Crown lengthening- Review Flashcards
Only category in which gingvectomy ALONE is successful:
UNSTABLE low crest
List the objectives to crown lengthening:
- to allow for restoration of tooth (caries removal, clamp placement, etc)
- Increasing crown length for retention or restoration (adequate ferrule)
- Restoration of tooth in harmony with supracrestal attached tissue (biologic width)
- Esthetics via alteration of the gingival labial profile
Functional indications for crown lengthening include: (4)
- SubG restorative margins
- Tooth fracture
- Endo perforations
- Cervical root resorption
Esthetic indications of crown lengthening: (3)
- Excessive gingival display
- Gingival overgrowth (meds)
- Altered passive eruption
List the components of supracrestal attached tissue (biological width)
CT attachement (1.07 mm) + JE (0.97mm) =0.97 mm 2.04mm
T/F: Epithelium gets its blood supply and nutrients from the underlying connective tissue
True
What is the most consistent dimension of the surpacrestal attachement?
Most variable dimension?
Consistent= CT attachment (1.07mm)
Variable= JE (0.97 mm)
Vertical axial wall that surrounds the tooth that is desired every time a crown is fabricated to help resist fracture and/or crown displacement
ferrule
T/F: You need at least 1mm of ferrule (natural tooth structure ) circumferentially beyond the core
false- you need at least 2mm of ferrule
What bur is used for osteoPLASTY?
large round bur
What bur is used for ostECTOMY
end cutting bur
Before beginning a crown lengthening procedure, the tooth should ideally be:
caries free and provisionalized
T/F: Before beginning the crown lengthening procedure, the tooth should ideally be caries free AND provisionalized
true
With a crown lengthening procedure, osectomy is generally only required on the:
facial
At end of crown lengthening procedure, a well-fitting temporary crown should be placed back o the tooth to prevent:
migration
When should the final restoration be placed following crown lengthening procedure?
minimum 6 weeks to 6 months
T/F: If in doubt following a crown lengthening procedure, a good rule of thumb is to wait 1-6 months before final restoration placement
false- 3-6 months (6 weeks to 6 months)
CEJ should be approximately ____ from the osseous crest
2mm
The _____ should be approximately 2mm from the osseous crest
CEJ
The gingival margin should be _____ coronal to the CEJ (covering anatomic crown)
0.5-2mm
The _____ should be 0.5-2mm _____ to the CEJ, covering the anatomic crown
gingival margin; coronal
As the tooth breaks through the gingiva, it erupts until it meets its antagonist and occludes and then ceases or slows. This is referred to as:
active eruption
T/F: Eruption potential continues through out life (think supraeruption of tooth when there is no opposing tooth)
true
- Shift of tooth itself (no gingival movement)
- As tooth breaks through gingival it erupts until meets antagonist and occludes, then eruption ceases/slows
- Eruption POTENTIAL continues throughout life (think supra eruption with a tooth lacking an antagonist)
Active eruption
Morphological variant where CEJ is LESS THAN 2 mm from the osseous crest
Altered active eruption
Altered active eruption can result in _____ and be exacerbated by ____.
shorter than normal clinical crown; orthodontic brackets
Apical shift of dentogingival junction (gingival movement NOT tooth)
passive eruption
Passive eruption occurs during and after active eruption (T/F)
True
Eruption in which the tooth does NOT move, rather the gingiva moves apically:
passive eruption
What direction does the gingiva move in passive eruption?
apically
List the stages of passive eruption:
- JE rests on enamel surface
- JE rests on enamel and cemental surface apical to CEJ
- Epithelium attachment rests on cementum
- Epithelial attachment migrates apically
Normal passive eruption concludes when:
Sulcus base is at the level of the CEJ, placing the gingival margin 1-2mm coronal to the CEJ
When passive eruption does not progress past stage 1 or 2, (seen in about 12% of adult population)
altered passive eruption
Altered passive eruption is seen in about ____% of adult patient
12%
Morphological variant where gingiva is more than 2mm coronal to the CEJ:
altered passive eruption
Altered passive eruption can be exacerbated by:
inflammation and medications
Altered active eruptions can be exacerbated by:
orthodontic brackets
Kois categories for supracrestal tissue attachment include:
- Normal crest (85%)
- High crest (2%)
- Low crest (13%)
Low crest can further be categorized by:
stable vs. unstable
Provide the Kois category for the following situation:
bone sounding 3mm from gingival crest to alveolar crest mid facial
3-4.5 mm from gingival crest to alveolar crest at line angles
normal crest (85%)
Provide the Kois category for the following situation:
bone sounding of less than 3mm from gingival crest to alveolar crest mid facial
less than 3 mm from gingival crest to alveolar crest at line angles
high crest (2%)
Provide the Kois category for the following situation:
bone sounding of greater than 3mm from gingival crest to alveolar crest mid facial
more than 4.5 mm from gingival crest to alveolar crest at line angles
sulcus must be probed in order to determine sulcus depth in addition to bone sounding
low crest (13%) (stable vs. unstable)
- normal attachment apparatus (approximately 2mm)
- greater than normal sulcus depth
- prone to recession due to the deep sulcus depth and unsupported gingival crest
- only category in which a gingivectomy alone is successful
UNSTABLE low crest
T/F: In an unstable stable low crest, there is a greater than normal sulcus depth
true
- normal sulcus depth
- longer than normal attachment apparatus
- susceptible to gingival rebound after crown lengthening due to inadequate ostectomy to accommodate the longer attachement apparatus
stable low crest
What type of low crest is more susceptible to gingival rebound following crown lengthening?
Stable low crest
What would be the indications for gingivectomy only?
Unstable low crest
Describe a clinically esthetic smile:
- shows 75%-100% of crowns and interproximal gingiva (papilla)
- symmetrical display in harmony between the maxillary gingival line and the upper lip
- lower lip parallel to the incisal edges of maxillary teeth and in close approximation
In an esthetic smile, there should be parallelism between the ____ & ____ to create facial harmony
inter pupillary line & commissural line
Position of the upper lip relative to the maxillary incisors and gingiva during a natural full smile:
smile line
List the normal variation & minimum normal values of the following teeth to have an esthetic smile:
A) central
B) lateral
C) canine
A) central= 11-13 (10)
B) lateral= 10 (9)
C) canine= 11-13 (10)
T/F: To accomplish an esthetic smile, the central incisors and lateral incisors should be in the range of 11-13mm
False- centrals 11-13mm and lateral 10mm
The preferred anatomical crown WIDTH to HEIGHT ratio is:
78%
(acceptable range= 66-80%)
The width of the central incisor should be ___% wider than the lateral incisors
60%
The width of the lateral incisor should be ___% wider than the mesial aspect of the canine
60%
If assigned a value of 1.0 to the lateral incisor, the central incisor would equal ____ and the mesial aspect of the canine would equal ____.
CI: 1.6x
Canine: 0.6x
List the gingival ZENITH for the following teeth:
centrals:
laterals:
canines:
centrals: 1mm distal to midline
laterals:0.3m distal to midline
canines: centered MD
The gingival margin of the central and canine should be:
on SAME line
The gingival margin of the lateral incisor should be:
0.5-1.0mm CORONAL to the central and canine
To help determine classification and treatment of a smile:
- Perform detailed smile analysis (axium)
- Look at amount and location of keratinized tissue
- Evaluate location of supporting bone (radiographs & or bone sounding)
- Understand where CEJ is located
- Understand the clinical vs. anatomic size of teeth (radiographs)
List the critera that must be met to diagnose altered passive eruption : (2)
- the tooth is short by measurement
- the CEJ cannot be detected in the sulcus with the tip of the explorer
Treatment goals for passive eruption:
- Thin and move alveolar bone 2mm apical to CEJ from facial line angle to facial line angle
- Position the gingival crest 3mm coronal to the new alveolar crest position
- Level the tissue at the new position
When surgically treating passive eruption, ____ incisions are used.
These incisions extend to ____ most of the time
sulcular; mesial of second molar
Give post-op instructions for crown lengthening:
- no brushing teeth for 4 days
- no brushing maxillary teeth for 2 weeks
- rinse 2x daily with antimicrobial rinse
- do NOT activate lower lip (kissing, straws, etc)
