9/12 - Surveyed Crowns Flashcards
why is it called “surveyed” crowns
because we use the surveyor to make these crowns
when does one choose to fabricate a crown to serve as RPD abutment
- enamel modification
- dentin exposure
- restore clinical crown, occlusal, plane, provide rests, etc.
surveyed crown is created when correction of unacceptable tooth contours cannot be achieved thru ___
enamel modification
surveyed crown is created when correction of unacceptable tooth contours can lead to dentin exposure making and abutment tooth susceptible to ___ and ___
sensitivity and caries
can you resposition the occlusal plane with surveyed crown? example?
YES - e.g., supraerupted teeth
surveyed crowns can be used to provide proper rests, particulary with what?
anterior teeth and retentive undercuts
kratochvil vs. krol
Kratochvil:
- length of tooth guide planes
- 2-3 mm tissue coverage high polish
Krol
- guide planes: 2-3 mm
- 2-3 mm tissue coverage
what is the greatest point of convexity while surveyed
HOC
where are retainers placed
2/3rds above HOC or 1/3 below HOC
what burs to use for cingulum rests?
inverted diamon, 876, or 1172
where are cingulum rests placed
anterior teeth
you must be careful to not do what when creating cingulum rest
careful of creating undercut
T/F: cingulum should be touched when creating cingulum rest
FALSE! do not touch cingulum to maintain positivity
cingulum rests are concave from ___ view and convex from ___
mesial/distal; lingual
cingulum rests should be low or high on the tooth from the mesial/distal view?
low
when is surveyed crown needed
- broken-down tooth is critical abutment tooth for PRDP
- abutment tooth cannot be altered to provide desired contours (support, stability, retention)
- occlusal plane discrepancy needs to be corrected
sequence of creating partial
- diagnosis
- design
- fixed restoration
- removable restoration
what is done during appointment 1
diagnostic impressions
what is done between appt 1 and 2
- draw design
- prep cast
- custom tray
what is done during appt 2
- tooth prep
- final impression
- index accuracy
what is done between appt 2 and 3
- master cast readied
- work authorization
what is done during appointment 3
framework try-in
what is done during appt 3 and 4
record base fabrication
what is done during apointment 4
- records
- altered cast
- tooth selection
what is done btwn appt 4 and 5
articulate and set teeth
what is done during appointment 5
tooth tryy in
what is done during appointment 5 and 6
esthetic wax up
what is done during appointment 6
checks (24 hour and 1 week)
how should diagnostic casts be articulated? what is mostly used downstairs?
centric relation or max intercuspation
mostly use MI in clinic
surveyed crown fabrications (this is long)
- articulate diagnostic casts
- surveye diagnostic wax up with appropriate design features
- duplicate diagnostic wax up for stone cast
- preparation guides fabricated
- prepare and provisionalize abutment
- final full arch impression
- records accordingly
- survey full contoured wax up with design principles
- wax cut back of metal or metal ceramic
- cast, fit to die, metal try in to verify fit of casting, occlusion if applciable
- ceramic bisque survery try in
- glaze and final cementation
- refinement of other PRDP abutments and final impression
- finish PRDP in traditional manner
do you send the whole pindex to lab
yes and they send the whole thing back to you when they make the crown for you to check
aPpARrantLY
advantages of using survey crown
- easier to do guide planes, rests, etc.
- hard to see angle and undercuts on natural teeth
surveyed crown path of insertion should match what
insertion path of RPD (for the most part)
you should be cautious of using surveyed crowns on what teeth? why?
- endodontically treated teeth
- teeth w/ post restorations
because will likely lose teeth
extra reduction is needed in areas of rests, clasps, or guide planes for NATURAL TEETH or SURVEYED CROWNSS?
surveyed crown
what is the panograph used with
articulator for records
guy in picture looked like –▭–▭–
do you have to get wax up signed off
yes
if patient has existing RDP and survey crown breaks, what do you do? what is easier
- attempt to make a new survey crown
- EASIER: make new RDP after making new crown
what are the ways you can attempt to fix survey crown with an existing RDP
- make impression w/ partial in place, syringe around tooth and make impression, partial remains in impression. make another impression without partial. both impressions with RPD and without are sent to lab. adjust and cement crown and hope it fits
OR
- place GC pattern impression coping directly made on tooth over prep and inbetween the partial. send the pattern resin to lab and they include this into their wax up. this requires a lot of adjustments and sometimes doesn’t work
