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.

Introduction

• Significant caries or subgingival fractures

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

• An age of dental implants

Outlines

A. Esthetic and functional concerns

B. Biological width

C. Ferrule length

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

B. Biological width

Gargiulo and colleaguesGargiulo and colleagues

B. Biological width

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

Ingber and colleaguesIngber and colleaguesChronic inflammationBone resorption

B. Biological width

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

Ingber and colleaguesIngber and colleaguesChronic inflammationBone resorption

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)

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 mmLibman and Nicholls 1.5 mm

• 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

A. Soft tissue

B. Osseous management– The extent of bone resection

– Contraindications to osseous resection

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

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

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

• 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?

• 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

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

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

Case Report

• 58 y/o female• Subgingival restoration over #15• Adequate for osseous resective 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.

Case Report

• Area after the osseous resection

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

Case Report

• Photograph and radiograph 8 years later

• 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

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.

Thank youfor your

attention!!