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.
Never use a resin modified glass ionomer to cement a post. Just use a resin cement. True or False?
True
Delayed cementation of fiber post resulted in a lower retentive strength. True or False?
Opposite, you should wait at least 24 hours to get more retentive strength
The resin cement film thickness does not affect pullout strength of fiber reinforced posts. True or False?
False, it does, it should be large and fill the post space but not larger than 0.3 mm.
In oversized canals, bonding the post with the core build-up material is probaby indicated. True or False?
True. But this is the only occasion for this.
Self-adhesive resin cements have a higher bond strength than the self-etching resin cement. True or False?
True
The three conditions most important for longer term success of post-endodontic restorations are:
- Preservation of tooth tissue
- Ferrule effect
- Adhesion
The most common type of failure when using fiber posts is?
Post debonding, it is harder to bond to intraradicular dentin than coronal dentin
What are the three types of pins?
- Cemented
- Friction Locked
- Threaded
What are the instructions for placing pins?
Place at line angles
Place 0.5 to 1.0 mm inside of DEJ (1/4 round pilot hole)
Hand placement only, don’t drive in with slow speed motor
You can bend pin if you need to be contained within core of build-up
1/4 round pilot hole
Slow speed go halfway, drill out, finish the rest
What are the steps for placing a post?
- Gates glidden #2 or #3
- Keep minimum of 5 mm of gutta percha to maintain apical seal
- Confirm with radiograph if necessary
- Allow drill to follow path of least resistance
IF NECESSARY, REMOVE ADDITIONAL TOOTH STRUCTURE IN ORDER TO CONSTRUCT A STRONGER POST. True or False?
False, DO NOT.
THE THINNEST POST WITH ADEQUATE STRENGTH WAS RECOMMENDED. True or False?
True
FOR BEST RETENTION, IT WAS FOUND THAT POST SURFACES SHOULD NOT BE ROUGH. True or False?
FALSE, SHOULD BE SMOOTH
REMAINING CORONAL TOOTH STRUCTURE WAS FOUND TO HAVE THE HIGHEST CORRELATION IN REGARD TO SUCCESS OF THE FINAL RESTORATION OF ENDODONTICALLY TREATED TEETH. True or False?
True
What is the ideal facial depth at margin for a zirconia anterior all ceramic crown preparation?
0.5-1.0 mm
What is the ideal lingual depth at margin for a zirconia anterior all ceramic crown preparation?
0.5-1.0 mm
What is the lingual concavity depth for a zirconia anterior all ceramic crown preparation?
1.0-1.5 mm
What is the ideal incisal reduction depth for a zirconia anterior all ceramic crown preparation?
2.0-2.5 mm
What is the ideal facial depth at margin for a lithium disilicate anterior all ceramic crown preparation?
1.0-1.2 mm
What is the ideal lingual depth at margin for a lithium disilicate anterior all ceramic crown preparation?
1.0-1.2 mm
What is the ideal lingual concavity depth for a lithium disilicate anterior all ceramic crown preparation?
1.5-1.7 mm
What is the ideal incisal reduction depth for a lithium disilicate anterior all ceramic crown preparation?
2.0-2.5 mm
What is the diameter of the 016 diamond bur near the shank?
1.5 mm, it is 1 mm at the tip, and 1.25 mm half way
What is the composition of silicate cement?
Silicate glass and phosphoric acid
What is the composition of glass ionomer cement?
Silicate glass and polyacrylic acid
What is the composition of ZOE?
Zinc Oxide and Eugenol
What is the composition of Zinc Phosphate?
Zinc Oxide and Phosphoric Acid
What is the composition of Zinc Polycarboxylate?
Zinc Oxide and Polyacrylic Acid
What is the composition of IRM?
ZOE + Acrylic Powder + Eugenol (IRM is also called Reinforced ZOE)
What is the composition of EBA cement?
ZOE + Al2O3 + Eugenol + EthoxyBenzoic Acid
What are the characteristics of EBA cement?
This is a permanent cement, and they recommend it only be used where mechanical retention is high. It is fairly soluble. Endodontists have used this for doing apicoectomies. Along with MTA, which is the best for this.
What are the main six permanent cements?
- Zinc polycarboxylate
- Zinc phosphate
- Glass ionomer
- Resin
- RMGI
- Polyurethane (Improv) - for implants
What is film thickness?
A measure of viscosity. Is an issue with powder/liquid formulations. NO powder remnants in mix. You want around 25 micrometers and 1 inch snap off.
What are the characteristics of polycarboxylate (Tylok, Durelon)?
Kind to the pulp
Quite soluble
Good intermediate strength
Inexpensive cement
Not technique sensitive
Acidic
Weak chelation bonds to calcium ions of enamel and dentin
Not recommended for “permanent” use anymore
Unlimited shelf life, low cost, ease of use
What are the characteristics of Zinc phosphate (Fleck’s)?
Long history, has been standard Great compressive strength Very hard and time consuming to mix Very technique sensitive Early acidity can be irritating to pulp Moderate solubility when mixed properly High solubility when mixed poorly Not widely used anymore Mix on cold glass slab to slow exothermic reaction, and in increments to control set and allow for adequate amount of powder
What is the difference between Fuji and FujiCEM?
Fuji is a glass ionomer luting, liner, filler, or buildup.
FujiCEM is a RMGI luting agent.
We use FujiCEM 2 and Fuji IX in clinic
What is vitrebond?
It is a RMGI liner
What is Ketac?
There are several, and there are plain glass ionomer buildup material, fillers, or luting (CEM) agents
What are the characteristics of Glass ionomers?
Sustained fluoride release Less soluble than zinc phosphate Much more soluble than resins Weak dentin bond (3-7 MPa) Tooth sensitivity (low molecular weight acid penetrates dentinal tubules Keep tooth moist, even wet, prior to cementation DO NOT over-dry! They expand after set due to moisture
What are the three cement materials that form a bond with tooth structure?
Ketac Cem Plus (weak dentin bond) and Zinc Polycarboxylate (weak chelation bonds to calcium ions of enamel and dentin) and Self-adhesive resin cements (weak bond as well). The first two both have polyacrylic acid as a component of their composition. Ketac Cem Plus has silicate glass and is a GI, and Zinc Polycarboxylate has zinc oxide as well.
What is the composition of resin cements?
Diacrylate resin
Silica or glass filler
Acidic adhesive (self-adhesive only has this)
What are the three types of diacrylate resin?
- Acrylic Acid
- Bis-GMA
- UDMA
What is an acrylic?
A synthetic resin made of polymers of acrylic acid or acrylates
What are the three types of resin cements?
- Adhesive
- Self-adhesive (RelyX Unicem)
- Esthetic
What are the characteristics of adhesive resin cements?
Usually chemical cure
Limited shades
Bonds to many surfaces
Strongest of bonds
Good under metal or other opaque material
Suitable for posts, over-tapered, short, or unretentive crowns
Very technique sensitive, 10 minute set
Remove excess cement during rubbery phase
What are examples of adhesive resin cements?
C&B Metabond
Panavia
C&B Cement
What are the characteristics of self-adhesive resin cements?
Phosphoric acid grafted into resin
Neutralized as resin sets
No need for etching, conditioning or priming surfaces to be bonded
Good, intermediate bond strength
Not recommended for veneers or feldspathic porcelain bonding
Convenient and easy to use
Most bond better to dentin than enamel
Suitable for gold crowns, inlays, onlays, PFM, high strength ceramic crowns, posts, FPD
When light activated, flexural strength and elastic modulus are higher than when only self cured
Are associated with less post-cementation sensitivity than traditional crown and bridge cements
Exhibit a low incidence of marginal staining
What are some examples of self-adhesive resin cements?
RelyX Unicem
Maxcem Elite
BisCem
SpeedCem
What are the two cements we will use the most in clinic and what are their differences?
RelyX Unicem (self-adhesive resin cement) and FujiCem (glass ionomer cement) RelyX Unicem along with FujiCem is great for cementing crowns, you won’t have sensitivity as long as you don’t dry the tooth. Even though FujiCem has the name Cem behind it, it is a resin modified glass ionomer so you can’t use it with a post, like you can this stuff, because it will expand
What are the characteristics of esthetic resin cements?
Use with separate bonding agent
Tooth enamel is etched with phosphoric acid in preparation for bonding
Can be light cured or dual cured
Use light activation whenever possible - dual cured cements typically have increased flexural strength and bond strength when activated with a light
Wide variety of shades, including try-in pastes
Translucent shades may be sensitive to ambient light
Very strong bond, especially to enamel
Suitable for veneers, lithium disilicate (e.max), translucent zirconia crowns
What is a catalyst?
Catalysts are used and mixed in when you might have a thicker prostheses and you can’t get a light cure all the way through, but catalysts will make a darker shade around the area, which isn’t ideal.
What are some examples of esthetic resin cements?
Calibra
RelyX ARC
Variolink II
Steps to bond a veneer?
VERIFY FIT OF VENEER
• IF CONTAMINATED WITH WATER, RINSE AND AIR DRY
• IF CONTAMINATED WITH SALIVA &/OR BLOOD, RE-ETCH INTAGLIO SURFACE WITH PHOSPHORIC ACID FOR 30 SECONDS
• THOROUGHLY RINSE WITH WATER
• AIR DRY
• APPLY SILANE TO INTAGLIO SURFACE OF VENEER
• AIR DRY
PHOSPHORIC ACID ETCH ENAMEL FOR 15 SECONDS
• THOROUGH RINSE
• AIR DRY (DO NOT DESICCATE!)
• APPLY 2 COATS OF GLUMA OR MICROPRIME (WAIT 60 SECONDS)
• AIR DRY (DO NOT DESICCATE!)
• MIX AND APPLY PHOTOBOND (DO NOT LIGHT-CURE YET!)
• AIR THIN
• APPLY BASE SHADE (Calibra) ONLY TO VENEER (NO CATALYST)
• PLACE VENEER
• REMOVE EXCESS, INCLUDING FLOSSING INTERPORXIMALLY
• TACK CURE
• REMOVE EXCESS CURED RESIN
• FINAL CURE
What are the names of the two main RMGI cement that we have in the clinic?
RelyX Luting Plus and FujiCem 2
What type of restoration are RMGI cements suitable and not suitable for?
Gold crowns, onlays, lithium disilicate crowns, zirconia, PFM, FPD’s, but NOT suitable for posts or inlays because of expansion.
What are the three types of main temporary cements?
- Eugenol based (Temp-Bond)
- Non-eugenol based (Zone)
- Resin based
What does eugenol do to acrylics?
It can soften them
What is a resin based temporary cement used for?
Good to use if temporizing for a long time. And cleans up nicely, especially from implants. -Kind of an intermediate, not as strong as a flowable, but stronger than these other cements, but one downside to this is that it does bond to a build-up made of resin. Improv is a polyurethane resin based temporary cement.
A FERRULE IS MORE IMPORTANT IN CUSTOM CAST POST CORE THAN IN PREFABRICATED POST AND COMPOSITE CORE. True or False?
True
Which of the following does not have a critical effect on the levels of stress in the dentin:
1) Ferrule effect
2) Stiffness of the post material
3) Post length
Post length
The length of the post has a significant effect on its retention. True or False?
True. Posts that are 3/4s the length of the root offered the greatest rigidity and least root deflection (bending)
Which posts produce the greatest stress at the coronal shoulder?
Tapered posts
Where do parallel posts produce their greatest stress?
Apex of the canal preparation