Crown Lengthening Flashcards
what are the indications for functional crown lengthening
- subgingival restorative margins
- tooth fracture
- endodontic perforations
- cervical root resorption
what are the indications for esthetic crown lengthening
- excessive gingival display
- gingival overgrowth (from medications)
- altered passive eruption
what is the supracrestal attachment number
2.04mm
what is the supracrestal attachment made of
- CT: average of 1.07mm
- junctional epithelium: 0.97mm
which part of the supracrestal attachment is more variable
the JE
what are the indications for crown lengthening
- to allow for restoration of tooth (caries removal, clamp placement)
- increasing crown length for retention of restoration (adequate ferrule)
- restoration of tooth in harmony with supracrestal attached tissue (biologic width)
- esthetics via alteration of the gingival labial profile
what is a ferrule
the vertical axial wall that surrounds the tooth
when is the ferrule needed
every time a crown is fabricated to help resist fracture and/or crown displacement
how much ferrule do you need
at least 2mm of ferrule (natural tooth structure) circumferentially, beyond the core
what are the considerations and limitations for crown lengthening
- is the tooth restorable
- is the tooth strategically important
- prognosis
what is considered in if the tooth is restorable
caries removal is done
what is considered in “is the tooth strategically important”
- opposing tooth
- position in the arch
what is considered in the prognosis of crown lengthening
- amount of tooth remaining in supporting bone
- furcations
- mobility
- esthetic concerns
- thick or thin phenotype
when are the caries removed and when is the provisional crown done in relation to crown lengthening
before surgery
when is the final restoration placed after crown lengthening
variations between 6 weeks and 6 months but not sooner than that
if you are in doubt how long should you provisionalize the tooth after crown lengthening
3-6 months
in health the CEJ should be _____ from osseous crest
2mm
in health the gingival margin should be _____ coronal to the CEJ
0.5-2mm
describe active eruption
- as the tooth breaks through the gingiva it erupts until it meets its antagonist and occlusion
- eruption then ceases or slows
- eruption potential continues throughout life
what is passive eruption
apical shift of the dentogingival junction
- occurs during and after active eruption
- tooth does not move, gingiva does (apically)
what are the stages of passive eruption
- junctional epithelium rests on enamel surface
- JE rests on enamel and cemental surface apical to CEJ
- epithelial attachment rests on cementum
- epithelial attachment migrates apically
when does passive eruption conclude
when sulcus base is at level of the CEJ placing the gingival margin 1-2mm coronal to the CEJ
what is altered active eruption and what is it exacerbated by
- morphological variant where CEJ is less than 2mm from osseous crest
- can be exacerbated by orthodontic brackets
what is altered passive eruption and what is it exacerbated by
- morphological variant where gingiva is more than 2mm coronal to the CEJ
- can be exacerbated by inflammation and medications