Biologic width

biological width in periodontics

1. BIOLOGIC WIDTH PRESENTED BY BIBINA GEORGE GUIDED BY, DR. JAYASHREE A. MUDDA

2. CONTENTS Introduction Interdental BW Concept of BW Categories/ Profiles of BW Margin Placement Evaluation of BW Violation Signs of BW violation Correction of BW Violation BW in Implants BW in Restorative Dentistry Conclusion References

3. INTRODUCTION Biological width is defined as the dimension of soft tissue which is attached to the portion of the tooth coronal to the crest of alveolar bone. ( Gargiulo et al 1961 )

4. Average histological width of connective tissue attachment - 1.07mm. Mean average length of epithelial attachment - 0.97mm Range : 0.71mm-1.35mm . Sulcus depth : 0.6 mm Average combined histological width of connective tissue attachment + Junctional epithelium = 2.04mm (Biologic Width) (Gargiulo et al 1961)

5. On evaluation of cadaver tooth surfaces , Connective tissue attachment was the most consistent measurement based on the mean measurements of : Sulcus depth - 1.34 mm , Epithelial attachment - 1.14 mm and Connective tissue attachment - 0.77 mm . Vacek et al 1994 Further studies by Newcomb (1974 ), Gunay et al (2000), Maynard and Wilson (1979 ) , Tal et al ( 1986)and Nevins and Skurow (1984 ) suggest that violation of biological width must be prevented.

6. INTERDENTAL BIOLOGIC WIDTH Kois and Spear pointed out that the dentogingival complex is 3.0mm facially and 4.5mm to 5.5mm interproximally . They noted that the height of interdental papilla can only be explained by increased scalloping of the bone. Becker and colleagues (1970) defined variation of gingival scalloping as flat scalloped and pronounced scalloped.

7. Spear suggested that additional 1.5 to 2.5mm of interproximal gingival tissue height require the presence of adjacent teeth for maintains of interproximal gingival volume . Without the adjacent tooth the interproximal gingival tissue would flatten out, assuming a normal 3.0mm biologic width . Tarnow and colleagues found that for the gingival tissue to assume complete filling of the interdental space, the distance from the contact point to alveolar crest should not exceeded 5 mm to 5.5mm . Greater distance result in significant loss of alveolar height.

8. CONCEPT OF BIOLOGIC WIDTH Maynard and Wilson (1979) divided the periodontium into 3 dimensions: Superficial physiologic Crevicular physiologic and Subcrevicular physiologic The Subcrevicular physiologic space is analogous to the biologic width described ( Gargiulo et al 1961)

9. CATEGORIES / PROFILES OF B.W 3 categories of biological width based on total dimension of attachment and the sulcus depth following bone sounding measurements : Normal Crest High Crest Low crest Kois,2000

10. NORMAL CREST HIGH CREST LOW CREST Midfacial measurement 3mm < 3mm. > 3mm Proximal measurement Range from 3mm to 4.5mm There is one area where the crest is seen more often, in a proximal surface adjacent to an edentulous site. > 4.5mm. Occurrence aptly 85% of the time. Gingival tissues tend to be stable in patients. 2% of the time aptly 13% of the time

11. The margin of a crown should be placed no closer than 2.5 mm from alveolar bone . Therefore , a crown margin which is placed 0.5 mm subgingivally tends to be well-tolerated by the gingiva 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 More susceptible to recession secondary to the placement of an intracrevicular crown margin. 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

12. MARGIN PLACEMENT

13. Supragingival Equigingival Subgingival Least impact on the periodontium. More plaque accumulation than supragingival or sub gingival margin resulting in gingival inflammation More quantitative and qualitative changes in the microflora Application Non-esthetic areas due to the marked contrast in color & opacity of traditional restorative materials against the tooth Restorative margins can be esthetically blended with the tooth & finished to provide a smooth, polished interface at the gingival margin. Increased plaque index, gingival index, recession, pocket depth and gingival fluid.

14. Advantages of extending restoration gingivally to create adequate resistance and retentive form in the preparation to make significant contour alterations because of caries or other tooth deficiencies to mask the tooth/restoration int 4 erface by locating it subgingivally.

15. EVALUATION OF BIOLOGICAL WIDTH VIOLATION CLINICAL METHOD : If a patient experiences tissue discomfort when the restoration margin levels are being assessed with a periodontal probe Margin has extended into the attachment and biologic width violation has occurred

16. BONE SOUNDING/TRANSGINGIVAL PROBING Biological width can be identified by probing under local anesthesia (referred to as 'sounding to bone') subtracting the sulcus depth from the surrounding measurements. If this distance is < 2mm at one or more locations, a diagnosis of biological width violation can be confirmed . Vavacek et al,1994

17. RADIOGRAPHIC METHOD : Can identify interproximal violations of biologic width. However, on the mesiofacial and distofacial line angles of teeth, radiographs are not diagnostic because of tooth superimposition . Parallel profile radiographic technique has been devised which could be used to measure both length and thickness of the dentogingival unit with accuracy. [

18. violation OF BIOLOGIC WIDTH Signs of biological width biological width violation : 1. Chronic progressive gingival inflammation around the restoration. 2. Bleeding on probing. 3. Localized gingival hyperplasia with minimal bone loss. 4. Gingival recession 5. Pocket formation 6. Clinical attachment loss. 7. Alveolar bone loss.

19. CORRECTION OF BIOLOGIC WIDTH VIOLATION Surgically removing bone away from proximity to the restoration margin. Orthodontic extrusion of the tooth and then moving the margin away from the bone. Advantage of surgical process: Rapid method. Gives more pleasant result if the crown lengthening is done.

20. SURGICAL CROWN LENGTHENING : INDICATIONS CONTRAINDICATIONS Inadequate clinical crown for retention due to extensive caries, root perforation or root resorption within the cervical 1/3rd of the root in teeth with adequate periodontal attachment. Unequal, excessive, or unesthetic gingival levels for esthetics. Teeth with inadequate interocclusal space for proper restorative procedures due to supraeruption . Restorations which violate the biologic width. Deep caries or fracture requiring excessive bone removal. Tooth with inadequate crown root ratio (ideally 2: 1 ratio is preferred). Non-restorable teeth. Tooth with increased risk of furcation involvement. Unreasonable compromise esthetics/adjacent alveolar bone support.

21. Surgical Process – Types: Gingivoplasty Gingivectomy Apical repositioned flap with bone recontouring In these situations the bone should be moved away from the margin by the measured distance of the ideal biologic width , with an additional 0.5 m m as a safety zone.

22. Disadvantage Gingival recession after removal of bone Papillary recession ( interproximal removal ) Creation of an unesthetic triangle of space below the interproximal contacts . (Black triangles)

23. APF without Osseous reduction

24. APF with Osseous reduction

25. Orthodontic Procedures : Slow Extrusion Rapid Extrusion Slowly brings alveolar bone and gingival tissue with it up to the ideal bone level by 0.5mm. Tooth is then stabilized in this new position Then treated with surgery to correct the bone and gingival tissue. Completes in several weeks period. During this period supracrestal fiberotomy is performed weekly in an effort to prevent the tissue and bone following the tooth. Tooth is then stabilized for at least 12 weeks to confirm the position of the tissue and bone Any coronal creep can be corrected surgically.

26. FORCED ERUPTION WITH OSSEOUS SURGERY

27. FORCED TOOTH ERUPTION INDICATIONS CONTRAINDICATIONS Cases where traditional crown lengthening via ostectomy * cannot be accomplished as in anterior area, and also remove bone from the adjacent teeth, which can compromise the function of these teeth Inadequate crown-to-root ratio. Lack of occlusal clearance for the required amount of eruption . Possible periodontal complications.

28. FORCED TOOTH ERUPTION WITH FIBROTOMY TECHNIQUE CONTRAINDICATIONS Fibrotomy is performed with a scalpel at 7-10 day intervals to sever the supracrestal fibers, thereby preventing the crestal bone form following the root in a coronal direction. Crestal bone, and the gingival margin are retrieved at their pretreatment location and the tooth-gingiva interface as adjacent teeth is unaltered. Angular bone defects Ectopically erupted teeth.

29. BIOLOGIC WIDTH AND IMPLANT Most important difference between periodontal and peri-implant tissues periodontal structure fibers run perpendicular the long axis of tooth In implant tissue the fibers from the crest run parallel to implant surface . Peri-implant biologic width is composed of the sulcus, supracrestal epithelium and the connective tissue component.

30. The influence of five different factors on implant biologic width has been evaluated: Surgical technique , Loading time, Abutment material , Implant structure and position , Immediate post extraction insertion . On implant : Junctional epithelium + connective tissue = biologic width 1.88mm+1.05mm = 3.08 mm

31. BIOLOGICAL WIDTH IN IMPLANTS Implant-abutment connection placement – At the gingival level supracrestal to the alveolar bone , the biologic width measurement was similar to natural dentition . At deeper level , the biologic width increased accordingly. Far below the gingival tissue crest , it will impinge on the gingiva and constant inflammation is created. Highly scalloped, thin gingiva is more prone to recession than a flat periodontium with thick fibrous tissue. Implant level should always be placed subgingivally to allow development of desired profile and aesthetics.

32. BIOLOGICAL WIDTH IN RESTORATIVE DENTISTRY If there are no signs of inflammation before the restoration, then the following rules can be followed : If gingival sulcus is ≤ 1.5mm place the margin 0.5mm below the gingival tissue crest. If gingiva sulcus is > 2mm, margins of restoration is prepared 0.7mm subgingivally . If gingival sulcus is > 2mm, in an Esthetic zone from vestibular side. Gingivectomy is recommended Margins of restoration is prepared 0.5mm subgingivally

33. CONCLUSION : The health of periodontal tissue is dependent on properly designed restoration . Incorrectly placed restorative margin and unadapted restoration violates the biologic width. If the margin must be placed subgingivally, other factors to be taken into account are: 1 . Correct crown contour in gingival third. 2. Correct polishing and finishing of the margin . 3. Sufficient zone of attached gingival and no biologic width violation by subgingival margin . Repeated maintenance visits, patient cooperation and motivation are important factor for improved success of restoration procedure with positive periodontal health .

34. REFERENCES: Carranza,10 th and 11 th edition Malathi K, Arjun singh . Biologic width: Understanding and its preservation . Int J Med and Dent Sci 2014 ; 3(1):363-368 . Linkevicius T et al. Stomatologija , Baltic Dental and Maxillofacial Journal, 2008;10(1):27-35. Sharma A, Rahul GR, Gupta B, Hafeez M. Biological width: No violation zone. Eur J Gen Dent 2012;1:137-41 . Srdjak KJ et al. Periodontal and Prosthetic Aspect of Biological Width Part I: Violation of Biologic Width .Acta Stomatol Croat,2000;34(2):195-7. Nugala B, Santosh Kumar BB, Sahitya S , Krishna PM. Biologic width and its importance in periodontal and restorative dentistry. J Conserv Dent 2012;15:12-7. Dhir S. Significance and clinical relevance of biologic width to implant dentistry. J Interdiscip Dentistry 2012;2:84-91 . Aishwarya M, Sivaram G. Biologic width: Concept and violation. SRM J Res Dent Sci 2015;6:250-6 . Oh SL. Biologic width and crown lengthening: Case reports and review. General Dentistry Sept-Oct 2010;e201-5.