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Contemporary Crown-lengthening Therapy

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  • 1. ContemporaryCrown-lengthening Therapy 2010 Jun;141(6):647-55. Timothy J. Hempton, DDS; John T. Dominici, DDS, MS School of Dental Medicine, Tufts University, Boston, MA, USA. Presenter: R2 鄭瑋之 Instructor: VS 陳娟娟 Date: 2012-11-30
  • 2. Introduction• Significant caries or subgingival fractures• Clinical findings vs. patients concerns  extracted or restored?• An age of dental implants
  • 3. Outlines
  • 4. A. Esthetic and functional concernsB. Biological widthC. Ferrule length
  • 5. A. Esthetic and functional concerns – Exposure of subgingival caries – Exposure of a fracture – High lip line, delayed passive eruption, excess gingival display – “▼ “ contact area~interdental osseous crest >5 mm
  • 6. B. Biological widthGargiulo and colleaguesGargiulo and colleagues
  • 7. B. Biological widthChronic inflammation Ingber and colleagues Ingber and colleaguesBone resorption Biologic width > 3 mm Reduce periodontal attachment loss induced by subgingival restorative margins
  • 8. B. Biological widthChronic inflammation Ingber and colleagues Ingber and colleaguesBone resorption Biologic width > 3 mm Reduce periodontal attachment loss induced by subgingival restorative margins
  • 9. C. Ferrule length – A metal band or ring used to fit the root or crown of a tooth. (The Journal of Prosthetic Dentistrys 2005) – A 360-degree metal collar of the crown surrounding the parallel walls of the dentine extending coronal to the shoulder of the preparation. (Sorensen and Engelman)
  • 10. C. Ferrule length Foundation restorative 1~2mm the ferrule height material forces of occlusion dispersed onto the PDL rather than post and coreLibman and Nicholls 1.5 mm Libman and Nicholls 1.5 mmApical 1/3 of the preparation the greatest retention andresistance of the restoration
  • 11. • Biological width of 3 mm• Ferrule length of 1.5 mmGegauff: 1) Biomechanical leverage: more apicalthinner cross section 2) Unfavorable crown-root ratio Orthodontic extrusion
  • 12. A. Soft tissueB. Osseous management – The extent of bone resection – Contraindications to osseous resection
  • 13. A. Soft tissue – Flap design: height of gingiva on the facial & lingual aspects – Gingivectomy: with scalpel, electrosurge, radiosurge or laser – Maynard and Wilson: ≧3 mm of attached gingiva  subgingival OD tx. – If post-op height of gingiva would <3mm  apically positioned flap – If bone crest~free gingival margin <3 mm elevated flap for access
  • 14. B. Osseous management – 3D analysis : occlusoapical, mesiodistal, buccolingual – Ostectomy and osteoplasty: hand chisels, high-speed rotary instrumentation or a piezoelectric cutting device – Moistened constantly during the procedure – Failure to eliminate osseous deformities poses a risk of pockets
  • 15. B. Osseous management – The extent of bone resection • Class V: one-tooth flap with 2 vertical releasing incisions to gain 3 mm biological width. • Class II or cr.: interproximal bone – Contraindications to osseous resection • Crown-root ratio • Furcation region with the root trunk
  • 16. • Apically positioned flap with osseous resection  biological width reestablishes itself• Flap margin placed at osseous crest  post-op vertical gain in supracrestal soft tissues averages 3 mm• When the final tooth preparation can begin and when impressions?• Which the treated dentition is of esthetic concern to the patient?
  • 17. • Lanning and colleagues: coronal advancement of the healing tissues from the osseous crest averages 3 mm by 3 months’ time after surgery. 6 months after surgery, no further significant changes• Brägger and colleagues: during a 6- month healing period, periodontal tissues were stable• The waiting period after a crown- lengthening procedure: > 6 months
  • 18. • Wound healing1. Resective procedure used to induce recession surgically2. The underlying osseous structure is critical in the final wound healing.3. Underlying bone must be evaluated in 3-D4. Class II or cr.: changes in the MD dimension to establish positive architecture.
  • 19. • Wound healing5. More cleansable gingival embrasure areas6. The final position of the free gingival margin can occur at 3 months/6 months after surgery7. Esthetic zone, a waiting period of 6 months is advisable
  • 20. Case Report• 58 y/o female• Subgingival restoration over #15• Adequate for osseous resective therapy
  • 21. Case Report• Flap: from #16 (D) to #13 (M) line angle• Establish 4.5 mm of supraosseous tooth structure on the buccal and palatal aspects  Biological width/ferrule.
  • 22. Case Report• Area after the osseous resection
  • 23. Case Report• Positioned the flaps apically by means of periosteal sutures, which attaches the flap at an apical level to connective tissue still present on the facial aspect of the buccal bone.• 8 wks later
  • 24. Case Report• Photograph and radiograph 8 years later
  • 25. Conclusion • Wound healing1. Crown-lengthening surgery can be a viable option for OD tx. or esthetics.2. Evaluate the complete periodontal condition and disclose all possible treatment options.3. In cases involving the possibility of a negative esthetic outcome, compromise to the support of the dentition.4. Extraction and implant therapy or conventional prosthetic therapy may be a more compelling solution.
  • 26. References1. Contemporary crown-lengthening therapy: a review. Hempton TJ, Dominici JT. School of Dental Medicine, Tufts University, Boston, MA, USA. 2010 Jun;141(6):647-55.
  • 27. Thank you for yourattention!!