Daily Lab Projects 50% Quiz, Midterm, Final 50%
You must pass both the lab and the written independently
Of students will have over $100,000 of debt
2000 2004 2008 2012
85K
105K
160K
240k
Of female dental students Cost of tuition
30%70% 0%
PFM Gold All-Ceramic
7 years ago30%70% 0%
PFM Gold All-Ceramic
7 years ago30%70% 0%
PFM Gold All-Ceramic
7 years ago30%70% 0%
PFM Gold All-Ceramic
7 years ago30%70% 0%
PFM Gold All-Ceramic
7 years ago30%70% 0%
PFM Gold All-Ceramic
7 years agoDental School Private Practice
0.5mm chamfer878K 016
Gold Preparation
3-6° taper
1mm supra-gingival
1mm axial
1-1.5 occlusal reduction
Functional cusp bevel
B L
PFM crowns as seen here can have metal exposed in unestetic areas to allow for more conservative reduction in those areas
(1mm vs 1.5mm)
1mm heavy chamfer878K 018
3-6° taper1mm supra-gingival unless in esthetic zone may
place 0.5mm sub-gingival using cord for controlled margin lowering
1.5mm axial
1.5-2mm occlusal reduction
or
847kr 018
PFM Preparation
1mm round shoulder
follow reduction for gold if you have areas that you want to keep
in metal
Functional cusp bevel
B L
Things to avoid with Finish Line design
“lipped”
When you use greater than 1/2 the diameter of a chamfer diamond or greater than the entire
diameter of a shoulder diamond. Therefore it is easier to lip a finish line with a chamfer diamond
than a shoulder diamond.
BeveledShoulder
We do not use a beveled shoulder at MUSC
chamfer lip shoulder lip Do not over reduce
over reduced
PFM alloys: usually
phosphate bound
investment
High noble: ≥ 60% with ≥ 40% goldNoble: ≥ 25% nobleBase: < 25% noble
Porcelain bonds through covalent chemical bond to oxide layer. Must add tin indium iron or gallium for
oxide to form.
Must have CTE of metal>ceramicwant melt temp 300-500 > porcelain fusing temp
Ante’s Law
In 1926 Ante suggested that is was unwise to provide a fixed partial denture when the root surface area of the abutment was less than the
root surface area of the teeth being replaced.
never more than 3 pontics, even 2 is
risky
CEMENT
Zinc Phosphate: Classic cement, long track, Low PH (sensitivity without varnish?) No Bond,
Mixed on frozen glass slab to increase working time. Not pop anymore
Glass Ionomer Chemical bond to tooth, FL release, Good strength, sensitive to moisture/
desiccation during placement, CTE same as tooth
Zinc Polycarboxylate weak but present bond to tooth esp enamel through calcium chelation, kind
to pulp
RMGILike GI but lower solubility, higher strength. Bad CTE, contradicted for all
ceramics.
ResinGood mechanical properties and high bond, ideal for all-ceramic restorations
Terminology
Fixed Partial Denture
Retainer: 1:2 ratio ideal, 1:1 very minimum and must be small span(1
pontic)
Soldering Flux: dissolves oxides and Increase flow and Wets melts 150 below fusion temps.
Sodium PyroborateBoraxSilica
0.25mm
Strength depends on SA but Height most important
anti- Flux: graphite, limits area of flux
double width, strength doubleddouble height strength cubed!
Bridges may have rigid connectors …
… or non-rigid connectors
(Ideal)
(Contraindicated for mobile retainers)
All Ceramic
6-10° taper In Posterior preserve enamel at margins!
1.5mm axial
1.5-2mm occlusal reduction
1mm round shoulder
more rounded
Functional cusp bevel
Round internal line angle
847kr 018
1.0mm
“Measure Twice Cut Once”
preserve enamel
B L
“No form of Nature is inferior to Art; for the arts merely imitate natural forms” Marcus Aurelius
ConsExpensive
1. Usually not esthetic 2. Prep must have retention 3.Porcelain breaks off over time 4. Must hide unaesthetic
margins below tissue
Shoulder
(variations)
Sloped Shoulder Beveled
ShoulderShoulder
(rounded internal line angle)
Heavy Chamfer Chamfer Feather
Terminology Variations
60%sub-gingival margins will be exposed within
2 yearsShillingburg, Jr, DDS, Herbert T.. Fundamentals of Fixed Prosthodontics, 3rd Edition. Quintessence Publishing (IL), 011997. 25.3.4)
Shoulder
(variations)
Sloped Shoulder
Beveled Shoulder
Shoulder (rounded internal line angle)
Heavy Chamfer
Chamfer Feather
Terminology Variations
Avoid a lipped margin
greater than 1/2 the
diameter of a chamfer diamond
greater than 80% the
diameter of a round shoulder
diamond
1. Describe a PFM crown preparation on an anterior tooth including mm of reduction, planes of reduction, reduction for metal lingual vs ceramic lingual and finish line design.
2. Describe a PFM crown including layers, thickness of layers, composition of
ceramic, bonding mechanism
0.5mm chamfer878K 016
Gold Preparation
3-6° taper
1mm supra-gingival
1mm axial
1-1.5 occlusal anatomical reduction
Functional cusp bevel
B L
1mm heavy chamfer878K 018
3-6° taper1mm supra-gingival unless in esthetic zone may place 0.5mm sub-gingival using cord for controlled margin
lowering
1.5mm axial
1.5-2mm anatomical occlusal reduction
or
847kr 018
PFM Preparation
1mm round shoulder
follow reduction for gold if you have areas that you want to keep in
metal
Functional cusp bevel
B L
All Ceramic
6-10° taper1mm supra-gingival unless in esthetic zone may place 0.5mm sub-gingival finish line using cord for controlled
finish line lowering. In Posterior preserve enamel at margins!
1.5mm axial
1.5-2mm occlusal reduction
0.8-1mm round shoulder
non-anatomical=smooth and rounded
Functional cusp bevel
Round internal line angle
847kr 018
1.0mm
“Measure Twice Cut Once”
preserve enamel
B L
847kr 018
2mm2mm
At MUSC we must achieve a circumferential 2mm
vertical ferrule effect where the
finish line is on solid tooth structure cervical to a
filling or core.
3mm 3mm
It is important to maintain biologic width where 3mm is
needed between the margin of the crown and the crest of
the ridge. If this is in violation, or predicted to be in violation,
a perio consult for crown lengthening is mandatory.
Critical errors that may result in an automatic failure
“lipped”
When you use greater than 1/2 the diameter of a chamfer diamond or greater than the entire diameter of a shoulder diamond. Therefore it is easier to lip a finish line with a chamfer diamond than a shoulder diamond.
BeveledShoulder
We do not use a beveled shoulder at MUSC
chamfer lip shoulder lip Do not over reduce
over reduced
1.0mm
847kr 018