contemporary crown-lengthening therapy
TRANSCRIPT
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 colleagues
B. Biological width
Biologic width > 3 mmReduce periodontal attachment loss induced by subgingival restorative margins
Ingber and colleaguesChronic inflammationBone resorption
B. Biological width
Biologic width > 3 mmReduce periodontal attachment loss induced by subgingival restorative margins
Ingber 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 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 tissueB. 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!!