Crown lengthening

Types of crown lengthening,maintainence of biological width,techniques of crown lengthening.

1. CROWN LENGTHENING

2. Introduction Rationale Sequence of treatment Biologic width Ferrule Crown lengthening and techniques Conclusion Points to remember References CONTENTS

3. Periodontal health is the sine qua non, a prerequisite of successful comprehensive dentistry. Active periodontal infection must be treated and controlled before the initiation of restorative , Aesthetic and implant dentistry To achieve the long term therapeutic targets of comfort, good function, treatment predictability ,longevity and maintainence care. INTRODUCTION

4. RATIONALE FOR PERIODONTAL THERAPY

5. To prepare periodontium for restorative dentistry- SEQUENCE OF TREATMENT CONTROL OF ACTIVE DISEASE Emergency treatment Extraction of hopeless teeth Oral hygiene instructions SRP Reevaluation Periodontal surgery Adjunctive orthodontic therapy PREPROSTHETIC SURGERY Management of mucogingival problems Preservation of ridge morphology after tooth extraction Crown lengthening procedures Alveolar ridge reconstruction

6. “When the clinician is presented with a patient with any stage of periodontal involvement, this condition must be treated before one can contemplate any restorative dentistry”

7. The appearance of the gingival tissues surrounding the teeth plays an important role in the esthetics of the mouth. Abnormalities in symmetry and contour can significantly affect the harmonious appearance of the natural or prosthetic dentition

8. nowadays, patients have a greater desire for more esthetic results which may influence treatment choice. An ideal appearance necessitates healthy and inflammation-free periodontal tissues

9. CROWN LENGTHENING The concept of crown lengthening was introduced by D.W C ohen (1962)

10. CLINICAL CROWN-crown visible in the oral cavity ANATOMIC CROWN- crown till the CEJ( incisal edge to CEJ)

11. RATIONALE The rationale of crown lengthening is to re establish the biologic width (e.g. the natural distance between the base of the gingival sulcus and the height of the alveolar bone) in a more apical position to avoid a violation that may result in bone resorption, gingival recession, inflammation or hypertrophy.

12. To provide retention form to allow for proper tooth preparation Impression procedures Placement of restorative margins To adjust gingival levels for esthetics. WHY IS IT PERFORMED??

13. INDICATIONS

14. Inadequate crown to root ratio Non restorability of caries or root fracture Esthetic compromise High furcation CONTRAINDICATIONS Inadequate predictability Tooth arch relationship inadequancy Compromise of adjacent periodontium or esthetics Insufficeient restorative space Non maintainability

15. Clinical evaluation Sulcus depth Biologic width Osseous crest Pulpal involvement Apical extent of fracture Gingival health & Amount of attached gingival tissue EVALUATION BEFORE CROWN LENGTHENING Furcation location Loss of mesial distal or occlusal space Anticipated final margin placement Lip line (at rest and smiling)

16. RADIOGRAPHIC ANALYSIS

17. BIOLOGIC WIDTH Defined as the physiologic dimension of the junctional epithelium and connective tissue attachment. Measurement is relatively constant-2mm+/_30% (2.04mm). Healthy gingival sulcus-0.69mm The Original Concept of ‘biological width’, arise from the work of Garguilo ,Wentz and Orban (1961)- who gave the dentogingival complex and established the dimensional averages as 2.04mm Biologic width is essential for preservation of periodontal health and removal of irritation that might damage the periodontium

18. ‘ Owing to the concept of ‘biologic width’ there should be 3 mm (recommended) of supracrestal tooth tissue between bone and the margins of the restoration’.

19. Some authors have stated different concepts on biologic width. In contemporary practice, it generally is accepted that a 3-mm distance would significantly reduce the risk of periodontal attachment loss induced by subgingival restorative margins. The margin placement should be no more than 0.5 mm into gingival sulcus – to avoid damage to the ‘biologic width’ and facilitate plaque control.

20. IMPORTANCE OF BIOLOGIC WIDTH So the authors have reasoned that “adding the 1 mm to the average 2 mm of the biologic width establishes a minimum dimension of 3 mm coronal to the alveolar crest is necessary to permit proper healing and proper restoration of the tooth

21. Clinical method- EVALUATION OF BIOLOGIC WIDTH VIOLATION If a patient experiences tissue discomfort when the restoration margin levels are being assessed with a periodontal probe, it is a good indication that the margin extends into the attachment and that a biologic width violation has occurred

22. The signs of biologic width violation are: Chronic pain and progressive gingival inflammation around the restoration, bleeding on probing, Localized gingival hyperplasia with minimal bone loss, Gingival recession, pocket formation, clinical attachment loss and alveolar bone loss.

23. The biologic width can be identified by probing under local anesthesia to the bone level (referred to as “sounding to bone”) and subtracting the sulcus depth from the resulting measurement . If this distance is less than 2 mm at one or more locations, a diagnosis of biologic width violation can be confirmed. Radiographic interpretation – Can identify interproximal violations of biologic width, but are not of diagnostic because of tooth superimposition BONE SOUNDING/TRANSGINGIVAL PROBING( Vavacek et al 1994)

24. BIOLOGIC WIDTH CATEGORIZATION Kois (1994) stated that only 3mm is necessary to satisfy the requirements for a stable biologic width.

25. Kois in 2000, proposed three categories of biological width based on the total dimension of attachment and the sulcus depth following bone sounding measurements. Namely: normal crest, high crest and low crest. the mid-facial measurement is 3.0 mm and the proximal measurement is a range from 3.0 mm to 4.5 mm. Normal Crest occurs approximately 85% of time. In these cases, the gingival tissue tends to be stable for a long term. Therefore, a crown margin which is placed 0.5 mm subgingivally tends to be well-tolerated by the gingiva. NORMAL CREST

26. High Crest is an unusual finding in nature and occurs approximately 2% of the time. There is one area where High Crest is seen more often: In a proximal surface adjacent to an edentulous site. In the High Crest patient, the mid-facial measurement is less than 3.0 mm and the proximal measurement is also less than 3.0 mm in this situation. I t is commonly not possible to place an intracrevicular margin because the margin will be too close to the alveolar bone, resulting in a biologic width impingement and chronic inflammation . HIGH CREST

27. T he mid-facial measurement is greater than 3.0 mm and the proximal measurement is greater than 4.5 mm. Low Crest occurs approximately 13% of the time . Traditionally, the Low Crest patient has been described as more susceptible to recession secondary to the placement of an intracrevicular crown margin. LOW CREST

28. Why recession in low crest ?? When retraction cord is placed subsequent to the crown preparation, the attachment apparatus is routinely injured. As the injured attachment heals, it tends to heal back to a Normal Crest position, resulting in gingival recession. LOW CREST STABLE LOW CREST UNSTABLE Some Low Crest patients are susceptible to gingival recession while others have a quite stable attachment apparatus. The difference is based on the depth of the sulcus , which can have a wide range.

29. LOW CREST Recession

30. Importance of determining the crest category This allows the operator to determine the optimal position of margin placement, as well as inform the patient of the probable long-term effects of the crown margin on gingival health and esthetics. Based on the sulcus depth the following three rules can be used to place Intra- crevicular margins:

31. A clinician is presented with three options for margin placement: 1. Supragingival- It has the least impact on the periodontium. This margin location has been applied in non-esthetic areas. 2. Equigingival - The use of equigingival margins traditionally was not desirable because they were thought to favour more plaque accumulation than supragingival or subgingival margins, and therefore result in greater gingival inflammation. 3. Subgingival - Restorative considerations (caries and tooth deficiencies) will frequently dictate the placement of restoration margins beneath the gingival tissue crest. Investigators have correlated that sub gingival restorations demonstrated more quantitative and qualitative changes in the micro flora, increased plaque index, gingival index, recession, pocket depth and gingival fluid MARGIN PLACEMENT

32. A ferrule is a metal ring or cap intended for strengthening . Glossary of Prosthodontic Terms defines a ferrule as a metal band or ring used to fit the root or crown of a tooth Sorensen and Engelman redefined the ferrule effect as “a 360-degree metal collar of the crown surrounding the parallel walls of the dentine extending coronal to the shoulder of the preparation.” FERRULE LENGTH

33. Smukler & Chaibi (1997) recommended some of the following pre surgical analysis PRESURGICAL ANALYSIS Determine the finish line prior to surgery If non determinable it should be anticipated Transcrevicular , circumferential probing prior to surgery is performed for establishing the biologic width-(surgical and contralateral site) The biologic width requirements will determine the level of alveolar bone removal

34. The combination of biologic width & prosthetic requirements determine the total amount of tooth structure necessary for exposure. Tooth surface topography, anatomy, & curvature are analysed for determining a)osseous scallop b)gingival form To plan a crown-lengthening procedure, a dentist must think in three dimensions. In addition, he or she should be concerned about the quantity and quality of residual gingival tissues left behind after the resected tissue has healed completely . Maynard and Wilson recommended a minimum of 3 mm of attached gingiva in the presence of subgingival restorative therapy so care should be taken before excising the tissue

35. TREATMENT AND TECHNIQUES

36. Ernesto (2004) has proposed the following classification : Type I Type II Type III Type IV CLASSIFICATION OF AESTHETIC CROWN LENGTHENING

37. Type I Advantages -May be performed by the restorative dentist. Provisional restorations of the desired length may be placed immediately

38. Type II characterized by soft tissue dimensions that allow the surgical repositioning of the gingival margin No osseous re contouring, but temporary violation of biological width. STAGE 1 Gingivectomy and amount of crown exposed STAGE 2 After healing, flap surgery is done and required amount of ostectomy done to maintain biologic width

39. Advantages Will tolerate a temporary violation of the biologic width Allows staging of the gingivectomy and osseous contouring procedures. Provisional restorations of the desired length may be placed immediately Disadvantages- Requires osseous contouring. May require a surgical referral

40. Type III In type III bone sounding may reveal a scenario where repositioning of the gingival margin will result in the exposure of the osseous crest. It is inappropriate to refer these patients without providing a surgical template derived from a relevant esthetic blue print. Surgical template is used that serve as a guide during surgery following flap reflection

41. Relationship between anticipated clinical crown and alveolar crest level is established and maintained through bone cutting procedure. Flaps repositioned coronally rather than apically to maximise tissue preservation After osseous surgery healing, gingivectomy is done to establish gingival position without violating biological width.

42. TYPE IV Gingival excision compromised by insufficient amount of attached gingiva. Apically positioned mucoperiosteal flap with or without osseous contouring

43. I.Surgical – A. Gingivectomy Conventional ( Scalpel or Kirkland knife) Laser Electrocautery B. Surgical extrusion using periotome . C . Internal Bevel Gingivectomy with or without ostectomy (also referred as flap surgery with or without osseous surgery) D . Apical positioning of flap with or without ostectomy II. Combined (Surgical & non surgical) -Orthodontic Treatment Treatment for crown lengthening

44. Given by Robicsek (1884 ) Grant etal (1979) – Defined it as the excision of the soft tissue wall of the pathologic periodontal pocket Indications- Sufficient sulcular depth & keratinized tissue No violation of biologic width( > 3 mm) No exposure of bone External bevel gingivectomy

45. PROCEDURE F irstly anasthetise the area Then pocket height is measured with pinpoint marker incisions should be bevelled at 45 ° to the tooth surface Remove the excised gingival tissue Carefully curette the granulation tissue Removal of remaining calculus and necrotic cementum Cover the area with surgical pack

46. Used in Dentistry : 1980s Semiconducator diode laser : soft tissue laser In continuous-wave or gated-pulsed modes Operated in contact mode using a flexible fiber optic delivery system. Laser light at 800 to 980 nm is used. Not interact with dental hard tissues Tissue penetration of a diode laser is less than that of the Nd:YAG laser The rate of heat generation is higher. LASER

47. The chief advantages of laser use are: ( 1) Relatively bloodless surgical and postsurgical course; (2) Ability to coagulate, vaporize, or cut tissues (3) Sterilization of the wound site (4) Minimal swelling and scarring (5) Little mechanical trauma (6) Reduction of surgical time (7) High patient acceptance (8) Reduced postoperative pain, possibly due to the protein coagulum that is formed on the wound surface, thereby acting as a biologic dressing and sealing the ends of the sensory nerves.

48. Laser Scalpel surgery Wound healing Faster Delayed

49. Commonly used alternative to surgical excision of the soft tissues It involves the use of high electrical energy, transmitted to the tip of the instrument in the form of heat generated so as to cauterize the tissues Caution must be taken as can cause irreparable damage to bone (necrosis) and ‘ Cementum burn’. ELECTROSURGERY

50. SURGICAL EXTRUSION USING PERIOTOME Final restoration placed after 2 months. Periodontal pack given. Suture removal done after 10 days. Simple interrupted sutures placed for stability. Teeth was extruded to the desired clinical position using a hemostat Blade of the periotome was placed into the periodontal ligament space and manipulated in walking motion to luxate the tooth without inducing surgical trauma.  Local anesthesia was given

51. Clinical and radiographic evaluation at 3 rd  month suggest that surgical extrusion technique offers several advantages such as preservation of the interproximal papilla, gingival margin position and no marginal bone loss compared with the other conventional surgical techniques.

52. It can also be referred as flap surgery with or without osseous surgery. Flap Surgery Without Osseous Surgery : enough attached gingival should remain after the incisions are made. The initial or inverse bevel incision is made depending upon that how much crown exposure is required. The flap is then raised and after complete scaling and root planning flap is then sutured back in position. Crown Lengthening Surgery Using Internal Bevel Gingivectomy With Or Without Ostectomy ( Undisplaced Flap) .

53. Flap surgery with osseous surgery : It is the most common procedure used for clinical crown lengthening mucoperiosteal flap is raised and the alveolar bone is reduced by ostectomy and osteoplasty Restorative procedures should be delayed until 3 to 6 months post surgery . Provisional restorations may be reshaped at 3 to 4 weeks post surgery but the margins should be placed supragingivally .

54. Indication Crown lengthening of multiple teeth in a quadrant or sextant of the dentition, root caries, fractures . Management of tooth wear cases. (often combined with osseous recontouring ) Less than 3 mm of the soft tissue between the bone and gingival margin Less than adequate Attached gingiva APICALLY REPOSITIONED FLAP FOR CROWN LENGTHENING

55. Contraindication Apical repositioned flap surgery should not be used during surgical crown lengthening of a single tooth in the esthetic zone. 1.Apically repositioned flap without osseous resection This procedure is done when there is no adequate width of attached gingiva, biologic width of more than 3 mm on multiple teeth. 2.Apical repositioned flap with osseous reduction This technique is used when there is no adequate zone of attached gingiva biologic width is less than 3 mm. The alveolar bone is reduced by ostectomy and osteoplasty , to expose the required tooth length in a scalloped fashion, and to follow the desired contour of the overlying gingiva

56. GENERAL RULE

57. Step 1 : Internal bevel incision given (no more than 1 mm of crest of gingiva and directed to the crest of bone) Step 2 : Crevicular incisions made initial elevation of flap Step 3 : Vertical incisions made, extending beyond the MGJ

58. Step 4 : Removal of all the granulation tissue Osseous surgery, if required Flap is displaced Apically Step5 : sling sutures are placed around the tooth to prevent flap from sliding more apically Periodontal dressing placed to prevent coronal shift

59. Combined (Surgical And Non Surgical{Orthodontic} 2 possible approaches to this procedure are – Forced eruption followed by minor Osseous resection Forced eruption combined by fibrotomy SLOW ERUPTION RAPID ERUPTION Forced eruption- Heithersay and Ingber Two concepts of forced eruption-Starr F orced eruption of multiple teeth- Frank,used various techniques to extrude teeth using removable devices or fixed brackets.

60. Disadvantages of forced eruption Disparity in root width between the erupted and the contralateral teeth Need for fixed appliances Subsequent retention of the orthodontically treated tooth So, 2 nd alternative- forced eruption followed by fibrotomy . Disadv antages- Patient must return biweekly basis for resection of the supracrestal fibres , followed by root planing to the level of bone crest, until desired degree of eruption is obtained. Retention period is required

61. COMPLICATIONS OF CROWN LENGTHENING Possible poor aesthetics due to 'black triangles’ Root sensitivity Root resorption Transient mobility of the teeth . Gingival retraction – change of marginal gingiva contour C linical tooth crown higher than adjacent teeth Unfavorable crown-root relationship.

62. HEALING AFTER CROWN LENGTHENING Restorative procedures must be delayed until new gingival crevice develops after periodontal surgery. In non esthetic areas, the site should be re-evaluated atleast 6 weeks post surgically prior to final restorative procedures. In esthetic areas, a longer healing period is recommended to prevent recession. Wise recommends 21 weeks for soft tissue gingival margin stability. Therefore, restorative treatment should be initiated after 4-6 months. The margin of the provisional restoration should not hinder healing before the biologic width is established by surgical procedures. Shobha et al. in a study on clinical evaluation of crown lengthening procedure had concluded that the biologic width can be re-established to its original vertical dimension along with 2 mm gain of coronal tooth structure at the end of six months.

63. After a 2-3 week post surgery period, temporary crowns may be used until there has been full healing and the gingival margin is in a stable position. Before tooth restoration the gingiva should be healthy without any sign of inflammation. Then these rules could be followed If gingival sulcus is 1.5 mm or less, then margins of restoration is prepared to 0.5 mm subgingivally; If gingival sulcus is 1.5 – 2 mm, then margins of restoration is prepared to 0.7 mm subgingivally; If gingival sulcus more than 2 mm, especially in esthetical area from vestibular side, then gingivectomy is recommended and margins of restoration i s prepared to 0.5 mm subgingivally. RESTORATION OF TEETH

64. CONCLUSION

65. If the tooth in question has a hopeless prognosis or the osseous surgical procedure would create Poor Crown: root Furcation involvement Mobility, or Esthetics problems, Crown lengthening should be avoided and extraction may be indicated

66. Points to remember

67. Crown lengthening: indications and techniques. Dent Update 2008 Carranza’s clinical periodontology . 10 th edition Surgical crown lengthening. Dent Update 2007;34:462-468 Crown Lengthening Procedures- A Review Article Dr . Gunjan Gupta IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) Biological width: The silent zone Amit Parashar Tissue Management in Restorative Dentistry J . WILLIAM ROBBINS, DDS, MA Crown lengthening and restorative procedures in the esthetic zone-Perio 2000 Surgical lengthening of the clinical tooth crown Liudvikas Planciunas , Alina Puriene , Grazina Mackeviciene,2006 Three different surgical techniques of crown lengthening : A comparative study Ramya Nethravathy,2013 Aesthetic crown lengthening MICHAEL G. JORGENSEN & HESSAM NOWZARI-Perio2000 Google images REFERENCES