Quiz 1 - Spring Flashcards
1557 carbide
Used for gross reduction and depth cuts, doesn’t heat up the tooth as much
170 carbide
Retention grooves, anti-rotational grooves
172 carbide
Retention grooves, refinement of isthmus and proximal boxes
1/4 round carbide
Pilot hole for pins, retentive slots and grooves
012 diamond
Breaking proximal contacts, light zirconia and Gold chamfer, light veneer preparations
77K-018 diamond
Heavy chamfer, limited access
78K-018 diamond
Most chamfers, occlusal refinement, this is the workhorse
016 diamond
All ceramic axial refinement, and rounded butt joint margin creation, also a workhorse
45KR-018 diamond
Posterior all-ceramic onlays, broader butt joint margins
023 diamond
Looks like an oval,
009 diamond
Tight spaces, rounding of line angles and point angles for all ceramic preparations
010 diamond
Beveled margin creation with Au partial coverage preparations, for interproximal area, only fine grit
Definition of a liner
Materials placed as a thin coating, usually less than 0.5 mm, on the surface of a cavity preparation
Liners are used for thermal insulation. True or False?
False. They are also not used to add bulk to a cavity preparation. Liners do not have sufficient hardness or strength to be used alone in a deep cavity
What are the five main types of liners?
- Varnishes
- Calcium Hydroxide
- Glass Ionomers
- Resins
- Resin-modified Glass Ionomers
What are the names of some varnishes?
Copalite, duraphat, dura-flor
What are the characteristics of calcium hydroxide?
Is basic, pH of 11, which inhibits bacterial growth and neutralizes acidic bacterial byproducts, is a pulpal irritant that stimulates the formation of reparative dentin, extracts growth factors from dentin matrix to produce dentin bridge
What are the names of some calcium hydroxide products?
Dycal, Life, TheraCal
What are the characteristics of glass ionomers?
Form ionic bond between carboxylates and calcium in the dentin and enamel
Provide sustained fluoride release to counter the effects of microleakage
Should not be used as pulp capping agents
Most common formulations are now in the form of resin-modified glass ionomers
Very moisture sensitive until set
What are the names of some glass ionomers?
Ketac bond, Fuji lining
What are the characteristics of resins?
High compressive strength
High tensile strength
Low solubility
Not recommended for direct pulp capping
What are the names of some resin-modified glass ionomers used as liners?
Vitrebond, Ketacbond, Fuji lining LC
What are the characteristics of bases?
Can be considered as restorative substitute for the dentin that was removed by caries and or the cavity prep
Are thicker than liners
Act as a barrier against chemical irritation, provide thermal insulation, resist the condensation forces on a tooth when placing a restoration
Can be shaped and contoured after placement into the cavity prep
Are often used to build out to ideal in preparation for either the direct or indirect restorative material
What are the main six types of bases?
- Reinforced zinc oxide and eugenol (IRM) (Don’t leave IRM under composite resin because it will soften it, and will also do so to acrylics, your temporaries. TempBond has eugenol and will do that)
- Zinc phosphate (Flecks) (Have to have good margins)
- Zinc polycarboxylate (A permament cement, might use on a temporary that is not very retentive, only way to get off is with ultrasonic scaler)
- Glass ionomer
- Resin (Compcore, Luxacore)
- Resin modified glass ionomer (Vitremer)
What are the purposes of build-ups?
Enhance connection of indirect restorative material to existing tooth structure
Permit creation of ideal retention and resistance form in crown preparation
Should help to direct occlusal forces axially
Eliminate undercuts to allow line of draw for indirect restoration
Reduce volume requirement of the indirect restorative material
When is a build-up necessary?
If over 1/2 of coronal tooth structure is missing
Pins and posts do not strengthen teeth. True or False?
True. They only enhance the connection. Posts tend to fracture roots, so teeth will last longer if you don’t have them, and just because tooth might have already had endo and pulp isn’t vital doesn’t mean that you have to use a post.
The definitive crown composition is more important than the crown preparation and ferrule. True or False?
False. Opposite
For best retention, posts should not be smooth, and the thinnest post with adequate strength is recommended. True or False?
True
What factor was found to have highest correlation to success of final restoration of endodontically treated teeth?
Remaining coronal tooth structure
Difference between cast posts and fiber posts and restorable roots after fracture?
Casts post have double the fracture strength value, but when they fracture the root, the root is unrestorable ALWAYS, but with prefabricated fiber posts, only 60% of the fractured roots are unrestorable.
What is the strongest crown material to cover an endodontically treated tooth with?
PFM, or metal
Definition of a ferrule?
Defined as from the crown margin up to where the dentin ends, sometimes you prep your crown subgingival to get a ferrule.
Best combination of posts and crowns for endodontically treated teeth?
Cast post and core with a PFM crown with a 2 mm ferrule
Where does most of the stress of the post take place?
Most of the stress of the post is at the apex near the bottom and that is where a fracture will start, and the posts that were shorter transferred more stress to the apex of the post, so a longer post distributed the stress more easily along the entire length of the post.
- Shear stress is usually directed at 135° degrees to long axis of tooth.
- Increased post length decreased shear stress at apical end of post.
What length of the root should a post be?
At least 2/3 to 3/4 the length of the root
Minimum amount of gutta percha left at apex for a post?
4 to 5 mm
What type of post will provide the most retentive post with the least stress?
Well-adapted, passively luted, parallel-sided post, serrated, tapered apical end
What type of post is not recommended?
Tapered self-threaded screws will cause stress fracture
How are dentin stresses reduced when placing a post?
- Bonding the dowel
- Increasing modulus of elasticity of the dowel
- Increasing diameter of the dowel
- Increasing length of the dowel
- Parallel sided dowels
(A dowel is a post)
What is the superior method of placement for most cements?
Lentulo spiral (but not with RelyX Unicem), the needle tube can also be used. And the most reliable results in fiber post cementation are obtained by etch and rinse adhesives, in combination with dual cure resin cements. Self adhesive cements have a lower bond strength than etch and rinse adhesives.