where do tapered posts transfer stress to teeth?
where do parallel posts transfer stress to teeth?
a cast, post, and core is indicated on a tooth with how much of the coronal tooth structure missing?
more than 1/2
would you ever do a prefabricated post if you have less than 1/4 coronal tooth structure left?
what affect does texture of the intaglio surface have on retention?
roughened intaglio surface improves retention
what affect does a roughened tooth preparation have on retention?
is it critical for the arches to be parallel when using a monotrack articulator? what angle do you NOT want the arches to be and why?
- you don't want the arches to converge because it makes it harder to trim and harder to index
- better to have the arches diverge
cuspal fractures are more common in what type of restoration?
uncommon with indirect gold onlays
what are the symptoms of fractured tooth syndrome? what is the caveat?
- cold and pressure sensitivity
- inconsistency with symptoms if the caveat
where can cracks form as a result of a direct filling?
at the base of the isthmus or box, mostly at 45 degree angles but that can vary
T or F:
incomplete cracks will show symptoms on bite and release, as well as heat sensitivity
they WILL show symptoms on bite and release (pressure), but are cold sensitive (NOT hot)
how can you clinically test if a tooth has a crack?
- use a tooth sleuth to test each cusp
- if one cusp produces pain but the others don't, you know you have a crack
how should you use a tooth sleuth to test for cracks?
- you want to start on a tooth that is somewhat far away from the tooth that the patient indicates is causing them pain, then get progressively closer to the offending tooth
- place the tooth sleuth on the cusp of the tooth you are testing, have the patient bite and release, and record the patients response
what is the treatment for a fracture or incomplete fracture?
some kind of coverage, typically a crown, but it does not need to be completed right away - depends on patient preference, finances, and whether or not it is bothering the patient
fractured teeth are not always consistent in terms of symptoms. what can inconsistency be related to?
can be related to occlusion
what can you do if there are occlusion problems relating to inconsistency of symptoms of a fractured tooth?
you can adjust the bite and take the tooth out of occlusion to alleviate symptoms until treatment can be performed, but you must inform the patient of what you are doing, and that it is only a temporary fix
what cusps are fractures more common on?
non-functional cusps (maxillary buccal cusps and mandibular lingual cusps)
what is the treatment for a crack that is in the enamel only or is very shallow in the dentin and is asymptomatic?
you may not have to do any treatment at all
once you start the process where you've invested your wax pattern, put it in the oven, wax is burned out and you start the casting process, can you interrupt that (cool down the mold and reheat it)?
no because the material breaks down
what affect does palladium have on the color of gold?
it turns it into white gold
what does copper do to the color of gold?
makes it more yellow
with a broken arm casting machine, why do we have to place the margins of the wax pattern to the right (clockwise)?
the flow of material is in a clockwise direction and it throws the material towards the margins
when an exising crown comes off of a tooth, it fails. where is the most common failure interface?
intaglio surface of the crown-cement interface
what are the 3 types of resin cements?
- self adhesive
what is the name of the self adhesive resin cement used at the UUSOD?
how does self adhesive resin cement set?
chemically (on its own)
what does light curing do to self-adhesive resin cement?
even though self-adhesive resin cement sets chemically, light enhances the polymerization linkage, with increases the compressive strength
what are the two most important properties of cements, and what is the benefit of these properties?
- increased compressive strength
- increased elastic modulus
- these properties improve the ability of indirect restorations to stay on the tooth
what is the purpose of die spacer?
- creates a space for the luting/bonding agent
- helps eliminate some of the error points in the occlusal surface
what are the most common permanent tooth that is lost first?
mandibular first molars, partly because they are the first to erupt