contemporary crown-lengthening therapy

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Contemporary Crown- lengthening Therapy Presenter: R2 鄭鄭 Instructor: VS 鄭 鄭鄭 Date: 2012-11-30 2010 Jun;141(6):647-55. Timothy J. Hempton, DDS; John T. Dominici, DDS, MS School of Dental Medicine, Tufts University, Boston, MA, USA.

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Page 1: Contemporary Crown-lengthening Therapy

Contemporary Crown-lengthening

Therapy

Presenter: R2 鄭瑋之Instructor: VS 陳娟娟

Date: 2012-11-30

2010 Jun;141(6):647-55.Timothy J. Hempton, DDS; John T. Dominici, DDS, MS

School of Dental Medicine, Tufts University, Boston, MA, USA.

Page 2: Contemporary Crown-lengthening Therapy

Introduction

• Significant caries or subgingival fractures

• Clinical findings vs. patients' concerns extracted or restored?

• An age of dental implants

Page 3: Contemporary Crown-lengthening Therapy

Outlines

Page 4: Contemporary Crown-lengthening Therapy

A. Esthetic and functional concerns

B. Biological width

C. Ferrule length

Page 5: Contemporary Crown-lengthening Therapy

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

Page 6: Contemporary Crown-lengthening Therapy

B. Biological width

Gargiulo and colleagues

Page 7: Contemporary Crown-lengthening Therapy

B. Biological width

Biologic width > 3 mmReduce periodontal attachment loss induced by subgingival restorative margins

Ingber and colleaguesChronic inflammationBone resorption

Page 8: Contemporary Crown-lengthening Therapy

B. Biological width

Biologic width > 3 mmReduce periodontal attachment loss induced by subgingival restorative margins

Ingber and colleaguesChronic inflammationBone resorption

Page 9: Contemporary Crown-lengthening Therapy

C. Ferrule length– A metal band or ring used to fit the

root or crown of a tooth. (The Journal of Prosthetic Dentistry's 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)

Page 10: Contemporary Crown-lengthening Therapy

C. Ferrule length Foundationrestorativematerial

Apical 1/3 of the preparation the greatest retention and resistance of the restoration

1~2mm the ferrule height forces of occlusion dispersed onto the PDL rather than post and core

Libman and Nicholls 1.5 mm

Page 11: Contemporary Crown-lengthening Therapy

• Biological width of 3 mm• Ferrule length of 1.5 mm

Gegauff:1) Biomechanical leverage: more

apicalthinner cross section2) Unfavorable crown-root ratio

Orthodontic extrusion

Page 12: Contemporary Crown-lengthening Therapy

A. Soft tissueB. Osseous management

– The extent of bone resection

– Contraindications to osseous resection

Page 13: Contemporary Crown-lengthening Therapy

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

Page 14: Contemporary Crown-lengthening Therapy

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

Page 15: Contemporary Crown-lengthening Therapy

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

Page 16: Contemporary Crown-lengthening Therapy

• 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?

Page 17: Contemporary Crown-lengthening Therapy

• 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

Page 18: Contemporary Crown-lengthening Therapy

1. Resective procedure used to induce recession surgically

2. The underlying osseous structure is critical in the final wound healing.

3. Underlying bone must be evaluated in 3-D

4. Class II or cr.: changes in the MD dimension to establish positive architecture.

• Wound healing

Page 19: Contemporary Crown-lengthening Therapy

5. More cleansable gingival embrasure areas

6. The final position of the free gingival margin can occur at 3 months/6 months after surgery

7. Esthetic zone, a waiting period of 6 months is advisable

• Wound healing

Page 20: Contemporary Crown-lengthening Therapy

Case Report• 58 y/o female• Subgingival restoration over #15• Adequate for osseous resective therapy

Page 21: Contemporary Crown-lengthening Therapy

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.

Page 22: Contemporary Crown-lengthening Therapy

Case Report• Area after the osseous resection

Page 23: Contemporary Crown-lengthening Therapy

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

Page 24: Contemporary Crown-lengthening Therapy

Case Report• Photograph and radiograph 8 years later

Page 25: Contemporary Crown-lengthening Therapy

• Wound healing

1. 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.

Conclusion

Page 26: Contemporary Crown-lengthening Therapy

References

1. 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.

Page 27: Contemporary Crown-lengthening Therapy

Thank youfor your

attention!!