Last trimester recap Flashcards
(18 cards)
What are the consequences of tooth loss?
Reduced facial height
Compromised aesthetics
Partial or complete loss of function
Extrusion can lead to ectopic caries
Bone resorption leads to lose of lip support
Costly and some can be challenging to replace
Front teeth can flare if posterior bite collapses
Collapse dental arch or occlusion
What is a kennedy Class I?
Bilateral edentulous areas located posterior to the remaining natural teeth
What is a kennedy Class II?
Unilateral edentulous area located posterior to remaining natural teeth
What is a kennedy Class III?
unilateral edentulous area with natural teeth remaining anterior and posterior to it
What is a kennedy Class IV?
Single but bilateral (crosses midline) edentulous area located anterior to remaining natural teeth
what is required on a patient form?
patient name
record number
DOB
gender
clinical details
clinician name
contact details
type of restoration
shade
prescription date
due date (including next appointment) items included in prescription (impressions, models, bite registrations)
what are the components of an RPD?
saddle
major connectors
minor connectors
rests
direct retainers
stabilizing components
indirect retainers
denture base
what are advantages of gypsum bonded investment?
easy to divest
easy sandblasting due to low oxide adhesion
expansion controlled by changing liquid proportion
high cristobalite content produces smooth surfaces
What are phosphate bonded investment materials?
quartz, cristobalite, MgO (magnesium oxide), ammonium dihydrogen phosphate are homogenously mixed.
Silica sol is mainly used as the investment liquid to increase crystallisation effect and expansion.
what are some advantages of phosphate bonded investment materials?
suitable for any material and technique
broad expansion range control
high precision
longer shelf life
what are some disadvantages of phosphate bonded investment materials?
harder and relatively difficult to divest and sandblast due to strong adhesion and oxide formation
sensitive to light and heat
what is induction melting?
harnesses the power of electromagnetism to heat conductive metals and uses a high density electric current to pass through the copper coils to produce a magnetic field around the crucible.
what is hygroscopic expansion?
when investment material is set in the presence of water, such as immersing it in water during the setting time.
this increases the expansion of the investment material
what is setting expansion?
the expansion that occurs as investment material sets after mixing.
occurs due to crystallisation process from a liquid to a solid crystalline form.
amount of setting expansion can be manipulated with liquid-to-powder ratio
what is wax-pattern expansion?
when the investment material is liquid, the wax is heated above the temperature that it was formed.
increase in dimensions of wax-pattern when submerged in investment material and subjected to heat allows for compensation of shrinkage that occurs in metal alloys
what is thermal expansion?
occurs during burning out, due to investment material being heated.
when it is heated, the material expands due to increased molecular motion
quartz and cristobalite have different expanding rates depending on temperature, the combination allows for controlled and gradual expansion
how does the centrifugal induction casting system work?
once melt is molten, the ring is placed in the rotating arm of the system. the lever is pushed which causes the casting arm to spin rapidly produces centrifugal force that drives molten metal out of the crucible into the mould.
how does a vacuum-pressure induction system work?
the vacuum chamber is filled with gas to reduce exposure to oxygen.
once metal is molten, pressure pushes the molten metal to flow into the mould.
