Clinical Management Flashcards
What are the five clinic requirements
signed treatment plan (blue) phase 2 completed treatment form complex treatment (green sheet) surveyed diagnostic cast custom tray if necessary
Addition silicone and polyether remained accurate after how much time (and can be poured repeatedly)
1 week
What are the two major requirements of a framework impression
records the anatomic form on the teeth
records the moving tissues that will border the denture in an unstrained position
What could result if there is under extension of the impression
food impaction
inadequate contours
What could result if there is over extension of the impression
sore spots
over contoured or overextended areas
What are two major requirements of impression materials
must record tooth and tissue detail accurately
can be withdrawn from tooth and tissue undercuts without permanent deformation
What are the primary stress bearing areas of the maxillary arch
posterior alveolar ridges
hard palate
What is the secondary stress bearing area of the maxillary arch
anterior alveolar ridges
What are the primary stress bearing areas of the mandibular arch
buccal shelf
retromolar pad
What is the secondary stress bearing area of the mandibular arch
alveolar ridge
What are the four indications for a stock tray with alginate
Kennedy III (tooth supported)
mandibular kennedy I or II
when a secondary impression will be used and the alveolar ridges exhibit adequate support
The altered cast impression is dependent on what for a portion of its support
residual ridge
How does an altered cast impression obtain retention
from its base aided by indirect retention to precent the dentures lifting away from the residual ridge
What are three indications for a custom tray
kennedy class I or II mandibular arch with severe ridge resorption all maxillary kennedy class I or II RPDs when modification to a stock tray is not possible
This occurs during the setting of elastomeric materials which is proportional to the thickness of the material
dimensional changes
Dimensiontal changes are minimized when the thickness was a consistent what
2-3mm
These two things directly relate to the distortion of the impression
thickness of the impression
size of the undercut
Which causes greater distortion, increased thickness in the impression or increased size of the undercut
increased thickness
What are the measurements of custom tray fabrication
1-1.5mm short of the vestibule
2mm wax spacer over teeth
1mm wax spacer of edentulous areas
What are two advantages of irreversible hydrocolloid (alginate)
cost
simplicity
What are two disadvantages of alginate
must be poured within 15 minutes
border control is difficult
Which areas of the maxillary arch are typically modified
palate
posterior border
tuberosity
Which areas of the mandible are typically modified
lingual flange
retromolar pad
Why would you modify a stock tray
alginate is more accurate at a thickness of approximately 5mm
in an area such as a deep palatal vault or edentulous area there will be more than 5mm of space for alginate
What are five precautions involving irreversible hydrocolloid
impression must be held immobile during gelation
remove impression from mouth quickly in long axis of teeth
impressions should not be immersed in water
impressions should be protected from dehydration
impression must be poured within 15 minutes
What are three precautions of using alginate in terms of pouring casts
measuring the powder and liquid
vacuum spatulation
use type IV dental stone (pink stone)
This has better border control than alginate in an adequate supporting tray
polysulfide
What are some advantages of polysulfide
low cost
flexible
high tear resistance
long working time
polysulfide has the highest what of elastomeric materials
flow
What are four disadvantages of polysulfide
messy
must be poured within one hour
longer setting time = more chair time
custom tray recommended
What are four advantages of polyvinyl
automixing cartridges
dimensional stability
highly accurate
shorter setting time than polysulfide
What property is polyvinyl excellent at
recovery from deformation on removal
What are four disadvantages of polyvinyl
cost
increased rigidity
lower tear strength
custom tray recommended
What is it that about the increased rigidity of polyvinyl that makes it hard to work with
does not flow well
more difficult to remove from undercuts
more difficult to separate casts
What are five advantages of polyether
short setting time highly accurate dimensionally stable hydrophobic automix cartridges available
What are six disadvantages of polyether
low flexibility extremely rigid low flow cost low tear strength custom tray recommended has limited use in RPDs
What is the most flexible impression material, which would work well with tall teeth and big embrasure spaces
polysulfide > polyvinyl > polyether
What impression material has the best elastic recovery from deformation
polyvinyl > polyether > polysulfide
It is important to block out the pontic area of FPDs with wax for which impression materials
polyvinyl and especially polyether
What are five possible causes on an inaccurate cast
inaccurate water:powder ratio improper mixing of stone trapping of air separation of cast too soon failure to separate the cast for an extended period of time
What are some things regarding the economics of choosing an impression material
alginate is stupid cheap - 30 cents/impression
while the others range from $60-$10/impression
What could be used to increase the patients tolerance of an impression material
topical anesthetic