8. Crown Lengthening Flashcards
What is crown lengthening
procedure to increase the length of the clinical crown
What is the difference between the clinical and anatomic crown
Clinical crown= coronal to the alveolar crest
Anatomic crown= coronal to the CEJ
What is ferrule
Supra-marginal dentin engaged by the restoration
T/F Can crown lengthening increase ferrule
yes
Benefits of ferrule
aids in retention by creating a stronger tooth/restoration interfece
Indications for crown lengthening
- Short clinical crown (poor retention)
- Improve esthetics (anterior teeth gummy smiles)
- Subgingival caries or root resorption (subgingival margins invading biologic width)
- Reduce excessive gingival display
- Root fracture in coronal third
- Pin or post perforation in coronal third
Causes of excessive gingival display
- Occlusal wear
- Short upper lip
- Longer than usual maxila
Contraindications for crown lengthening
- Inadequate treatment plans
- Poor oral hygiene
- No strategic value for the tooth
- Severe peridontitis
Biologic width is _mm
2
The biologic width consists of what contents
-JE
-Supracrestal CT fiber complex
^^In this order from coronally to more apically
How much tooth structure is needed for retention
3-4 mm
T/F Osseous reduction is not usually required around the entire circumference of the tooth
t
What happens if the biologic width is violated
- Chronic inflammation
- Progressive attachment loss
- Pocket formation
- Localized bone loss
- Gingival hyperplasia
Other alternative surgeries for crown lengthening at
- Gingivectomy
- Flap surgery
- Ortho extrusion
Purpose of a gingivectomy is
- Eliminated tissues that form the pocket
- Used if overgrown or hyperplastic gingiva is interfering with restorative procedures
T/F Gingivectomy will lengthen the clinical crown
f- EXCEPT for a minimal area of supracrestal fiber attachment
How much keratinized gingiva is needed for a gingivectomy
at least 4 mm
Flap surgery utilizes what kind of incision
reverbevel or internal bevel incision
Buccal flaps and mandibular flaps are typically (marginal/submarginal)
either
Palatal flaps are (marginal/submarginal)
submarginal
A min. of _mm of sound tooth structure should be exposed for flap surgery
3mm (generally want 3-5mm)
Benefits of orthodontic extrusion over crown lengthening
-Maintains shape of papilla
Disadvantages of ortho extrusion over crown lengthening
-Osseous tissues may move with the tooth and supraosseous tooth structure may not change
Post- op healing time after CL
6 weeks
