Op 2 - Veneer Prep and Design Flashcards
What are the 3 indications for veneers?
Shape modification
Color modification
Space closure (diastema/peg lateral, < 2 mm of space)
What are the contraindications for veneers?
Bruxism (limited occlusal clearance)
Not enough remaining tooth structure
What is the 1st critical step in managing pt expectations for veneers?
Diagnostic wax up
What is necessary to validate occlusal schemes and define pt specific limitations?
Diagnostic wax up
What is the 2nd critical step in managing pt expectations for veneers?
Mock up
What is used to verify midline, incisal edge position, and occlusal/incisal plane?
Mock up
What allows the ability to communicate changes to the pt and verify parameters including occlusal scheme (canine guidance, edge to edge occlusion, etc)?
Mock up
Helps create correct esthetic placement of tooth surface on dental arch -> simple way of visualizing positions in new smile design
Mock up
Helps avoid excessive healthy tooth reduction
Mock up
How much thickness is needed to change the hue of a tooth by one shade?
0.2 mm
What veneer thickness is most commonly used?
0.3 - 0.5 mm
If minimal shade changes/tooth position are needed, the prep may not include the full width of the _________ _________
incisal edge
If a tooth needs to be “moved” lingually or a large increase in shade is needed, the prep may require replacing the full width of the incisal edge, ending in a _______ ________ w/ the enamel on the lingual surface of the tooth
butt joint
When is there no need to prep the tooth subgingivally?
In minor or non-shade changes
What is meant by minor shade change?
1 or 2 shades lighter
When may subgingival margin placement be necessary to achieve desirable esthetic results?
Gingival exposure when smiling
When are subgingival margins unavoidable?
Decay or old fillings extending under the gingiva
Teeth that need additive porcelain/glass due to an un-esthetic position of the tooth and/or tooth wear that has thinned the enamel can be easily __________ if the final thickness of the restorative material is not used as a guide
over-prepped
What have different cutting depths within themselves, relative to the enamel thicknesses of the facial surface of the incisors?
Diamond depth cutters
What is designed to cut to a depth limited to the radius of the wheel?
Self-limiting depth cutter
The wheels on self-limiting depth cutters are limited to penetrating the enamel until what?
The shaft is flush with the tooth surface
Restrictions to enamel are a necessity for marginal tooth preps and bonded restorations, including ceramic veneers, as exposure of the dentin margins may __________ bond strengths and increase the change of ___________
reduce; micro-leakage
When is micro-leakage minimal or none at the tooth/luting composite surface and negligible in the porcelain/luting composite interface?
When prep margins are completely in enamel
Avoid final margins in areas that risk _________ exposure
dentin
Patches of dentin exposure are not a problem during the prep, as long as finish lines are kept on __________
enamel
In situations such as extensive carious lesions in gingival areas, placement of the subgingival margin can go as deep as to be placed on the dentin or cementum. What will become an issue?
Obtaining successful bond
(use common sense to determine need for full coverage)
Which margin preserves more natural tooth: shoulder or chamfer?
Chamfer
Which margin has more resilience to strain on porcelain stresses: shoulder or chamfer?
Chamfer
Which margin is preferred for all margins, regardless of its placement (supra- or subgingivally)?
Chamfer
The prep should stop just short of breaking the _________
contact
The proximal margin on teeth are are free from color alteration or with “discreet discoloration” should be hidden by the prep made far enough into the contact area so that the proximal wall will end _________ mm facial to the actual contact area
0.25
What are the advantages of preserving the contact area?
- Won’t have to reproduce contact area
- Prevents displacement of teeth that are not periodontally stable
- Try-in is easier (no need to adjust contact area)
- Bonding/finishing is easier
- Brushing/flossing is easier
When may specific prep of the interproximal area be required to allow the tech greater freedom in alteration of form or position?
Closing diastema
Changing shape/position
Caries
Defects
Existing fillings
What is the most conservative veneer prep?
Window
Providing a wide vertical stop to resist loads by covering the _________ ________ lessens the stress concentration in them
With 1.5 - 2 mm prep, this enhances the mechanical resistance and esthetics. The gradation effect of __________ can only be obtained if the incisal edge is prepared like this.
incisal edge; translucency
T/F: The esthetic outcome through coverage of the incisal edge is the most desirable method for pts
True
Which prep technique?
Easier to prep
Can be indicated on teeth w/ limited B-L width
Difficult to reposition veneers during cementation
Incisal butt joint
Which prep technique?
Only used when there’s thick enamel at incisal 1/3
More technique sensitive
More positive and predictable seat during cementation
Incisal overlap w/ lingual chamfer margin
Which prep technique?
If a very thin notch is left at incisal edge, it may break at lab
Extra porcelain is fired into this area, which will prohibit the natural seating of the final veneer
Incisal overlap w/ lingual chamfer margin
Which prep technique?
If the palatal chamfer is prepared thinner than it should, the result is an overbulked lingual extension. This will cause discomfort to the pts tongue, and if its thinned down, the porcelain in this area will be prone to micro-cracks and fracture
Incisal overlap w/ lingual chamfer margin
T/F: Interim restoration is an integral part of the tx process w/ the ability to communicate w/ the pt and lab what enhances the pt’s smile
True
Interim restorations are constructed from the diagnostic __________, with many pts not able to determine their desires or visualize the final result by just discussing changes verbally. Utilizing provisionals gives the pt a preview of the final planned result
wax-up
When cementing veneers, what should be used to isolate?
Rubber dam
What has become the gold standard for isolating bonded restorations, like veneers?
Rubber dam
Which clamp is used for isolating anterior teeth with a rubber dam?
212 satin steel clamp
What can be used to protect adjacent teeth and makes it easier to clean excess cement when cementing veneers?
Teflon tape
If the veneer has not been etched in the dental lab, etch with ___________ _______, which has 10% HF acid
porcelain etch
The time of etch depends on the ceramic materials used. What are the etching times for the following materials?
Porcelain
Empress
Emax
Porcelain: > 3 mins
Empress: < 1 min
Emax: 20 seconds
When is the best result of etch achieved because it minimizes contamination of the etched surface and increases bonds?
After try-in
If the surface has already been HF acid etched at the lab before try-in, what should the interior surface of the veneer be covered in to remove organic materials and clean the surface of debris? For how long?
37% phosphoric acid for 15 seconds
Using _________ on etched ceramics makes the retention of the bonded ceramic joints possible with its high wettability and its chemical contribution to adhesion
silane
Coupling agent
Silane
Once the veneer is dry after applying silane, apply _______ with a brush or small cotton pellet. Should you light cure at this stage?
bond; NO do NOT light cure!
Apply __________ to enamel for 15-60 seconds, keeping it off the dentin. For the last 15 seconds, spread it over the ________ with a disposable brush. Then, thoroughly wash and dry the teeth.
etch; dentin
After etching the teeth, dentin should only be blot dried with a cotton pellet to achieve ______ __________
wet bonding
After wet bonding the dentin, _________ is applied over exposed dentin area, left in place for _________ seconds, and then very gently dried until the carrier of the primer evaporates
primer; 15-30
Once the glossy appearance of the primer is achieved, ________ is applied to enamel and dentin. Should you light cure at this stage?
bond; NO do NOT light cure!
What types of cement are preferred for porcelain veneers?
Light curing
Dual-curing luting composite
What is the advantage of using light curing or dual-curing luting composite cements on porcelain veneers?
Longer working time
(can remove excess prior to curing, which shortens the finishing time)
Which cement?
Color stability is better
Light curing
Dual-curing luting composite
Which cement?
Indicated for thicker or darker veneers
Dual-curing luting composite
Expose the excess cement to the curing light for 1-2 seconds from each __________ surface, obtaining a gel-like consistency. Remove and finalize the cure. If you do this, you ensure that the veneer has not moved before finalizing the cure.
quarter
