saddles, connectors and retainers Flashcards
the part of the p denture which carries the artificial teeth and replaces lost tissue
saddle
abutment teeth at either end of the saddle
bounded saddle
single abutment tooth at mesial end of the saddle
free end saddle
a tooth which the loss of will convert a bounded saddle into a free end saddle
critical abutment tooth
kennedy class 1
bilateral free end saddle
kennedy class 2
unilateral free end saddle
kennedy class 3
single bounded saddle not crossing midline
kennedy class 4
single bounded saddle which crosses midline
a part of a p denture which unites other components
connector
types of connectors
major and minor
major connector role
unites p denture saddles
provides bracing
provides indirect retention
acts as splint
materials for major connectors upper p
PMMA
gold
CoCr
types of connectors for lower partial dentures
lingual plate
CoCr lingual plate
dental bar
lingual bar
split lingual bar
split lingual plate
when would you use a split lingual plate
insufficient sulcus depth
what type of partial denture could you prescribe if retention/ stability is compromised?
swinglock
what type of p denture could you prescribe to someone who has just has oral cancer surgery?
swing lock
major connectors for upper p dentures
PMMA plate
Co/Cr base plate
shapes of palatal plates for single tooth
spoon
T
types of connectors for kennedy class 2
horseshoe connector (ant pal bar)
mid palatal bar
posterior pal bar
what risks come with a sectional maxillary denture
inhalation
the connecting component between the major connector or base of a p denture and other units such as clasps and rests
minor connector
when may you need to modify a base
if lower teeth occlude onto upper ridge
what modifications can you add to a base
CoCr striking plate
how are dentures retained
physical forces from saliva between denture base and mucous membrane
muscle activity of lips cheeks and tongue
when would you prescribe a spoon denture
temporarily post xLA
Partial denture retention
clasps
objects of surveying
determine path of insertion
assess teeth and tissue undercuts for retention
determine depth of undercuts for clasps
what is used to check for presence of and location of undercut during surveying
analysing rod
what is used to mark the survey line and hence the position of the undercut during surveying
marking rod
what is used to measure the depth of undercut when surveying
undercut gauge
types of clasps
occlusally approaching
gingivally approaching
what type of clasp is more rigid and efficient at bracing
occlusally apporaching
what type of clasp is less caries susceptible
gingivally approaching
types of gingivally approaching clasps
T roach
what does it mean when a clasp is passive when seated
puts no force on tooth
when must a clasp flex
to pass the bulbosity
what is reciprocation
a suitable element provided to the other side to act as a balance to counteract force
providing resistance to lateral/ horizontal forces on the denture
bracing
what type of clasp could be used for pts with no undercut
ball ended clasp - engages undercut in interproximal area
what type of clasp provides retention and bracing
ring clasp
materials for clasps
Cast CoCr
Wrought stainless steel
Gold
Thermoplastic copolymer - dental D
what undercut does cast CoCr clasps engage
up to 0.25mm
what undercut depth does ss clasps angage
up to 0.5mm
what undercut depth do gold clasps engage
up to 0.75mm
what undercut depth do thermoplastic copolymer clasps engage
deep undercuts
what are types of tooth prep?
addition of composite
grinding
crown placement
prep to alter survey line
when would you grind tooth prep
allow call ended clasp engagement
when would you add crown placement
provide undercuts
when would you add composite for tooth prep
provide retention
what type of clasp would you use if the undercut is lingual
ring clasp
what type of clasp would you use if undercut close to gingival margin
gingivally approaching
when can you not use CoCr clasp and why
if undercut more than 0.25mm as too much force is required
what are guide planes
making surface at either end of saddle area parallel to limit path of insertion to improve stability
RPI system
r - mesial rest
p - distal guiding plate
i - I-shaped retentive clasp i.e. I bar
when would you use the RPI system
free end saddle
why is an RPI system used
reduces stress on abutment tooth
what is lock and key
one part on tooth (in crown or inlay) and other in denture - slots in
