7. ACC II Flashcards
Indications for cubic zirconia
- Anterior and PM crowns
- Anterior and PM bridges with one pontic
Minimal thickness for cubic zirconia
1.2 mm
Differences between regular zirconia and more translucent zirconia
More translucent zirconia
- Requires more reduction
- Gentler handling during chairside adjustments (esp posterior restorations)
- Use with caution in molar region
Esthetics for translucent zirconia (are/aren’t) consistent
aren’t- longevity of the stain??
Describe inlays and onlays
Inlay
-Intracoronal restpration made outside the tooth
Onlay
-Restoration with one or more cusps and adjoining occlusal surfaces or the entire occlusal surface and is retained with mechanical or adhesive means
Indications for inlays/onlays
- High esthetic demand
- Good OH and low caries rate
- Durable alternative to posterior resin and amalgam restorations
- Esthetic alternative to gold inlays and onlays
- When optimal contours can’t be achieved with direct restorations
Advantages of inlays/onlays
- More wear resistant (direct rest.)
- Conservative prep (FCC)
- Less marginal leakage (resin)
- Enhanced contours (resin)
Why might inlays/onlays have less polymerization shrinkage compared to resin
Leakage is related to polymerization shrinkage and high CTE
-Thin layer of resin is used to lute inlay/onlay –> less shrinkage
Rank the following in order of most to least tooth reduction (with thier percentages)
- Onlay
- MO inlay
- ACC
- MOD Inlay
- PFM crown
PFM (76%)>ACC(72%)>Onlay(39%)>MOD inlay(27%)>MO inlay(20%)
Contraindications for inlays and onlays
- Patients with high caries risk
- Patients with parafunctional habits
Onlay retention comes from
Bonding rement cement/adhesion
T/F E.max and Empress are indicated in bruxers
f- Zr is
Can you use Zr for inlay/onlay? Why/ why not
No because the bond is not as durable with resin cement because Zr has no glass phase
Disadvantages of inlays/onlays
- Accurate occlusion can be hard
- Areas of occlusal adjustment need careful finishing and polishing (time consuming- rough porcelain is abrasive against the opposing arch
- Wear of composite resin luting agent –> marginal gaps
- Finishing of margins can be hard in interproximal regions due to access –> perio disease
Occlusal adjustments for inlays and onlays are made (before/after) cementation
after
Marginal gaps
100 nm
What determines the general outline of the prep for an inlay/onlay
caries
Interproximal margin of inlay/onlay is done with what bur
shoulder
Min. dimension for occlusal reduction for onlay prep should be
1.5 mm
Min dimension for the width of the gingival floor for onlay and inlay
1-1.5 mm
Min width of inlay isthmus prep
1 mm
Min isthmus depth for inlay
1 mm
Onlay prep with axial reduction is commonly done for what reason
overcome poor blending of restoration to facial surface
Ideal prep for onlay is _ occlusal reduction with the cavosurface margin between what thirds of the tooth
1.5-2mm…. incisal and middle thirds
Margins should be _degrees at the butt joint of an inlay and why
90… bevels are contraindicated
Margins for pnlay are done with what bur and why
deep chamfer because you want a obtuse angle (>90 degrees at the but joint) to remove unsupported enamel prisms
Before prepping the tooth for inlay/onlay what should you do and why
-Mark the occlusal contacts with articulating paper
Done to ensure no margins are on occlusal contacts and help restore normal occlusion
Margins on inlays and onlays should be (supra/sub-) gingival
supra
Need POI- therefore need to eliminate undercuts- what materials can block them out
RMGI or resin
Proximal clearance should be at least _ mm to allow for what
0.6 mm to allow clearance of impression material
What is used to make the temporary restoration for an inlay/onlay
-Telio CB Inlay (formerly called fermit)
Is telio CB inlay light cured
yes
Telio CB inlay is also used to
cover implant screw abutments
What should be given to the patient after placing a temp with telio CB inlay
superfloss (locks in interproximals for retention)
The axial walls in an MOD cavity prepared for a cast gold onlay should angles (diverge/converge) from the (gingival/proximal) walls to the (pulpal/axial) walls
converge…. gingival… pulpal
For all inlays and onlays the internal walls taper from (external to internal or internal to external) and all external walls (converge/diverge)
internal to external… converge (this prevents undercutes)
Advantages of porcelain laminate veneers
- Conservative
- No anesthesia needed
Indications for porcelain laminate veneers
- Discolored, pitted, fractured anteriors
- **multiple discolored but otherwise sound teeth
Concern with porcelain laminate veneers
- Inadequate reduction –> over-bulked (perio health)
- Must be bonded to enamel
- Optimal isolation needed
- Knowledge and experience in shade alteration
What are the three (4) veneer preps and which are the most and least conservative
-(nor prep veneer) more conservative> Traditional > Extended > Full
Describe the differences in veneer prep designs
Traditional
- Proximal contact is preserved
- Most conservative
Extended
-Additional overlap (more insical reduction
Full
- Proximal contacts are removed
- Long overlap (most incisal reduction)
The preferred design for porcelain laminate veneers (does/doesn’t) maintain part of the insical edge in enamel ….what happens if this is not possible
does … if not possible a modified prep with a lingual extension is needed
Give the ideal reductions for a conventional prep for the gingival, middle and insical thirds of the tooth
Gingival= 0.3 mm Middle= 0.5 mm Insical= 0.7 mm
Overbulking of veneers can lead affect (fricative/sibilant) sounds
fricative
Minimum thickness of a lithium disilicate press veneer is at the gingival margin aspect (thinnest part of veneer)
0.3mm
Describe the thickness of enamel for anterior teeth in the gingival, middle, and insical thirds
Gingival= 0.3mm Middle= 0.5 mm Insical= 1mm
There are two types of depth cutting burs than can be used for veneers- which is recommended
0.3 mm (verses the 0.5 mm)
If you want to increase the insical edge with the veneer what must you include in your prep
Insical reduction and lingual finishline
What must you do in order to achieve equal reduction
stick to existing plane of tooth
How many planes are on the facial surface of incisors
3
Veneer margins must be on
enamel
what if the tooth you want to veneer has a class III filling
Extend the prep to include the restoration
**veneers are contraindicated in teeth with extensive restorations
What materials can you use for veneer provisionals
- Integrity
- Flowable
How do you cement the provisionals with veneers
spot etch technique (no retention form in prep)
Zirconia (is/isn’t) a glass ceramic
isn’t
What materials are used to make veneers
- Feldspathic porcelain (not commonly used anymore)
- Empress (leucite)
- E.max
What are glass ceramics
made of a glassy (silica) and a crystalline phase
What veneers and crowns are the most esthetic
empress
Which is preferred and why empress or E.max
e.max due to increased strength and more conservative prep
Which has higher flexural strength (CAD/Pressed) E.max
pressed
Cubic zirconia is (weaker/stronger) than E.max
stronger
With is indicated for 3 unit bridge not extending past the PM region (pressed/CAD) LD
both
Connector size for 3 unit Emax bridge
16mm2
Connector size for tetragonal zirconia bridge
9-12 mm2
Connector size for cubic zirconia bridge
16mm2
T/F Cubic zirconia bridge can be any size and any location
F- true for tetragonal but cubic is limited to 3 unit not extending into molar region
What restorative materials require adhesive bonding and which can be bonded either adhesively or conventionally
Need adhesive
- Feldspathic
- Leucite
Either
- Emax (CAD and Pressed)
- Tetragonal and cubic zirconia
What restorative materials require selection of natural die (or stump) shade
Yes
- Leucite
- E.max (both kinds)
No
-Tetragonal Zirconia
Not sure
-Cubic zirconia
Which restorative materials require try in paste
Yes
- Leucite
- E.max (both kinds)
No
-Tetragonal Zirconia
Not sure
-Cubic zirconia
