Hot Topics Fixed Final Flashcards
a dental prosthesis worn for varying periods of time, which maintains esthetics, provides masticating surfaces and protects the hard and soft tissues
provisional
Ease of fabrication and alteration Strength and resistance to wear abrasion Inert to eugenol Poor thermal conductivity Esthetically acceptable- tooth colored Color stable Non-irritating to pulpal tissues
desirable characteristics of provisionals
Establish occlusion and occlusal plane Verify tooth prep reductions size and position of missing teeth determining path of insertion evaluation of pontic design evaluation of esthetic demands establishment of proper tooth contour and form Aid in determining condition of cracked tooth
diagnostic characteristics of provisionals
Protection Maintenance of healthy tissues Facilitates impression Patient evaluation Evaluate pontic design Maintains teeth in position Provide tissue form for implants Maintain tissue after crown lengthening
Benefits of fabricating accurate and esthetic provisional restorations
Jet acrylic- Lang
Duralay temp- Reliance
Polymethyl methacrylates
Bis-GMA composite
Light cured resins (PEM, urethane dimethacrylate)
Hybrid provisionals
Best abrasion resistance
Best color stability
Good polishability
Good marginal finish
PMM advantages
High heat polymerization (165)
High shrinkage
Monomer irritant to pulp
Eugenol deteriorates resin
PMM disadvantages
Indirect techniques
Long-term provisionals
Conventional provisionals
Long span provisionals
PMM indications
Split line- Lang
Trim- H. J. Bosworth
Snap- Parkell
Polyethylmethacrylate
Low shrinkage
Rubber stage to set
Longer working time
Lower polymerization temp (125)
PEM advantages
Poor hardness Poor abrasion resistance Poor color stability Poor finishability Eugenol deteriorates resin
PEM disadvantages
Short-term provisionals (1-3 wks)
Direct technique
Short span
PEM indications
Lowest shrinkage
Negligible heat of polymerization
Lowest pulpal irritability
Eugenol does not affect resin
Epimine advantages
High cost/unit
Air bubbles
Poorest in color stability, hardness, abrasion resistance
Cannot be corrected by additions
Epimine disadvantages
most biologically compatible when used in direct technique
Epimine advantages
Low shrinkage
Corrected by additions
Can be radiopaque
Hybrid advantage
Brittle
Repairs and mixing are more difficult
Expensive
Hybrid disadvantage
Long span restorations
Long term provisionals
Hybrid indications
Pink wax
ESF
PVS impression
all are matrices for provisionals
Thickness of polypropylene or poly vinyl matrix
0.02”
Diagnostic wax up Duplicate cast: Plaster ESF on cast with plaster index Minimal preparation on plaster cast Shell provisional by cast-ESF-index assembly Abutment teeth preparation Shell provisional reline intraorally trim, finish and polish provisional
Indirect-Direct Reline Technique
Artificial teeth of a partial fixed dental prosthesis that replaces missing natural teeth, restoring function and appearance
pontic
Which mucosal contact should you never use?
Saddle ridge lap- impossible to clean
Which mucosal contact do we use?
Modified ridge lap- pretty to clean but still esthetic, convex on lingual/palatal side
Which mucosal contact is egg-shaped?
Ovate- very esthetic but cannot be used for residual ridge with defects
What are the issues with conical pontics?
may create food entrapment on broad residual ridges
Which type of pontic design to use in the posterior?
-hygienic pontic
Minimum, pressure free contact with ridge
No acute angles with ridge
Occlusal table equal to the adjacent teeth
Rigidity
Open embrasures
Convex, smooth, properly finished tissue surface
Pontic requirements
No tissue blanching
Pass thin floss
No visible space under contact with tissue on visually esthetic areas as possible
pontic contact requirements
What is the thickness of the pontic contact in metal?
2mm x 2mm
proxabrush
floss threaders
super floss
great oral hygiene products to clean pontic
To establish a 1mm wide band of metal closely adapted to the tooth, this minimizes dissolution of the luting agent
internal margin objective
What is the space for the luting agent?
25-35 micrometers
Proximal contact adjustment- should grip shim stock
1st step in delivery sequence
Shim stock
most accurate way to adjust proximal contacts
Sequence of using the round wheels
Blue, pink, gray
What should you not use to adjust metal proximal contacts?
Coarse diamonds- they leave rough surface that is difficult to finish
Marginal integrity- disclosing wax, rouge in turpentine, powdered spray (occlude) other detection pasts
2nd step in delivery sequence
Which bur is best used to adjust intaglio surface?
1/2 round or 330
Stability
3rd step in delivery sequence
These can all affect what part of the pontic?
Nodules, distortion during impression or cast, parallelism between abutments, undercuts
All can affect stabilty
Occlusal adjustment
4th step in delivery sequence
Which occlusal contacts are you assessing when adjusting the restoration for delivery?
-centric and eccentric occlusal contacts
Which burs can you use to adjust occlusal contacts
white stones
fine diamonds
fluted carbides
Lateral and protrusive contacts
eccentric occlusal contacts
metal crown occlusal surfaces are best finished with what kind of burs?
- carbide
- white stone
- green stone
which bur is best to enhance and maintain the anatomy of the crown?
-small football bur
What is the color progression of the gold polishing kit?
Abrasive silicone wheels:
- coarse brown
- dark green medium
- light green fine
Contouring
5th step in delivery sequence
Adjust these during what step of delivery?
Gingival third
Embrasures
Pontic design
contouring (5th step)
Flexible diamond disk
porcelain grinding wheel
Diamonds
Porcelain adjustment kit, abrasive wheels and points
-Armamentarium for contouring porcelain
A fusible metal alloy used to unite the edges or surfaces of two pieces of metal
solder
This is a designation given to gold solders to indicate the proportion of pure gold contained in 1000 parts
Fineness
High fusing alloys that slightly melt beneath the softening point of the parent alloy to be joined; should flow well above the fusion range of the subsequent applied porcelain
pre-ceramic solders
What is the gap distance for soldering complete gold FPDs?
-0.25mm
Difficult (narrow melting range) Volatization of base metal Microporosity or pitting Not good bond with porcelain Color Corrosion
Disadvantages of Pre-Ceramic soldering
Low fusing alloys that melt bellow the pyroplastic range of the porcelain
post-ceramic solders
Less chance of sag or deformation of the framework
Slightly weaker and more brittle solder joint since frame work cannot be quenched
Small gap space for solder= incomplete joint
Large gap space for solder = decreases strength, higher porosity, higher meniscus, more difficult to solder
disadvantages of post-ceramic soldering
This is used to limit the spreading of the solder
It is placed in areas of the casting before the flux to prevent the flow of the molten solder
Typically graphite or rouge (iron oxide) with turpentine as a solvent are used in this
Antiflux
This is a substance applied to the metal surface to be soldered to remove oxides or prevent their formation Borax Glass (Na2B4O7) with gold alloys comprise this substance
Soldering flux
Soldering investments contain what ?
Fused quartz
How do you restore fatigued color vision?
-view pale blue or gray surface between shade matching
This is the phenomenon of two objects appearing to match in color under one condition but showing apparent differences under another
Metamerism
What are the 3 components of color
Value- light/dark
Hue- color
Chroma- saturation
Vita shade guide color progression from left to right
A- red-brown
B- red-yellow
C- gray
D- red-gray
First step in vita shade selection
Hue
2nd step in vita shade selection
Chroma
3rd step in vita shade selection
Value
What should you do to enhance your ability to distinguish value?
squint- decreases light –> diminish cone sensitivity, increase rod sensitivity
Steps in Vitapan - 3D shade guide
Value, Chroma, Hue
Which shade guide is better at reproducing value?
Vitapan 3D master shade guide
How do you trick the eye in to thinking teeth are wider/narrower?
Move line angles out/in
What are the disadvantages of the external color modification and characterization?
- causes a loss of fluorescence
- increases the effect of metamerism
How do you externally modify chroma?
-add yellow or orange
How do you externally modify hue?
- add pink/purple to move towards red
- add yellow to move away from red
Adding stains lowers the ____ of the restoration and increases the metameric effect
-Value
Degree of luster is dependent on what factors
Temp and time
This process strengthens a porcelain restoration similar to polishing
Glazing
