PROS EXAM Flashcards
Describe kennedy class I
bilateral free end saddle
describe kennedy class II
unilateral free end saddle
describe kennedy class III
unilateral bounded saddle not crossing midline
describe kennedy class IV
bounded saddle crossing the midline
what must be present with a retentive clasp?
a reciprocal component i.e., chrome plate or clasp
what should a clasp be when seated?
passive
what are the dimensions required for a mid palatal bar?
bar width between 7 and 12mm
where can gingivally approaching clasps be placed on the tooth?
middle, mesial or distal
what are the different types of gingivally approaching clasps?
roach T/T clasp
I bar clasp
what materials can make clasps?
COCR
SS
GOLD
what design of clasp puts less stress on the tooth?
I bar
what design of clasps require an occlusal rest?
ring clasp
occlusally approaching circumferential clasp
three arm clasp
all made from COCR
why is a dental bar more hygienic?
frees up the gingival margins and lingual mucosa
what is a requirement for a dental bar?
no anterior spacing
what are the measurements for dental bars?
crown height of 9mm
bar width 5mm
2mm clearance from gingival margin
2mm clearance from incisal tip of tooth
what are the measurements for a lingual bar?
7mm from sulcus depth to gingival margin
3.5mm bar
3.5mm clearance from gingival margin
when may you want to use a lingual bar?
spaced anteriors
covers less gingival margins that a cocr plate
what can be added to a lingual bar for indirect retention?C
Cummer arms - resists posterior uplift
what is the role of an undercut gauge?
determines the amount of undercut an occlusally approaching clasp can engage
what undercut can cocr clasps engage?
0.25mm
what undercut can ss clasps engage?
0.5mm
what undercuts can gold clasps engage?
0.75mm
what are the properties of the clasp materials?
cocr - brittle
ss - more flex
gold - most flex
what are the 2 components of an occlusally approaching clasp?
flexible tip - below survey line
bracing - above survey line
what are the 3 types of articulators?
plane line
average value
semi adjustable with face bow
what is an average value articulator?
condyle angle set to an average 25-35 degrees
table set to an angle of 10 degrees
what is a facebow used for?
records relationship between maxilla and TMJ
what are the advantages of injection moulding over dough packing?
no flash - minimises open bite
no trial pack
less handling of material
less pressure when injecting material
what are the disadvantages of injection moulding over dough packing?
no need to add sprue
extra training
expensive
technique sensitive
difficult to deflask
what is flash?
the excess that comes out the side of the flask when dough packing
what does the thickness of flash result in?
thickness of denture
what do you do after injection moulding/ dough packing?
process
grind
polish
what may be seen with dough packing when denture is placed back on articulator?
pin wont touch table
what must a dough packed denture need done to it when fitting?
occlusal adjustment
what is contraction porosity caused by?
lack of pressure on acrylic resin - not enough resin to fill mould or failure to apply enough pressure when clamping flasks
what does contraction porosity look like?
small holes right through the denture
what is gaseous porosity caused by?
wrong curing cycle - too rapid heating when processing denture
where would you find gaseous porosity?
in the thickest part of the denture
what can happen if the alginate impression if left in the sterilising solution for too long?
imbibition
what can happen to the alginate impression if it is not kept in a sealed bag with wet napkins?
synerisis
what are the anatomical features of the upper denture bearing area?
labial sulcus
buccal sulcus
labial frenum
incisive papilla
palatine rugae
palatine raphe
buccal frenum
tuberosity
hamular notch
vibrating line
palatine foveae
what anatomical features are found in the lower denture bearing area?
labial sulcus
labial frenum
lingual frenum
buccal frenum
buccal sulcus
lingual sulcus
buccal shelf
retromolar pad
list the anatomy of the skull and surrounding muscles
medial pterygoid
buccinator
condyle
orbicularis oris
mental nerve
nasalis
coronoid process
masseter
temporalis
zygomaticus major
what is the fox’s guide plane used for?
determining a level occlusal plane
what is the willis bite gauge used for?
recording the occlusal vertical dimension
when may you decide to use flat cusped teeth?
when bite is not reproducible
what may a molloplast soft lining do to a denture?
weakens as there is less acrylic
what can you add to a denture with a molloplast soft lining to strengthen it?
wire strengtheners
what are the indications for rebasing a denture?
loose fitting denture
teeth are not worn and are in good condition
what must be done to a denture before taking the wash impression?
remove undercuts
what technique is used to take a wash impression?
closed bite technique
why do you use the closed bite technique for wash impressions?
avoids occlusal errors such as open bite and reduced thickness of material
what is the term used to describe the change in length of a specimen when testing dental materials?
elongate a specimen
what is the term that describes the hardness of a material?
force applied to a mid beam to fracture it
