. Aims Of Gingival Retraction To reflect the gingiva and produce enlarged gingival sulcus both in vertical and lateral directions. It also facilitates to refine the finish lines prior to impression making especially in anterior metal ceramic restorations. To obtain an adequate access to the prepared tooth to expose all necessary surfaces, both prepared and not prepared. To control seepage of gingival fluid.

12. Classification of gingival retraction methods

13. Mechanical Methods (Physical Compression) Copper Band Impressions Means of carrying the impression material and a mechanism for gingival retraction. Technique Selection of copper band. One surface of band may be perforated. Cervical end of the band may be trimmed in accordance with the finish line. The band is filled with soft wax and seated on the tooth. The wax is chilled and impression is removed. The impression indicates over extension of the band. Adjustments if required may be made and second trial impression is made.

14. Mechanical Methods

15. Mechanical Methods The wax is melted and modelling compound is introduced. Seat the band securely into its position. Pressure is applied on the compound directly. Chill the impression. A towel clamp may be used to remove the impression. A NEW METHOD ADVOCATES USE OF ELASTOMERIC MATERIALS AS WELL Reference : Hovestad JF. Fixed Dental Prosthesis. St. Louis : Mosby , 1924: 34-36

16. Mechanical Methods Can we evaluate the Disadvantages by ourselves ? Hints : Ruel , J., Schuessler , P.J., Malament , K. and Mori, D., 1980. Effect of retraction procedures on the periodontium in humans.  Journal of Prosthetic Dentistry ,  44 (5), pp.508-515.

17. Mechanical Methods 2. Rubber Dam Heavy and extra heavy rubber dams were used. Retraction is done by rubber dam or clamps (No. 212 cervical retainer). Produced retraction by compression . Advantages control of seepage and hemorrhage. ease of application. Disadvantages full arch models cannot be made. severe cervical extension preparations. Cannot be used with polyvinylsiloxane impression materials .

18. Mechanical Methods Why Can VPS Impression material not be used along with this method ? Basset, R.W., Ingraham , R. and Koser , J.R., 1964.  An atlas of cast gold procedures  (Vol. 2). Department of Operative Dentistry, University of Southern California, School of Dentistry.

19. Mechanical Methods 3. Cotton Twills with ZnOe Cement Employs gentle pressure over a period of time. ZnoE mixed into creamy consistency. Prevents sticking of pack to the instruments and gives ease in handling. Should reflect the tissue laterally. Pack held in place with fast setting Znoe cement.

20. Chemico – Mechanical ( Retraction Cord ) Gingival retraction using chemically impregnated retraction cord is a mechanico - chemical method of displacement . Mechanical aspect involves placement of the cord into the gingival sulcus . Chemical aspect involves effect of the chemicals/medicaments in the cord on the gingival sulcus .

21. Chemico – Mechanical ( Retraction Cord ) Benson, B.W., Bomberg , T.J., Hatch, R.A. and Hoffman, W., 1986. Tissue displacement methods in fixed prosthodontics .  Journal of Prosthetic Dentistry ,  55 (2), pp.175-181.

22. Trade Name: Prevest DenPro Haemostal Liquid What chemical agent do we use in our department frequently ?

23. Chemico – Mechanical ( Retraction Cord ) Mechanism of Action Vasoconstrictors – Physiologically restrict the blood supply to the area by decreasing the size of the blood capillaries, tissue fluid seepage and consequently size of the free gingiva . Ex: epinephrine and norepinephrine B) Biologic fluid coagulants: Coagulate blood and tissue fluids locally, creating surface layer that is efficient sealant against blood and crevicular fluid seepage. Ex: 100% alum, 15-25% aluminium -chloride, 10% aluminium potassium sulphate and 15-25% tannic acid. C) Surface layer tissue coagulants – coagulates surface layer and free gingival epithelium as well as seeped fluids, this creating temporarily impermeable film for underlying fluids. Disadvantage: Ulceration, local necrosis, and change in the dimension and location of the free gingiva . Ex: 8% zinc chloride and silver nitrate.

24. Chemico – Mechanical ( Retraction Cord ) Review of Literature ( Agents no longer used ) 8% Racemic Epinephrine ( used and popuar only till late 1980’s) 45% Negatol solution(45% condensation product of meta cresol sulfonic acid and formaldehyde) Caustic acid – sulfonic acid , trichloracetic acid. Nasal and ophthalmic decongestants- Oxymetazoline hydrochloride 0.05% Tetrahydrozoline hydrochloride 0.05% Phenylephrine hydrochloride 0.25% Combinations of chemicals Cocaine 10% with 0.1% epinephrine Zinc chloride with 8% epinephrine

25. Chemico – Mechanical ( Retraction Cord ) 8% Racemic Epinephrine ( used and popuar only till late 1980’s) ™Is 1 Of 2 Hormones Of Sympathetic Part Of AUTONOMIC NERVOUS SYSTEM ™Able & Crawford (1897) - Separated Epinephrine From Medullary Portion Of Adrenal Gland ™Acts As A Vasocostrictor Primary Site Of Action On Walls Of Small Arterioles. LOCAL EFFECT Produces Hemostasis Local Vasoconstriction Transitory Gingival Shrinkage There Is No Benefit In Increasing The Strength Of Epinephrine Impregnated Cord Beyond 4% For Hemorrhage Control (Timberlake)

26. Chemico – Mechanical ( Retraction Cord ) FACTORS AFFECTING AMOUNT OF EPINEPHRINE ABSORPTION Degree Of Exposure Of Vascular Bed ( Gogerty et al) Time Of Contact ( Woychesin ) Amount Of Medication In Cord (Forsyth et al) Amount Of Laceration Of Gingival Tissue No Of Teeth Prepared Epinephrine In L.A. ( If Used) Endogenous Secretions Medications Taken ( If Any)

27. Chemico – Mechanical ( Retraction Cord ) EPINEPHRINE SYNDROME 1)tachycardia 2) Increased Blood Pressure 3) Nervousness 4) Anxiety 5) Increased Respiration 6) Post Operative Depression These Effects May Appear After Cord Has Been In Place For A Few Mins /Some Time After Removal Of Cord

28. Article Criticizing use of Racemic Epinephrine Banu , S. and Jain, A.R., 2018. Evaluation of variation in the systemic blood pressure among Indian population after placement of retraction cord with and without local anesthesia containing epinephrine.  Drug Invention Today ,  10 (1).

29. Viva Voice Which Chemical Agent ( commonly ) do we use in Gingival Retraction ? ( in our department ) What is the concentration of the chemical agent we use ? What is the time that should be kept in ? What is Monsels Solution ( 25 % Fe2 so4 )

30. Chemico – Mechanical ( Retraction Cord ) A gingival retraction cord is the one which is having a tapered diameter throughout its length and having a length sufficient to enable the cord to be wrapped several times about a tooth. In use, the cord, starting with its smaller end, is spirally wrapped and packed about a tooth between the tooth and surrounding gingival tissue to form a flared gingival crevice. Patent number : 4465462 Filing date : Apr 27, 1983 Issue date : Aug 14, 1984 Inventor : Verne E. Ticknor Current U.S. Classification 433/136 ; 433/215 ; 132/93 ; 604/1 International Classification A61C 514

31. Chemico – Mechanical ( Retraction Cord ) Desirable qualities of a cord ( Donovan, Gandara , Nemetz ) Dark Color To Maximize Contrast With Tissues,Tooth & Cor d Absorbent To Allow For Uptake Of Wet Medicament Available In Different Diameters To Accommodate Varying Morphologies Of Gingival Sulcus Cord May Be Saturated With Solution Prior To Insertion Placed Dry, Solution Applied Previously Impregnated By Manufacturer

32. Chemico – Mechanical ( Retraction Cord ) Classification of Retraction Cords Depending on the configuration Braided Twisted Knitted b. Depending on surface finish waxed unwaxed c. Depending on the chemical treatment plain impregnated

33. Chemico – Mechanical ( Retraction Cord ) Classification of Retraction Cords d. Depending on number strands single double-string e. Depending on the thickness (color coded) black 000 yellow 00 purple blue 1 green 2 red 3

34. Knitted gingival retraction cord Dan E. Fischer . Because of the presence of numerous interlocking loops, the knitted retraction cord is longitudinally elastic , thereby avoiding the tendency to become dislodged once packed as additional portions of the cord are packed around the margin of a tooth. The knitted retraction cord is also transversely resilient , thereby tending to better conform to the gingival sulcus . Patent number : 4522593 Filing date : Jul 7, 1983 Issue date : Jun 11, 1985 Inventor : Dan E. Fischer Current U.S. Classification 433/136 International Classification A61C 514

35. Braided gingival retraction cord   Don D. Porteous A gingival tissue retraction cord is provided which comprises a suitably dimensioned, moderately firm, flexible, multistrand , braided, absorbent cord impregnated with an effective amount of gingival tissue retraction material. . Patent number : 4321038 Filing date : Jul 18, 1980 Issue date : Mar 23, 1982 Inventor : Don D. Porteous Assignee : Van R Dental Products, Inc. Primary Examiner : John J. Wilson Current U.S. Classification 433/136 ; 128/335.5 International Classification A61C 514

36. Teflon-coated intraoral tissue retraction cord   Jeffrey O. Earle The retraction cord (or tape) includes a thermoplastic material such as polytetrafluoroethylene (i.e. PTFE or Teflon ) so that the cord is resistant to shredding, tearing, and sticking to dental restorative and impression taking materials . Additionally, chemical treatment of the cord may be avoided so as to reduce the risk of harmful side effects in chemically sensitive patients.

37. Chemico – Mechanical ( Retraction Cord ) Indications of #000 Anterior teeth Double packing Substitute for black silk suture as lower cord in the "two-cord" technique Indications of #00 Preparing and cementing veneers Restorative procedures dealing with thin, friable tissues

38. Chemico – Mechanical ( Retraction Cord ) Indications of #0 Lower anteriors When luting near gingival and subgingival veneers Class III, IV and V restorations Second cord for "two-cord" technique Indications of #1 Tissue control and/or displacement when soaked in coagulative hemostatic solution prior to and/or after crown preparations Protective "pre-preparation" cord on anteriors

39. Chemico – Mechanical ( Retraction Cord ) Indications of #2 Upper cord for "two-cord" technique Tissue control and/or displacement when soaked in coagulative hemostatic solution prior to and/or after crown preparations Protective "pre-preparation" cord on anteriors Indications of #3 Areas that have fairly thick gingival tissues where a significant amount of force is required Upper cord for those desiring the "two-cord" technique

40. Gingival Biotype Does Gingival Biotype effect the type of retraction cord used ?

41. Gingival Biotype

42. Chemico – Mechanical ( Retraction Cord ) ARMAMENTARIUM Evacuator (saliva ejector, svedopter ) 2) Scissors 3) Cotton pliers 4) Mouth mirror 5) Explorer 6) Fischer Ultra Packer (small) 7) DE plastic filling instrument IPPA 8) Cotton rolls 9) Retraction cord 10) Hemodent liquid 11) Dappen dish 12) 2 x 2 gauze sponges

43. Chemico – Mechanical ( Retraction Cord ) Requirements of Instrument used for placing cord Double Ended With Adequate Blade Angle & Offset To Allow All Areas Around A Full Crown Preparation To Be Packed Blade Should Be Long Enough To Reach Deep Finish Lines Small Enough In All Dimensions To Avoid Gingival Injury During Cord Placement End Of Blade Should Be Flat No Sharp Corners Should Be Present

44. Chemico – Mechanical ( Retraction Cord ) 45 degrees to handle . most popular packers; heads at 45 degrees to the handle with three packing sides. Circular packing of the prep is completed without the need to flip the instrument end for end. Use the small packer on lower anteriors and upper lateral incisors. 90 degrees & parallel to handle . Same size and three sided heads as our 45 degrees packers, except one of the heads is in line with the shank and the other is at a right angle to the shank.

45. An Alternative…. What would you do if you don’t have any cord packers ?

46. Chemico – Mechanical ( Retraction Cord ) Techniques of gingival retraction: Single cord technique. Double cord technique. Infusion technique of gingival displacement. Every other tooth technique.

47. Chemico – Mechanical ( Retraction Cord )

48. Chemico – Mechanical ( Retraction Cord )

49. Chemico – Mechanical ( Retraction Cord )

50. Chemico – Mechanical ( Retraction Cord ) Double cord technique: Indication: When making impression of multiple prepared teeth and when making impression when tissue health is compromised. Procedure: Small diameter cord is placed in sulcus . This cord is left in the sulcus during impression making. Second cord is soaked hemostatic agent of choice is placed in the sulcus above small diameter cord. After waiting 8-10 minutes, the larger cord is removed.

51. Video for Double Cord Technique

52. Chemico – Mechanical ( Retraction Cord ) Infusion technique: It is indicated to control the haemorrhage . Infuser is used with a burnishing motion in the sulcus and carried circumferentially 360° around the sulcus . Haemostasis is verified, a knitted retraction cord is soaked in ferric sulphate and packed into the sulcus . The cord is removed after 1-3 minutes.

53. Chemico – Mechanical ( Retraction Cord )

54. Chemico – Mechanical ( Retraction Cord ) A study on new series of knitted and twined gingival cord impregnated with 8% epinephrine and 25% aluminium sulphate and concluded that knitted gingival cords were better than twined cords and cords containing epinephrine performed clinically no better than aluminium sulphate cords. Jokstad , A., 1999. Clinical trial of gingival retraction cords.  Journal of Prosthetic Dentistry ,  81 (3), pp.258-261.

55. Chemico – Mechanical ( Retraction Cord ) Ferenc Csempesz et al in 2003 conducted a study to determine the optimum soaking time for 3 retraction cords of different thickness to ensure adequate uptake of the hemostatic solution and concluded that 20 mins of soaking time was necessary for saturation of the cords before use. In addition to soaking time, the saturation of the cord with solution largely depends on wetting of the cords. Csempesz , F., Vág , J. and Fazekas , Á., 2003. In vitro kinetic study of absorbency of retraction cords.  Journal of Prosthetic Dentistry ,  89 (1), pp.45-49.

56. Rotary Gingival Curretage “ Gingitage ” or “ Denttage ” Troughing technique Purpose is limited removal of epithelial tissue while a chamfer finish line is being created. Amsterdam gave the concept,further developed by Hansing and Ingraham .

57. Rotary Gingival Curretage Criteria for rotary curettage 1.Must be done on healthy and inflammation free tissue to prevent tissue shrinkage that occurs when diseased tissue heals. 2.Absence of bleeding on probing. 3.Sulcus depth less than 3.0 mm. 4.Presence of adequate keratinized gingiva .

58. Rotary Gingival Curretage Technique Shoulder finish line preparation at gingival crest using flat end tapered diamond. Then with a torpedo diamond finish line is extended apically,1/2 to 2/3 the depth of the sulcus . Place aluminium chloride impregnated retraction cord to control hemorrhage. Remove the cord after 4-8 minutes and make impression.

59. Rotary Gingival Curretage

60. Rotary Gingival Curretage Violation with Basic Biological Prinicple of tooth preparation ?

61. Electro Surgery / Electro Cautery Often “ electrocautery ” is used to describe electrosurgery . This is incorrect. Electrocautery refers to direct current (electrons flowing in one direction) whereas electrosurgery uses alternating current. During electrocautery , current does not enter the patient’s body. Only the heated wire comes in contact with tissue. In electrosurgery , the patient is included in the circuit and current enters the patient’s body.

62. An Electro Cautery Unit

63. Electro Surgery / Electro Cautery Fun Fact History Schillinburg stated that the use of heat as surgical tool was known to Egyptians about 3000BC. Experiments of d’Arsonvol (1891) demonstrated that electricity at high frequency will pass through a body without producing a shock (pain or muscle spasm), instead producing an increase in the internal temperature of the tissue. This discovery was used as the basis for eventual development of electrosurgery .

64. Electro Surgery / Electro Cautery Mechanism Of Action Controlled tissue destruction. Current flows through a small cutting electrode. Producing high current density and rapid temperature rise . Cells directly adjacent to the electrode are destroyed due to this temperature increase.

65. Electro Surgery / Electro Cautery Tissue Considerations Keep electrode in motion. Appropriate current setting. Larger the electrode ,greater the current required. 5-10 seconds between applications. Tissue must be moist. Electrode must remain free of tissue fragments. Electrode must not touch any metallic restorations.

66. Electro Surgery / Electro Cautery Advantages Clear operating area without or no bleeding. Healing by primary intension. Lack of pressure to incise tissue. Electroplaining of tissue. less tissue loss after healing

67. Electro Surgery / Electro Cautery Disadvantages Unpleasant odour . Slight loss of crestal bone ( Kamansky F.W. et al ) Burn mark on the root surface. Not suitable for thin gingiva .

68. Whilelmsen et al Whilelmsen et al reported: 1. cemental destruction with subsequent impaired cementogenesis 2.lack of epithelial and connective tissue reattachment 3.significant recession of free gingival margin 4.Apical positioning of sulcular epithelium 5.Slight loss of crestal alveolar bone 6.Burn marks on the root surfaces where the electrode contacted

69. Technique Anesthesia A drop of aromatic smelling oil. Complete seating of electrodes in handpiece . Light pressure and quick ,deft stokes. 7mm per second 5-10 seconds between each stroke. Power selector dial ,as recommended.

70. Healing after electrosurgery Wounds by fully rectified filtered current in a healthy gingiva of adult males showed epithelial bridging at 48 hours and complete clinical healing at 72hrs However as stated by Malone and Kelly (DCNA 1982;26(4);851 ) the use of ORINGER’S SOLUTION……………enhanced healing to 3 to 5 days Kalkwarf , K.L., Krejci , R.F. and Wentz, F.M., 1981. Healing of electrosurgical incisions in gingiva : early histologic observations in adult men.  The Journal of prosthetic dentistry ,  46 (6), pp.662-672.

71. Recent Advances In 1978, Van der Velden and De Vries studied the forces applied to the sulcus during various dental procedures. They observed a tearing of the epithelial attachment as soon as pressure of 1N/mm2 was applied to the marginal gingiva . This attachment was destroyed when the pressure exceeded 2.5N/mm2. Al Shayeb , K.N., Turner, W. and Gillam , D.G., 2014. Accuracy and reproducibility of probe forces during simulated periodontal pocket depth measurements.  The Saudi dental journal ,  26 (2), pp.50-55. Expasyl retraction paste

72. Recent Advances The pressure applied by a retraction cord in this region is between 5 and 10N/mm2 (depending on the number of cords inserted into the sulcus ). A simple periodontal probe exerts a pressure between 1 and 2N/mm2. To separate the marginal gingiva from the human tooth at a distance of 1.5 mm, it is necessary to apply a pressure of 0.1N/mm2. The conclusion of these studies was that gingival retraction should be accomplished under a pressure of between 0.1 and 1N/mm2 to avoid tearing of the epithelial attachment. Velden , U. and Vries , J.H., 1978. Introduction of a new periodontal probe: the pressure probe.  Journal of Clinical Periodontology ,  5 (3), pp.188-197.

73. Recent Advances COMPOSITION 1) Kaolin 66.75% 2) Water 23.36% 3) AlCl3 6.54% 4) Colorant 1.02% 5) Essential oil of lemon 0.33%

74. Expasyl

75. Recent Advances Magic Foam Magic FoamCord is a new non- hemostatic gingival retraction system by Coltène / Whaledent . Magic FoamCord is reportedly the first expanding vinyl polysiloxane material designed for retraction of the gingival sulcus without the potentially traumatic and time-consuming packing of retraction cord. Magic FoamCord material is syringed around the crown preparation margins and a cap ( Comprecap ) is placed to reportedly maintain pressure . After five minutes, the cap and foam are removed and the tooth is ready for the final impression.

76. Recent Advances

77. Recent Advances Gingi Trac GingiTrac is a medium-viscosity, vinyl polysiloxane (VPS) gingival retraction paste with 15% ammonium aluminum sulfate (alum) that gently displaces the gingiva from the tooth and stops bleeding. When used with GingiCap ™ compression caps, the mechanical bite pressure of GingiCap combined with the astringent action of aluminum sulfate works to control bleeding and seepage in just minutes. GingiTrac cleans up easily and completely, without tissue trauma.

78. Recent Advances Marco Ferrari et al in 1996 they found merocel a synthetic material that is specifically chemically extracted by a biocompatible polymer ( hydroxylate polyvinyl acetate) Merocel

79. 3M™ ESPE™ Astringent Retraction Paste

80. Meta Analysis of Cord Vs Cordless Technique

81. References 1.Donovan T.E. et al: Review and survey of medicaments used with gingival retraction cords. J.P.D.1985 vol.58 pg.525-531 2.Miller I.F:Fixed dental prostheses. J.P.D.1958 vol.8 pg.483-495 3.Ruel J. et al:Effects of retraction procedure on periodontium of humans. J.P.D.1980 vol.44 pg.508-514 4.Reiman B.Milford:Exposure of subgingival margins by non-surgical gingival displacement. J.P.D.1976 vol.436 pg.649-654.

82. References 5.Barkmier WW ,Williams H.W.:Surgical methods of gingival retraction for restorative dentistry. J.A.D.A. 1978,vol.96,pg.1002-1007 6.Benson D.W et al:Tissue displacement methods in fixed prosthodontics . J.P.D.1986,vol.55,pg.175-182 7.La Forgia A:Cordless tissue retraction for fixed prostheses J.P.D.1967,vol.17,pg.379 8.Buchanan W.T,Thayer K.E.:Systemic effeccts of epinephrine-impregnated retraction cords in fixed partial denture prosthodontics . J.A.D.A. 1982,vol.104,pg.482 9.Zeena Raja,Chandrashekharan Nair A clinical study on gingival retraction. A survey on the use of gingival retraction cords by dental professional. JIPS 2003,vol.3 pg.21,30

83. References 10.W.D.Mello,V.Chitre et al:Gingival retraction cords-their role in tissue displacement:A Review JIPS2003,vol.3,pg.16 11.Charbeneau G.T. et al Operative Dentistry,Philadelphia 1966.Lea and febiger 12.Gillmore H.W. et al Operative Dentistry,4 th edi.st.Louis 1982.C.v.mosby co. 13.Flocker J.E:Electrosurgical management of soft tissue and restorative dentistry. DCNA 1980 vol24 pg 247. 14.Jonston J.F,Phillips R.W. modern practice in crown and bridge prosthodontics.4 th edi . Philadelphia,Saunders co. 15.Shillingburg H.T etal . Fundamentals of fixed Prosthodontics.3r edi.quintessence pub.co

84. References 16.Rosenstiel,Land,Fugimoto - Contemporary Fixed Prosthodontics 3 rd edi . The mosby co. 17. Marco Ferrari et al 1996, JPD 75; 242-7. 18. Asbjorn Jokstad , JPD 1999, 81; 258-61. 19. Ferenc Csempesz et az , JPD 2003; 89: 45-9. 19. Charles J. Goodaru , JPD 1990; 64: 1-12. 20. Klug G. Richard, JPD 1966; 16: 955-961. 21. Azzi et al, JPD 1983; 50: 561 22. William H. Liebenberg, JADA 1993; 124: 92-102.

85. References Land,Rosenstiel and Sandrik JPD july 1994:72(1);4-7 Ronald D Woody and Amp Miller JPD aug 1993:70(2);191-192 DCNA 1982,26(4);759-780 www.ultradent.com www.valleylab.com Haemostatic agents used in periradicular surgery: an experimental study of their efficacy and tissue reactions by : T. von Arx , S. S. Jensen, S. Hänni , R. K. Schenk (2006); International Endodontic Journal Volume 39 Issue 10 Page 800 - October 2006 Expa syl a unique clinical technique;JADA 2003 nov,134(11);1485