Crown lengthening therapy aims to expose more tooth structure for restorative or aesthetic purposes. A 2010 review summarizes key aspects of the procedure, including maintaining at least 3mm of biological width and 1.5mm of ferrule length for improved force distribution and reduced attachment loss. Soft and hard tissue management is also discussed. Osseous resection may take 3-6 months to establish biological width, so impressions and final preparations should wait at least 6 months to allow for stable tissue healing.

1. Contemporary
Crown-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 concerns
B. Biological width
C. 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 width
Gargiulo and colleagues
Gargiulo and colleagues

7. B. Biological width
Chronic inflammation Ingber and colleagues
Ingber and colleagues
Bone resorption
Biologic width > 3 mm
Reduce periodontal
attachment loss induced by
subgingival restorative
margins

8. B. Biological width
Chronic inflammation Ingber and colleagues
Ingber and colleagues
Bone 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 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)

10. C. Ferrule length Foundation
restorative
1~2mm the ferrule height material
forces of occlusion dispersed
onto the PDL rather than post
and core
Libman and Nicholls 1.5 mm
Libman and Nicholls 1.5 mm
Apical 1/3 of the preparation
 the greatest retention and
resistance of the restoration

11. • Biological width of 3 mm
• Ferrule length of 1.5 mm
Gegauff:
1) Biomechanical leverage: more
apicalthinner cross section
2) Unfavorable crown-root ratio
 Orthodontic extrusion

12. A. Soft tissue
B. 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 healing
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.

19. • 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

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 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.

26. 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.

27. Thank you
for your
attention!!