RP - surveying and design Flashcards
what is used to analyse tooth and tissue undercuts and determine the path of insertion?
analysing rod
what is used to scribe tooth and tissue undercuts on the model with the graphite marker?
graphite marker
what is used to measure the desired amount of undercut for the clasp material used?
undercut gauge
what is used to trim the blocked out undercut areas on the model?
chisel
what information is gained from the survey line?
indicates the undercut area on tooth and non undercut area
the type of survey line indicated what retentive component can be used to help retain the denture
what type of clasp would be used for a diagonal survey line?
occlusally approaching clasp
(ss or cocr)
what type of clasp would be used for a high survey line?
gingivally approaching clasp
what type of clasp would be used for a low survey line?
gingivally approaching clasp - mesial, central or distal positioned.
what material of clasp is used for an undercut of up to 0.25mm?
cocr (brittle)
what material of clasp is used for an undercut of up to 0.5mm?
ss (more flexible, so can engage deeper undercut)
what material of clasp is used for an undercut of up to 0.75mm?
gold - most flexible
what are the 2 parts of a clasp?
bracing area
flexible tip
what are the 3 functions of occlusal rests?
provide support
direct occlusal loads down long axis of tooth
provide indirect retention
how thin is a cocr plate?
0.5mm
how thick is PMMA for a denture base?
1.5-2mm
how much space is required from the sulcus depth to the gingival margin to prescribe a lingual bar?
7mm
allows for 3.5mm bar width and 3.5mm clearance from gingival margin
how thick should a lingual bar be?
3.5mm
what can be added to a lingual bar to add indirect retention?
cummer arms
when is it a good idea to prescribe a lingual bar?
spaced anteriors
how much crown height is required for a dental bar?
9mm
bar width 5mm
2mm clearance from gingival margin
2mm clearance from incisal tip
what is more hygienic? lingual bar or dental bar?
dental bar - frees up the gingival margins and lingual mucosa
list the different designs of clasps used to retain dentures?
- cocr ring clasp with occlusal rest
- occlusally approaching circumferential clasp, cocr with occlusal rest
- 3 arm clasp cocr with occlusal rest
- ss occlusally approaching
- gold gingivally approaching clasp
- dental.d.acetyl resin clasp
advantages of dental.d.acetyl resin clasps?
very flexible
can engage deeper undercuts than metal clasps
available in tooth shades
what are the variations of gingivally approaching clasps?
roach T or T clasp
I bar clasp
what are the dimension requirements for a mid palatal bar, posterior bar or anterior bar?
bar width 7-12mm
