exam 2 (L11) - clinical crown lengthening Flashcards
define clinical crown lengthening (CCL).
a surgical procedure designed to increase the extent of supragingival tooth structure for restorative or esthetic purposes by apically positioning the gingival margin, removing supporting bone, or both
concepts of crown lengthening
- anterior esthetics:
+ gummy smile
+ gingival line symmetry
+ short front teeth - cervical caries or fracture lines
if pt has excessive gingival display, what is the indication and contraindication for CCL?
indicated: not enough of clinical crown displayed
- contraindicated: hypermobile lip, skeletal problem
at what measurement (from CEJ to FGM) can passive eruption cause an asymmetrical appearance of teeth?
> 2 mm
if patient presents with skeletal defect that causes an asymmetrical smile, what can be done to correct it?
oral surgery; do NOT do CCL
Please give a riveting laundry list of anterior aesthetic considerations.
- facial symmetry
- interpupillary line
- smile line: low, medium, high
- dental midline
- gingival display
- harmony of gingival margins
- gingival margins relative to CEJ
- tooth size/proportions
- incisal/occlusal plane
for lateral incisors, how much more coronal/incisal should the gingival margin be than for the adjacent centrals?
0.5 mm coronal/incisal
if deep caries or inadequate height are present before crown placement, how does CCL help?
- good crown margins
- good impressions with defined prep margins
- gingival health during provisionalization and after final restoration
- aids: adequate crown height, retention, and emergence profile
what is the biologic width from alveolar crest to CEJ?
- 2 mm (JE + CT)
- entire dentogingival complex (include sulcus) is 3 mm
what 2 problems will occur if biologic width is encroached upon during crown placement?
- gingival recession
- chronic inflammation
what is optimal distance from gingival margin to alveolar crest? from sound tooth structure (cavosurface margin) to alveolar crest?
- 3 mm
- at least 4 mm
what is “sounding” bone?
under local anesthesia, penetrate JE till you reach alveolar crest so you know pt’s BW
what are the 3 objectives of crown lengthening?
- maintain healthy dentogingival junction PDL
- improve esthetics
- improve access and retention for restoration
what are the 3 approaches to CCL?
- gingivectomy with no osseous surgery (external VS internal bevel)
- apically positioned flap with no osseous resection
- apically positioned flap with osseous resection
in what state does an externally beveled gingivectomy leave the gingiva? indications and contraindications?
- open wound that requires secondary intention healing
- indications = enough keratinized tissue, BW post-op
- contraindications = not enough keratinized, BW invasion
when should you do a gingivectomy for CCL?
- external: no bony involvement, remove excess KG
- internal: bony involvement/close to crest, remove excess KG
in what state does internally beveled gingivectomy leave the gingiva? indications and contraindications?
- wound can be closed to heal by primary intention
- indications = enough keratinized G, BW post-op
- contraindications = not enough KG, BW invasion
what are the two types of incisions for gingivectomy?
- externally beveled (simply for excess tissue)
- internally beveled (more conservative, bony involvement)
what are the 3 flap types available, when are they used, and what kind of incisions are available for use with them?
- modified Widman flap:
+ only fold slightly past the alveolar crest
+ cannot apically reposition gingiva
+ used for accessing roots for various procedures
+ has small incisions for SRP & curettage - partial thickness flap:
+ increase amount of keratinized tissue b/c it grows back bigger when periosteum is not exposed
+ can apically reposition gingiva
+ can use sulcular (coronal or reposition) or scalloped (palatal or apical positioning) - full thickness flap
+ used whenever you want to access bone
+ can use sulcular or scalloped incision
how well does apically positioned flap without osseous resection work?
it doesn’t, because the tissue will simply grow back if the bone remains in place (tissue rebound)
when is osseous resection performed concurrently with an apically positioned flap? what incision options do you have?
- when need to establish BW
- submarginal (scalloped) = when adequate KG present
- sulcular w/ apical position = when little KG
what is the golden proportion of esthetics?
- anterior teeth have a width:length ration of 0.8
- from frontal plane, W:L = 0.618
+ laterals narrower than centrals
+ canines narrower than laterals
+ canines > premolars
how long should you wait after crown lengthening to place the final crown?
at least 6 weeks
