Pros Class Notes for December 14 2001 Didactic Exam

Nov. 5 | Nov. 9 (1) | Nov.9 (2 | Nov. 12 (Lindquist) | Nov. 12 (Schneider) | Nov. 16 (1) | Nov. 16 (2) | Nov 26 | Nov. 30 | Dec. 3 | Dec. 7

Pros, 11/5/01 7:58 am

Dental Ceramics

ceramics have been around around a long time. ceramics and porcelain in
dentistry around since 19th century....

ceramo metal restorations began to really be usable in the 1950s.

pocelain is in a powder. we"stack" it on, then bake it.

we'll mix the porcelain initially ith glass slab and stack in that
manner.

Porcelain for metal bonding (some extra things that might not be in
handout)

crystalline solids
glasses
silica
porcelain -- crystalline islands wihin a matrix of glass (usually fudes
silica)

comment on physical properties -- por. has 30-48 psi compressive
strength, that's good. but it has a low tensile strength. and a low
sheer strength -- this is because of its lack of ductility (not
flexible)

classifications of dental porcelain:
- high temp maturing 1288-1371 degrees

- medium temp maturing: 1093-1260 deg. por. denture teeth, some jacket
porcelains.
- low temp maturing: 871-1066 deg. most ceramo metal restorations

requirements for a ceramometal porcelain

1. physical, chemical, and optical properties cannot change
substantiallly with repeated firings -- BUT.... SiO2 glass is really the
basic structure of a ceramometal porcelain.

2. he por must fuse at a temp that is somewhat lower than the melting
temp of the alloy.
BUT - Fusion temp for most med and high temp porcelains are greater tan
that of mopst ceramometal alloys.

3. coefficients of thermal expansion (alpha) of the porcelain must be
closely matched.
BUT - coefficients of thermal lexpansion for medium and high temp pors
are much lower than tose of ceramometal allloys. The addn of oxides
increase CTE by the "loosening" of the atomic structure -- you want a
10% mismatch -- por. has a 10% lower CTE than the metal.

However -- the disruption of the glass by the addition of oxides maeks
crystallization more likely. called deitrification. the more crystals
you have, the more opacity you have, so the more less esthetic it is.

So - it is crucial to follow manufacture requirements.

chatr: how temp temp on the physical properties of porcelain

takes more energy to break more crystalne structure -- igher modulus of
rupture with more crystals. but there is a compormise between strength
and esthetics.

4. the por must be capab;e of bonding t the alloy....

Porcelain-alloy bond:
1. mecahnical
2. compressive - not part of the physical bod mechanism oer se, but
rather palcement of the por ..... missed it....
3, molecular components -
     a. van der wals
b. chemical - oxide bonding between elemets in the alloy and the SiO2
network.
Need: diffusin of trace elements

take care whn you form initial bond to oxide layer, creating the opaque
por.

por. manufacturing...
materials"
- quartz (SiO2), feldspar clays, additional modifying oxides
Fritting
- repeatedly melting and rapidl cooling the raw materials to achieve a
homogeneous powdered glass "frit."

por. types (low fusng)
opaquw, body (denting) and incisal (enamel), modifiers and stains.

if staining doesn't wor k to well, ou can just sandblast it and try
again.

opaque:
- the basic glass to which tetravalent, realitively insoluble woops --
couldn;t get it all.

body and incisal:
- basic glass to whihc small amounts are addded for opacity -- very
little in incisal

modifiera and stain
larger amounts of colorant. can be sed internally or on the surface...
In addition,the viscosity, thermal expansion, and f temp differs
slightly between the different types of porcelain. don't want opauque to
move....
single central incisor is one of the toughest restoration ou can do....

case -- diag cast , wax cutback, invested and cast, with sf52 metal.....
then it is fitted to die.... you use disappearing margin....

lab considerations:
- degassing (oxidation)
- opaque application
- condensation of percelain

degassing...
opaque pplication - brush a noce thin layer on, this gives o2 access to
the metal, enhances strenght. gotta add coats till you see no grey
underneath.

body and incisal por. addition -- pnk is body...

mix por with water initially. it is aplied to the crown ina slurry --
but it still needs to hold its shape. liquid is mostly water, but also
might conmtain binders to ais in molding the por.
mechanisms:
capillary,surface tension, mechanical agitation.

the better the condensation, the better the strength qualities.

uncondensed opor has more shrinlaage (crystall shrink after every
firing)

effect of condensation is unclear>

firing:
drying, sintering (bring to firing temp), vacuum firing, releasing
vacuum at end of cycle, glazing (gives shiny surface)

Dryiing:
- not all water is removed by condensation. Slow introduction of the
condensed por. into the oven is necessary to avoid steam production and
explosion of the por. mass. Don't wat por. t bust. gotta get all the
water out.

vacuum friring
- decreases porposity of por. by drawing out air incorporated during
stacking and condensation. (porposity leads to  decreased, increase
opacity.)

vacuum firing geives etter esthr=etics

sintering: fusinf particles.....


common to use graphite pencil to mark line angles -- this is while crown
is on cast...

glazing..
manytimes we get crown back in bis baked stage - it look s roughened or
chalky. in this state you can check occlusion.

autoglaze vs. overglase. auuto is almost the always used.

alminous percelain is high crystalline .. see h.o. ground = bis baked.
glazed  = glazed...

porcelain can be pretty abrasive to opposing dentition....

project:

perp it.
do registration
custom tray for pvs impression - put adhesiveon tray. use nonlatex fre
impression fill tray with brown, blue around tooth.... (light vs hea vy
ody). impressio needs to be deepo and wide enough. need good
buccolingual room. bevel. clip interprox
- box it
- pur it with tpe 4 - silky rock. pour slowly . wait 45 min before yu
seperate. ese it out. bffal kniofe. trim on model trimmer. careful not
to trim facial surface of anterior teeth. 1012mm from te margin tot eh
tissue (impression should be that high) has to be thin enough to mounton
cast. 10-12 from the tissue. 20mm wide is enough for pins and
strength... on internal lingual surface.... slight bevel so you can
remove.
- pindex. do good with countersink. make sure pins fit before gluing.
short pins on lingual. grey on smal, white on long.
- box it. pour. don't forget supersep. sep after 45 min.
- section. 5 removable sections
- trim die. emergence profile. abrd parker works well. some like
weidelstat.
- mount to mandib model. (already mounted....
Barry Hillam
barry@hillam.net

Pros, 11/9/01 8:05 am

Esthetic Considerations

we'll bring in knowledge of dental anatomy for this....

list all problems
- sequence tx
- diagnostic wax up

communication:
-patient education
- dentist's education

Choices of Esthetic restorations
- 3/4 crown
- copmosit
- veneers
- resin bonded bridges
- pfm
- pjc
- implnats

Team approach
- restorative dentist
- periodontist
- orthodontist
- oral surgeon
- endodontist

the general dentist is the one in charge. The ortho needs to do what
fits into our tx plan. same with surgeons and periodontists.

case -- inapropriate enso access: remaining pulp: discoloration. You can
go in and do some internal bleaching. teeth were also tweaked, ortho was
best option, although could try restorative. tx: accessed chambers
better, got necrotic stuff out, bleached. straightened....

Perpectives of dental esthetics
1. ginigival hx and architecture
2. harmony within the dental arch
3, individual tooth contour
4. surface textre
5. color
6. prep and fabrication variables

Gingival hx and ar.
- perio hx
- marginal tissue recession
- loss of interdental papilla (black triangle - tough to fix)
-?

gingival hx - look at whole perspective. check for general vs. local
problems. address this early in d. control of tx plan.

"disruption of the gradation of perspective compromises the continuity
of the patient's smile." (PPAD 19999;11(6):721-28

cae - gold based veneer wiith acrylic facing...

pictures -- differring smile lines -- varying amount of goingival
display can be due o different factors.. can be skeletal ....

Harmon within the dental arch
- Incisal edge relationships
 prox contact..
- ?

Incisal edge relationships
- varied: natural (youthful)
- Uniform: aged or artificial. makes patient look older.
Prox contactlocation
- teeth approx a trapezoidal shape.
" the location of the anterior contact points that should be
referenced."
prox contact goes more gingival as ou go posterior.

OPen contacts: some

Embrasure forms
- should be even on both sides...
as you go post, the ging embrasure gets smaller, occlusal gets bigger.

embrasures on FPD's need to be sufficiently opeed up. We tend to
com[promise a little more on lingual embrasure for srength, but on the
facial we need to make it look good.

Long axis Angulation
- incisal edge
- ging contour
-crest of concavity
- embrasures

"The axiakl inclinations are referenced from the midline." (PPAD)

Mesio distal width considerations
- ortho correction
- modified tooth contours and embrasures
- surface texture alteration
- overlapping or spacing
- value change

Relative tooth widths
- "Golden proposrion -- width of central has a relation to width of the
lateral and cuspid. Same proportions exist elsewhere in nature.

Adjstnig line angles canmake teeth appear wider.

playing with line angles and embrasures can compensate for discrepancies
in space size.

Inciso gingival length problesm:
- incorporatin a cervical line angle
- surface texture alteration
- surgical correction
- use of gingiva; colored porcelainporcelain or stain

regarding long narrow teeth, a little more mesiodistal surface texture
ehlps (?).

Short teeth -- can do crown lengthening, highlighting surface texture

individual tooth contour
- what does easch tooth look like (from your dental anatom)? apply this
to restorations. consider indviual charactersics -- distal embrsre,
incisal embrasre, creating symmmetry with thee components

probably th emost challenging restoration is central incisor. symettry
has to be perfect. elps to get crown in bis baked stage. defect
incisally was added to match the other, slight staining, gl;azing.
overal very nice result.

Tere is an ada code for staining and gl;azing procedures in our office.

case: 8&9 look to round.

Surface Texture
- Macroscopic
   -Developmental depressions and grooves
- microscopic
    - galze

some teeth are very very smooth, snd some have a lot of surface texture.

Surface reflectance
textured surface has ??? missed the rest....

case: single crown on 9. Color is decent, but the surface is way to
smooth. it needed more striations. stands out too much. in another mouth
that smoothness might be fine.

Surface Texture
vertical highlights - illusion of a
horizontal highlights -- illusion of a

G;aze: there is soft, medium, hard

Hard glaze has a very high luster (looked gross to me)

Color -- Hue, chroma, value...

value:
- increased value gives illusio of larger crown -- Dang it!! can't keep
up -- slide went too fast.

case: white crowns, but no opacity... gross! But patient wanted this.
didn't understand the ned for color andn opacity gradations. Certain
teeth have more chroma o gingival 3rd. gotta educate a patient on
appearance of natural teeth.

Esthetics and fx
- harmon between face, lips, teeth
- conducinve to porper phometic fx
- compatible with occlsal requirements

prep and fabrication variables
- prep design
   -? (too fast)

Actually went withth ecrossbite and restred it that way....

tetracx staining -- crown unfortnatelyaveto beopaqued more to mask
staining

To summarize, you must: Evaluate, Diagnose, and resolve esthetic
problem.

---------
Onto project - mount, die hardener and spacer, die lube, wax up. get
embrasures, line angles, etc. same as adjacent tooth. in other words,
full contour wax up.
Barry Hillam
barry@hillam.net

Fixed Pros Student Notes

Nov 9, 2001

Klint Butler

Esthetics

Communication:

a. Patient Education - They need to know what tx options are available

b. Dentist Education - Need to know what the pt expectations are

Team approach:

a. Restorative dentist is in charge

b. Ortho, perio, pros, omfs, endo

Perspectives of Dental Esthetics:

a. Gingival health + architecture

b. Harmony within the dental arch

c. Individual tooth contour

d. Surface texture

e. Color

f. Preparation + fabrication variable/methods

Essentially we are looking at how the perceptive shape of an individual tooth can be altered, and how the elements of esthetic composition affect one another.

Gingival health + architecture:

a. Periodontal health, patient’s home care, need to start with that

b. Marginal tissue recession (prognosis affected by grade of rec. (1-4))

c. Loss of interdental papilla, this is probably the toughest thing to deal with, the ‘Black Triangle Effect’. Very difficult to regenerate lost papilla.

d. Localized alveolar ridge deficiency

e. Excessive gingival display

f. Gingival health, bone loss, localized gingivitis, etc.

Patient’s smile line should portray a nice, even relationship of the gingival height of contour.

Harmony within the dental arch:

a. Incisal edge relationship

b. Proximal contacts

c. Embrasure forms

d. Long axis

e. M-D width considerations

f. Relative tooth widths

Incisal edge relationship:

a. Varied look is more youthful/natural. Centrals a little bit longer, laterals a little shorter than centrals; the cuspids are typically approximately the same length as the centrals. (Maxilla of course)

b. Teeth all the same length, patient looks older, teeth look more worn

Proximal contact location:

a. Teeth are trapezoidal, creates the proximal contacts

b. As you go posterior proximal contact goes more gingival

Embrasure forms:

a. Should be symmetrical on both sides

b. As you go posterior the gingival embrasure gets smaller, the incisal embrasure gets larger (both maxilla + mandible)

c. FPD embrasures are opened up, close to normal; we compromise on the lingual embrasure to have adequate strength for the connector, open on facial so that it looks good.

Long axis location:

a. Looking at the incisal edge, this affects the gingival contour, the crest of convexity, and the embrasures. How they relate to one another will affect all of these things.

b. Incisal ‘picket fence’ look isn’t natural, slight variations

Axial inclinations:

a. Referenced from the midline, anterior teeth have a slight mesial inclination in natural teeth, should carry over to restorative work.

M-D width considerations:

a. Ortho correction, sometimes not utilized as much as should

b. Modifying tooth contours and embrasures can be done chair side as we are looking at fitting restorations, doing this as you are doing composite restorations too

c. Surface texture alteration to fit in with the surrounding dental tissue

d. ‘Golden Proportion’, as you are looking straight on in an anterior situation the width of the central has a mathematical relationship to the width of the lateral to the smaller width of the cuspid

e. When adjusting widths of teeth that are too small, or too large we can adjust the line angles to alter perception of space

Incisogingival problems:

a. More challenging to deal with.

b. Incorporate cervical line

c. Surface texture alteration

d. Surgical correction

e. Use of gingival colored porcelain or stain

Individual tooth contour:

a. The most difficult restoration as far as esthetics is the single central incisor

Surface texture:

a. Macroscopic = depressions, grooves, etc.

b. Microscopic = Glaze

c. Textured surface diffuse reflectance

d. Smooth surface specular reflectance

e. Vertical highlights = illusion of narrower, longer tooth

f. Horizontal highlights = illusion of wider, shorter tooth

Color:

a. Hue = Tint

b. Chroma = intensity of Hue

c. Value = Light and darkness (grayscale), if value is increased it gives an illusion of a larger crown. If value is decreased it gives an illusion of a smaller crown

Pros,11/12/01 7:58 am (Dr. Lindquist)

Esthetic limitations of the pfm crown...
strength limitations of PFM crowns....
Methods of strengthening dental porcelain...
currently available and experimentatl all porcelain systems...
- comparative studies of all porcelain restorations...

Return to the all porcelain crown....
manufacturers concstant;y trying to ,ake a better porcelain crown. They
are felt to be more esthetic than pfm. this is becasue of transfer of
light -- por. just looks a heck of  lot like enamel.

limitation of the pfm crown: a little less vbibrabt looking. Creates the
"metalceramic smile."

Light transmisssiona...

Light goes through ceramic much better than pfm.  Depth of translucency
is wat really matters, thogh.

some of the nwere all ceramics have a core material -- some of them are
almost as opaque as pfm! Something to consider...

Limitations of dental porcelain- weakness in tension
- brittleness
- pyroplasticity and sintering shrinkage

Weakness in tension
- concentration of stress at surface flawa (cracks)... griffith flaws
come about as a result of cooling. stress is concentrated at the tip of
flaws. glazing is meant to minimize this.
- corrocion fatigue

Concentrationi of stress at surface flaws
- residual stress = oral stress > crack growth > eventual catastrophic
failure
- limits tensile strength to 1/100 - 1/10000

"we masue by weakness at surface."  (/)

Corrosion fatigue
- chemical reaction of water and glass > crack growth and gradual
decrease in strength
- moist porcelain shows an immediate decrease in strength of
approximately 1/3
ask yourself how materilas were stored when they were tested during
studies that show porcelain qualities...

Brittleness
- the critical strain to fracture all dental porcelains is approximately
.1% (ium strain/1mm thickness of porcelain)... so it must be propoerly
supported. choose cases carefullly.

Proplasticity and shrinkage
- the sintering shrinkage and flow of porcelain at high temperature make
attainment of accurate margins difficult.  Any timne you heeat the
porfcelain, the glass structure moves. you never get that really sharp
lmargin like with metal.

Dental porcelain
- glass matrix

Strengthenin porcelain
- increase the modulsus of elasticity elasticit (stiffness)y
- decrease the effect of surface flaws

Campbell 1989 -- study on porcelain strength..

increasing modulus  of elasticity
- current methods achieve this va the enhances mechanical propoerties of
the crystalline phase

strengthening via the crystalline phase
1. dispersion hardening
2. enamiling to high strength profiles
3. controlled crystallization

The dillemma boils down to: strength vs. translucency.

Dispersion hardening (increase crystalization ratio)
- aluminous porcelain
- cerestore
- hi-ceram
- optec hsp
O'Brien (experimantal)

don't worry about brands, but know methods of strengthining.

Controlled Crystallizaition
- dicor (cast glass)
- CeraPearl

method for dicor: wax up, precerammed casting -- cerammed casting --
shaded crown. some say this is almost too translucent

Enameling to a high strength profile -- platinum foil is place upon
core. High strength core porcelain as a sub structure. and this core is
very strong.

Decreasiig the effectg of the surface flaws
- decreaseing frequency or size
- limiting crack propogation

problem -- the ceramic core is also susceptible to microcracks. you get
surface flaws on outside and inside...

decreasing frequency and size of surface flaws
- enamelling to metal foils
- fabrication using

enameling to metal foils....
- bonded platinum
- ? (didn;t get it)

refractory die material... very porous die material is used that soaks
up water. withstands high heat....


Limiting vrack propogation
- enamielling to metal foils
- dispersion hardening
- pre-stressing the surface (experimental)

Flexural strength: what is necessary?
anterior:
- 140-15- MPa (2.1% clinical failure rtae of bonded platinum aluminous
orr. incosor crowns over a 7 yr perios)
Posterios:
- 450-55- MPa

Summary:
Presently available all-ceramic crowns do not equal PFM crowns in
strength
Careful case selection is the KEY. usually anteriors are used for
all-porcelain systems.

study -- repoted mean flexural strengths... we need to know what
"system" we like to use the most... technicians are going to spend the
big bucks on a system, so they'll want to know what we are using.

different studies look at different aspects... hard to make side by side
comparison -- all studies have different materials, measuring
techniques, etc. But all studies havve a trend that boils down to this
-- once you get posterior to the premolars, your strength reqwuirement
is so much higherthat you need to be wary of porcelain.

Marginal adaptation: wat is clinicallly acceptible?
- 40um is the smallest detectable aginakl opening
- 120um is the max clinically acceptible marginal opening.

Summary: Margins
Marginal fit of newer porcelains is better than traditional pjc's, but
still not as good as pfm. All ceramics are getting a little better,
though...

Lab studies vs. clinical performance.... observed srength and marginal
fit is affected by: tooth preparation, fabrication variables, and test
conditions. All three of these thingsa re measures much better with
clinical performance studies. keep thatin mind.


Wide variationin strength and fit are ingerent fot eh all-porcelain
crown... therefore, ? (dind't get)

noe that some systems have very specific cementationi techniques... all
ceramicsystems all differ from wach other in terms of manufacturing,
srength, cementatin, etc....


THE BOTTOM LINE:
- case selection is critical
- prep design is critical, critical to mechanial success
- technical supprt from the labis critical.

--------------------------
project -- waxingtoday. check protrusives.... get embrasure and line
angle symmetry.

make a matrix based upon wax up. half a scoop weach of base and
catylist. this will guide you during cutback. regarding cutback, ou can
use a t3 or explorer. need a 1mm collar. In the end it will be
colarless.ceramometal jnction will be ust above lingula, in folla -- as
long as contact area is in ginnival 1/3. Collar format goes at least to
prox contact. take 1.5mm off inciasl edge. after taking incisal edge, do
dept uts facially of 1 mm. do same off prox and lingaul surfaces. eep
internalaspect nice and rounded. ceramometal jctino line is very
distinct.

wax cutback: looking for:
- uniform reduction (depth cutes -- incisal and axial)
- eval with matrix
- keep neat and smooth as possibnle
   - form rounded internal line angles
   - por/metal junctino is 90 degrees.
Barry Hillam
barry@hillam.net

Pros 11/12/01 8:46 am (Dr. Schneider)

Common Sense Evaluation of Currently Available All Ceramic Fixed
Restorations

Dr. Schneider has concerns with this stuff...

is all ceramic the new standard? (picture of woman with missing incisor)

all ceramics is a very hip topic.. but dr. s still has questions that
have not been answered yet.

Most esthietic failures with anterior restorations are a result of
immproper soft i=tisue mamagement rather than deficiencies in the
materials utilized in the restoration..

pfm advantages:
- good margins
- controlled occlusal contacts
- easily polished when adjusted
- good esthetics
- metal coping give s good spurrot and strength
- metal contacts minimize enamel wear. especially on posterioir .
 Porcelain wears enamel.

Advancess in PFM technilolgy tha have imporc=oved esthetics:
- inernal color addition
- segmental buikld up of various tooth colo compoents
- accurate all porcelain margin fabrication..  today we can get darng
good margins.

Many new all ceramic system (you'l be barraged with these) are promoted
for their high strength...

assming that streggtendn porcelains will result inimporoved clincal
performance lacks clinical valisity

with current techniques it is not possible to produce any ceramic
restoration without griffith flaws.

sekectin all ceramic stuff based on contrlolled clininal studies.

there is anl one  5 year study on all ceramic available .. "I'm not
goung to try stuff on patients -- show me the data.


all ceramic systems, clinical trials show that alll porcelains have a
faiklure tae of 33 % in posteriors.

it seems prudent, then, to keep all porcelains off of molars. Dr. S has
big

scneiders concerns for all ceramic restoratinos:
1. lab trials don't determine clinical performance.
2. controlled clinical trials are crucial -- there are almost none
3. all ceramics should not be used indiscriminately to restore
posteriorteeth and occlusion. -- show me the restoration in 5 years....
4. no all ceramic system provides inherently superior marginal
integrity.

procera: "you get perfect margins... how about them" they are only open
100 microns. that's stupid! that's way too open.

 5. alll ceramic sstems uutilizing refractory dies will be technique
sensitive unless each batch of refractory material is identical. ... any
system that requires rafratory type investmemnts: stay awa from it.

6. all ceramic systems as currentl =ty designed require more tooth
reduction than pfm's. prblem if small tooth to begin with

7. very tough to comensate for lack of ideal preparation.. all preps
must be based up and ideal

8. all types of porcelain will cause attrition of opposing dentition

9. currentlyinidicated  for single unit. no studies for bridges

10. optimal results are obtained with standardized procedures. systems
classified as technique sensitive will haea lack of predictably... these
are farfrom simple... too many variables to haver a million steps...

11. ther are no economic advantages with all porcelain... so why are we
doing it? for esthetics...

12. all ceramics are less biologicall active than those using metal
alloys.  so may be uselful for those with metal allergies. but this is
almost a non issue. Dr. S. has inly teated 1 patient with this.

13. if it hasan internal opaque core, the esthetics will be no different
(better)  than pfm.

14. pressables... when internal characterization isn't possible, you
have to colorize on external surace. in this case it will look
unnatural. color can wear off. they ca look liike a piece of chalk.

15. excellent esthetic results may be achieved by talented (not gifted)
technicians IF you give them enough reduction. that's their bigest
complaint

1

what is the status of these restorations after endo is done? lots of
times you can restore the acces with an alloy, and you don't have to
scrap th ecrown. you just can't do this with all ceramic... most of the
time the will explode. approx 25%  -- woops, 10-17% of all fixed
restoratioons will need endo therapy.


conservation of tooth structure determines long term rognosis  -- this
is a huge factor.

dr s. uses all ceramic, just not indiscriminately.

current litaruter ahows pfm lasting WAY longer.

conservation of toooth structure with preps is still an absolute
cornerstone

don't fall forall the stuff at trade shows, like about cad cams, etc...

go to back of jada. find what's for sale. you'll see cad cams for sale.
people always getting rid of them.

gold and alloys last decades (pics)...

case -- guy insisted on all ceramic. dr s. didn't wasnt to . patient
won. but it started to crack in 2 yrs...

a good technicial=n can match shade gide very well with pfm.

BOTTOM LINE:
patient selectin: bruxer, oclusion, pros design (long span, etc)
- prep design (critical to success fo all ceramic)
- technical support (should lab invest in it?)
Barry Hillam
barry@hillam.net

Pros 11/16/01 8:00 am

Ceramometal Restorations --  Framework Design

dentists will be designing framework. technician will be fabricated, but
YOU DA MAN.

ceramometal framework
- material properties
- anterior vs. posterior
-fpd considerations
- steps of fabrication
- evaluation

the framework gives the strength. the porcelain just makes it pretty.
connectors in the porcelain are critical.

you can't really evaluate framework when porcelain is on.

The ulktimate goals of the frameqork
- esthetics
- function
- predictable success. (on't want patient to ome back in a ear with
fractured porcelain -- they should last for a predictable amount of
time.)

who's in charge?
- the dentist?
- the labratory technician?

we design it, they make it. collaborate and agree re: materials,
fabrication methods.

Material properties
- Porcelain
- metal

base metal alloy. porcelain must meet coefficient of thermal expansion.

Metal properties
- metal choices
   - high noble alloy (what we use at the school - we'll use sf52 for
our project)
   - noble alloy
   - basealloy
- ceramometal bond
- pysalproperties

Porcelain properties
- strong im compression
- weak in tension
- brittle
- abrasive (where to put ceramometal junction?)

knowing these things efects youir design.

Framework COnsiderations
-support forporcelain
- marginal integrity
- framework rigitity
0 wear potentian
- final stess state
-
- esthetic conseiderations

Porcelain support
- por thickness shoul dnot exceed 2 mmm
- wrap porcelain
   - lingual surface of anterior
   - buccal cusp wrap of posterior

pic: bad prep. lost tooth structure. metal makes up for deficiency. ten
everyhing is okay. but if you g and try and stack more than 2 mm of
porcelain, the material fatiggues -- ou get micro cracks, and then,
**POW!** catastrophic failure!! Nobody wants that kind of anguish.

sometimes you may want to brin lingual all the way up in metal. nice for
strength, bad for esthetics.

avoid having ceramometal jnctn the same heightsh as incisal edge
support. too much potential for fracture.

Marginal Integrity
- Metal Margin
   -entire circumference of restoration
   - 0.5 mm or greater when present
- Esthetic considerations
   -disappearing margin
   - porcelain shoulder

know what accomodates what. shoulder bevel means ou must have collar,
for wxample. heavy chamfir gives you more options.

Framework Rigisity
- metal allo
- metal thickness (this is the usual culprit)
   - 0.3-0.5mm
   - dependent upon preparation
- Non-esthetic surface left  in metal
   - occlusal, lingual

east and west coast -- ou'll see very littel metal on pfm's. Only a
slight lingual colllar

flex=length cubed or 1/depth cubed
or 1/width

picture -- bad design

anterior vs. posterior -- the connector design is different according to
tooth shape. we compromise a little with lingual areas so  we can good
esthetics with facial (?)

Wear Potential of Porcelain
- evaluate overall occlusal scheme
- centric contact on metal when possible
   - location
   - opposing dentition

sometimes over time the porcelain ends up looking way out of place
becasue of how much the neighboring teeth wear...

putting contact in porcelain is smart if porcelain restoration is
opposing.

Final stress state of porcelain
- relatively uniform por thickness
   -avoid extrememly thin or thick
- round internal framework line angles
- minimize the number of surfaces veneered with porcelain
- butt-joint porcelain-metal junction
- Occlusal loas away from porcelain metal junction
we do a full contoured wax up so that we can get uniform thickness of
porcelain.

don't make the incisal edge point on the framwework.

Don't put occlusal contacts on the ceramometal junction. It should be
1.5mm away.

FPD connector design
- maximize occlusogingival dimensioin
- unencumbered gingival, facial, incisal/oclusal embrasures
   - esthets
  -perio heallth
- compromise lingual embrasures
- flex + length cubed (Etc, from above)

Lingual embrasures aren't as sharply defines as they would be in an all
metal restoration.

You can get frameworks back in the wax cutback stage... (You all go
ahead and do that...)

FPD cPontic design'
- appearance zone
 - modified ridge lap
   - illusion of tooth
   - convex surface
   - lingual deflective contour
- non appearcnce zone
 - bullet of conical

Anterior Restorations
- prox contacts not blocked by metal (so light can pass through)
- incisal edge not bloced by metal
- marginal design
   -disappearing margin
   -porcelain shoulder

badpic - framework contacts are in metal between central incisors. there
will be no transmission pf light...

understand (use book) how winged design plasinto this (?)

Post restoration
prox contacts - metal or porcelain
- full coveralge por
- marginal design

some people like prox contacts in porcelain on posteriors. In this way
it  is easier to to tweak contacts if ou want to change them.

Steps of framework fabrication
1. full contoured wax up
2. cut back of wax pattern (design framework
3. cast, and  if necessary,
 solder
4. try-in framework

you can have labsend back wax up and matrix so you can see if they did
fulll contour (then you can plant an ultra-small tracking device in the
wax so that ou can trace their every move when you send the wax up back)

"Finessing the collar..." (referring to the wax cut-back)

Evaluation of the Framework
- full contoures wac up
- cut back of wax pattern
- metal farmework prior to porcelaini application

Potential Ceramometal Failers
- Materials
   -metal
   -porcelain
- Oral Conditions (bruxing, etc)
- Improper famework design (picture: WAY too little pontic supprt in
framework

Physical porcelain fractures casues, reparing and prevention
- potential for fracture
   - resognize during fabrication
- before repair


Physical fracture casues
- thin metal substructure (thick enough, location, fx rewuirements)
- improper metal design...

(didn't get all of the last three slides)

"the ceramometal framework needs to satisfy all the esthetic and fx
demans,...."

Project-- matrix.....  draw framework design... do depth cuts. good to
use cleoid. takek small amoutns off at once. sharp ceramometal juncture,
but rounded intenal line anlges.

Wax cutbazck
- uniform reduction
- eval with matrix
]- keep neat and smooth as possible

Couple changes -- phosphate boded investments on monday. seniors need
benchlab ny 12:30 on monday. schedule -- december 21 -- id practical.
takes 20 min per rotation. that will be changed to dec 7, during class.
Barry Hillam
barry@hillam.net

Fixed Pros

11-16-01

Corrinn Cosaert

PFM framework Design and PFM Cutback

Phosphate bonded investments

Phosphate Bonded Investments

-used with alloys requiring casting temperature in excess of 2100

-Expansion varied by the proportions of silica solution in water

increase silica, decrease water = Increased expansion

-Gypsum bonded investment carried out over 2100 F have decomposition of calcium sulfate releasing contaminating sulfur in the mold. (silica solution is special solution we will be using with powder)

-Power Cast will be used with Power Plus Liquid

11ml of liquid and 3 ml of water.

-Completely wet powder by hand mixing 20 sec.

-Vacuum mix for 90 sec (b/c setting reaction will release gas into investment so takes longer to release all gas from mixture)

-Let set for 45 min (no submergence of investment into water) expansion controlled by proportion of liquid/powder we use

-1250 C oven---need about 45 min to an hour to reach 1250 burnout temp

-Heat soak for 45min at 1250C

-Crucible should be new (no contamination)

-Cast-let cool (DO NOT QUENCH-b/c might cause distortion, want it to be stronger and harder,

don’t want alloy to be in soften state)

-Remove investment (can use air abrasion)

-Remove internal positives

-Fit onto die

disclosing agent (occlude)

-Evaluate overall fit and marginal adaptation

-cut sprue off w/ a joe dandy

METAL PREPARATION

-done to prepare metal before porcelain is added

*pink stone---use for gross removal of metal

*green stone---finer details

make sure to use new set of stones so to

eliminate any chance of contamination

-use caliper before adjusting!

NEED INCISAL CLEARANCE OF AT LEAST 1.5mm\

Facial clearance -want thickness of metal to be .3mm to have at least 1.2mm porcelain

Metal Finishing

-Finish in one direction

Mesial-Distal---never ever ever overlap direction of finishing

Pick a direction and stay with it

Prevents overlapping of metal and trapping contaminates

Reduce metal to

.3mm for HIGH NOBLE METAL

.2mm for BASE METAL

metal surface should be smooth with a satin finish this can be achieved using green stone

Framework necessities

Develop rounded internal line angles

Create distinct metal-porcelain junction

Reduce metal collar to desired thickness

Disappearing margin

.5mm is the smallest collar for polishing (it can be larger depending on location)

REVIEW OF INVESTMENT MATERIALS by Clark Stanford

This lecture was a review of a previous lecture on 3/21/01. IF by chance you can’t

Find yours you can copy mine.

Pros objectives

I compiled these from book, old notes, and old objectives

1. Know and understand the first step in a well designed PFM framework

Can only be achieved by waxing to full contour the restoration and then cutting back

the correct amount of wax so that there is an even thickness of reduction allowing

for even thickness of porcelain application, good connector design, and optimally placed occlusal contacts.

2. In a PFM framework how do anterior and posterior designs compare in relation to: proximal contacts, connector designs, wrapping over onto occlusal/lingual surface, marginal design?

Anterior

-Proximal contacts are both in porcelain allowing for max esthetics.

-Winged -minimizes the amount of translucency in interproximal area

-Wingless-better esthetics

-Connector design- narrower buccal lingually than posterior, there for

maximize occlusal gingivally (connectors should be placed so they do

not impede on oral hygiene, lingual embrasures may be compromised at times

to allow for max esthetics)

-wrapping over occlusal/lingual surface for anteriors-the design of the lingual portion is very much dependent upon the dentition that is opposing the restoration.

-Make sure that your centric contact is 1.5mm away from the metal/porcelain

junction.

Posterior

-Proximal contacts -mesial in porcelain while distal in metal (a distal contact

In porcelain allows for a more conservative tooth preparation)

-Connectors

This is directly from book pg 496

If only a facial veneer is involved, make the connectors identical to those for a conventional restoration. If the incisal or occlusal aspect is involved in the porcelain veneer, don not displace the connector cervically, because access for oral hygiene will be impeded.

3. What is the relationship of the occlusal contact to the metal ceramic junction?

The occlusal contact must be 1.5 mm away from the metal ceramic junction or else

Porcelain FRACTURE.

4. How does the porcelain stress state relate to the number of surfaces covered with porcelain?

Covering more surfaces in porcelain is going to increase your stress state and lead to fracture.

5. What is the optimal thickness of PFM coping (wax vs. metal)

Wax: .5mm thick so that you can get proper casting as well as most of the necessary reduction for adequate porcelain addition.

Make sure to reestablish the collar before investing to about .5mm thickness to ensure an undistorted complete casting.

6. What are the purposes of a full contoured wax-up?

-to arrive at a substructure that will support a relatively even thickness of porcelain

-If the retainer is to serve as part of a FPD it must allow for proper connector configuration

and location

-The restoration must conform to the normal anatomic configuration of the tooth that is being replaced.

If this technique is not followed your bound to screw up : ) But we’re all used to this because it’s pros which by very definition means your bound to screw up somewhere along the line meaning you’ll have to start all over again! Oh, no, I’m not bitter.

7. Optimum porcelain thickness in the PFM restoration

1mm at cavosurface margin (heavy chamfer)

axial reduction so that 1.5mm of porcelain can be added.

Incisal edge reduction of 2.0mm.

8. What design considerations should be taken into account with a PFM long span FPD?

(the following is from the book pages527-528, 535

There are many things to be considered when making a long span PFM FPD one of which is

MECHANICAL

Long span FPD are inevitably susceptible to mechanical problems

(Remember Law of Beams that the amount of flexure varies inversely with the cube of the depth, and directly with the cube of the length)

Metal Ceramic FPD are more susceptible to fracture but with adequate

Framework design and porcelain thickness they can be successful.

-need at least 1.2mm porcelain thickness ( if too thick then it can lead to fracture)

-make sure that the metal surface is free of pits and irregularities

this helps prevent incomplete wetting by the porcelain leading to

voids at the porcelain metal interface that reduces bond strength and increases

the possibilities of failure

-sharp angles need to be rounded

-the location and design of the centric contacts requires

1.5mm distance from metal ceramic junction

excursive contacts must be watched closely.

FPD pontic design

Anterior appearance Zone -typically use the modified ridge lap pontic

Non-appearance Zone-Typically use a bullet or conical pontic. Can’t

Use hygienic pontic with a PFM FPD because you don’t have enough

Room for all the material.

Advantages of PFM FPD

-esthetics and Biocompatable

Disadvantages of PFM FPD

-Difficult if an abutment is not metal-ceramic

-weaker than all-metal

Indications

-Most situations

Contraindications

-long span with high stress

9.What factors are considered in relation to occlusal contacts?

Metal contacts are preferred because less abrasive to opposing teeth, can withstand more stress than porcelain, can adjust contacts if needed.

Make sure that all occlusal contacts are 1.5mm away from ceramo-meatal junction.

10. Know and understand what framework design feature help to decrease the stress state of Porcelain.

-Rounded internal line angles

-Adequate, uniform thickness of porcelain as mentioned above

-Porcelain thickness not to exceed 2.0mm (If you have a tooth with a lot of reduction

you can make up the difference in the metal substructure. )

-Occlusal contacts at least 1.5mm away from Ceramo-metal junction

-Metal should be smooth without pitting so that the ceramo-metal bond is

maximized

-Need at least .5mm of metal for collar design inorder to be able to adequately polish

the metal.

-limit number of surfaces with porcelain

-90 degree butt join at porcelain metal junction.

11. What factors are necessary to optimum esthetics?

Student Notes

Fixed Pros

11/26/01

Nicole Eberle

Porcelain Application

1^st step = oxidation cycle in the oven. Holds the temp for 5 min in order to oxidize the surface to bring up trace metals to the surface so that it will bond with the porcelain.

Opaque = off-white/egg-shell

Pink=body

Incisal=white (used on middle to incisal 1/3)

Stains/modifiers applied externally after have everything fitted and shaped the way you want. This is the last and final step before finishing metal.

Body makes up most of the crown surface. Incisal goes mainly on middle to incisal 1/3, has a gradual transition. Modifiers can also be placed internally, which makes the tooth look much more vital. We will be placing stains externally. Can use the stains in clinic too.

Opaque

Creates 1^st metal-porcelain bond

Masks color of metal/grayness

Primary source of color for the crown (many colors go together to create color chosen on the shade tab)

Should not exceed 0.1mm (therefore do not need a lot of opaque to mask metal and create bond)

Make sure metal prepared to 0.3mm, especially on facial. May have more on incisal, interproximal, and lingual depending on what prep looks like, but try not to exceed 0.1 with opaque.

Clamp lingual collar of framework with hemostat after metal prepared with green stone (final step). Then sand blast, steam clean to rinse, then ready to go into oven for oxidation cycle. Sandblaster should take less than 30 sec and want to keep moving around as not to perforate the framework. Do not touch coping with fingers (even with gloves) after sandblasted because fingers have oil and gloves will contaminate surface. Sagger tray (ceramic tray) used in porcelain oven. Pillow put on tray and coping put on pillow and tray put in oven. When comes out of oven, grab coping with hemostat. If you oxidize, you need to put on at least one layer of opaque. Other layers can do one at a time and leave it. Put opaque on glass slab. Two different liquids can be used to mix porcelain: 1. distilled water, 2. special modeling liquid (primarily water with a few extra ingredients that make the water evaporate a little slower) Both do the exact same thing, no problem using either one. Mix till it flows fairly easily. As long as you keep clean, can reuse powder mixture if you add water. Once oxidized, framework has a little more charcoal color. Number of ways to apply porcelain to framework: 1. glass instrument, 2. sable brushes (#1=small, #6=large). Place thin layer of opaque with #1 sable brush. Make sure coping is cool when place opaque, otherwise water will evaporate too quickly and you can’t move opaque. If blotchy, even out opaque by tapping with another instrument. Will not necessarily get full masking of metal with 1^st layer of opaque. May need 3 layers to completely mask. Judge this after porcelain has been baked in the oven. Do not just set hot Sagger trays on plastic or will melt. Ovens normally run in night mode. Low glaze better for us for glazing step. Need a dry time for each layer of porcelain, and this is programmed into the oven. Can reuse brushes, just rinse them out. We will use the same brushes for the stain. Should have egg shell texture when opaque comes out of oven. Want to mask grayness of metal with opaque. Use same glass slab for body/incisal porcelain. Use small and large brush for this.

Body

Provides basic color of restoration

May shrink as much as 20% of their volume during 1^st firing, so tend to overbuild just a little bit to compensate (this has to do with how well you are condensing the porcelain)

Incisal

Enhances translucency of restoration

May shrink as much as 20% of their volume during 1^st firing, so tend to overbuild just a little bit to compensate

Incisal put on over body to enhance esthetic result. Put coping on working cast now, then place porcelain. After opaque, now can handle with fingers, but keep it at a minimum because want to try to keep it as clean as possible. Want tissue handy to control water adding to porcelain. Want more consistency with body and incisal than with opaque when mixing. When tissue placed next to porcelain it will absorb to get to right consistency. Also want new Bard Parker blade and cup of water to rinse brush off as going through the addition process. Dr. L likes to wet the surface 1^st before she adds porcelain. Holding tissue behind helps absorb some of the water. Build up a general shape. Not worried about interproximal contacts at this point. If too much liquid, the porcelain will slump pretty easily. If dry, can’t move it around and it’s hard to blend in. Use large sable brush to shape. Add body and incisal at the same time to get a better blend. Incisal primarily in incisal edge and interproximal. Use Bard Parker to take off incisal edge and to bevel toward the facial aspect to get gradual transition from body to incisal from middle to incisal 1/3. Also take some out of interproximal area. Gently wet porcelain 1^st then add incisal. Smooth it out with a brush. Use tissue to absorb some of the water. Need to take off of working cast to get proximal contacts. Grab with hemostat on lingual collar. Work with it initially on working cast to get F-L and I-G aspect of incisal edge. Shape a little bit with brush in general so looks like well rounded porcelain anterior crown. Take small wet brush to wipe away excess porcelain at metal-ceramic junction so porcelain is not overlapping. Also be sure there is no porcelain internally, because can see it now, but will not see it be able to see it after you fire it (esp. incisal porcelain). Vibration condensing - condense for a few minutes, but be sure to take water off with tissue as soon as it comes to the surface. Do not tap so hard that all the porcelain slumps. It you keep vibrating this, it will gradually turn into a little ball. More than one crown can go on a pillow. After 1^st bake, it has a chalky look to it. We will not going to be looking at the quality of the porcelain or the color of the porcelain, we will only be graded on contours and embrasures. Usually, after it comes out of the oven, will not go into place. Mark interproximal contacts with marking paper, then shape with green wheel. Adjust incisal edge after have adjusted proximal contacts. Can draw on porcelain Not unusual to add porcelain in more than one bake. To do this, hold with hemostat on lingual collar, then sandblast and steam clean, then add more porcelain. Once everything is all shaped and clean, experiment with putting surface texture in (horizontal and vertical). Stain and then put in final glaze cycle (low glaze). Stains will be premixed with glycerin. There are different hues and different levels of chroma to practice putting stain on. After final glaze and not touching porcelain any more, then polish metal collar on lingual. After porcelain completed, use small green stone to identify ceramo-metal junction so no flash of porcelain over 90 degree butt joint. Then go over same polishing sequence as you do with full cast crown.

Fixed Pros

11/30/01

Mike Franzman

Factors influencing Esthetics

Tooth and embrasure form

Surface texture

Color - it is harder to detect problems with color (the eye is less discriminating with color)

Tooth size

Preparation and fabrication variables

Tooth and embrasure form and tooth size are the easiest to see when there’s a problem.

Color is generated by waves of electromagnetic energy - there is no such thing as an exact color match, only a limited range of acceptable variability.

Energy Distribution x Reflectance x Response = Color Stimulus

(more reflectance with natural teeth)

Factors involved in final color: light->modifier->observer (eye)

Dimensions of Color - These three allow you to communicate the color you want in the restoration:

1. Hue - The quality of the color determined by the wavelength.

2. Chroma - The concentration, intensity, or strength of the hue.

3. Value - The relative whiteness or blackness of a color (grayscale) - the most challenging aspect of color.

The Munsell Color Notation: A color wheel that is good for color comparisons. Chroma and value tend to have greater spectrum of variability than hue.

The Vita Shade Guide: used in clinic. There is not enough material out there to match the variability we see in teeth clinically.

Shade Matching

1. Clean tooth to be matched - pumice first, don’t dehydrate the tooth, do the shade selection at the beginning of appointment.

2. Select guide tab based on general appraisal of value of hue. Hold the whole shade guide up to the teeth to pick the right tab range.

3. Moisten the tooth and guide tab, hold it in direct apposition (same plane) as the tooth you’re looking at.

4. Squint to appraise the value - rod cells in the eye are used for this and squinting facilitates their use.

5. Appraise the hue - is the tooth more yellow or red? (this is the range of tooth colors yellow to yellow-red)

6. Appraise the chroma - is it more intense (gingival) or less intense (incisal)?

7. Limit viewing to 5 second spurts, use a blue card (or coat) to look away because rods and cones tire very quickly. (Remember the flag example she used?)

8. View female patients (or male if they’re into that…) with and without lipstick.

9. Use multiple light sources - different hues can be given by different light sources, this is called metamerism. A partly cloudy day is the best source.

The spectral curve measures the apparent color temperature. It is a color rendering index. (?)

10. Use the shade guide recommended by the porcelain manufacturer.

11. If modification is possible, pick a shade higher in value and lower in chroma.

When you stain a restoration it decreases the value and increases the chroma.

12. If modification is not possible, pick a shade lower in value (so it won’t stand out in the mouth)

13. If you use modified shade guides, submit the guide tab to the laboratory.

Final step of shade:

Communicating the color appearance to the dental lab.

Accurate shade matches begin with adequate tooth reduction.

We need:

Framework 0.3 mm

Porcelain:

Opaque 0.3 mm

Dentin (body) 0.7 mm

Enamel (incisal) 0.2 mm

Essentials for color prescription:

Proper shade selection

Shade reference to a specific tab (guide)

Enamel/Dentin blend

Color characterization

-reference to a specific stain

-placement (draw a picture for the lab tech)

Completing the prescription:

Surface Characterization - allows the restoration to blend in with natural teeth

Glaze - high, medium, or low

Patient information - young person, old fogey, where’s their smile line?

Color is ambiguous (so is Fixed Pros) - People see colors differently

Value:

Decreased by:

Applying a complementary hue

Applying brown

Using a lower glaze

Increased by:

Applying yellow

Applying white

Using a higher glaze

Stains:

1. Lower the values

2. Give metameric responses.

Color selection and matching is a learned process - we must practice.

Fixed Pros. Student Notes: Monday, 12/3/01

Bob Fuhrman

Work Authorization (Dr. Lindquist)

Identify tooth

Shade (ie B3) and type of Guide used (ie Vita)

Serial # of articulator

Condylar inclination: R= 30, L= 30

Bennett angle: R= 0, L= 0

Type of Pontic if FPD

Example: Please fabricate PFM restoration for #5. The master cast is mounted, die is trimmed with margins marked in red.

--Please wax #5 to full contour using adjacent teeth as guides.

--Cutback for porcelain

Create disappearing margin on facial (with a collar, you need it’s dimensions)

Mesial contact in porcelain, distal contact in metal

Porcelain-metal junction should end 1/2 way down lingual incline of buccal cusp. Establishing centric contacts in metal. No lateral excursive contacts (or Protrusive)

Cast in High noble ceramo-metal alloy (SF52), fit to die

****Option: Coping/Framework try-in - this is especially important.

Single units vs. FPD - may need to section and solder

If working with a new lab

--Prepare metal for porcelain and apply Vita shade B3

--Shape porcelain using adjacent teeth as guides

Options: 1) Return at bisbake stage

2) Return stained and glazed with metal polished

--Draw a Picture

Lab Communication: (Todd Fridrich)

Why is it essential?

1) We are constantly exposed to new materials and technologies

2) We provide complex dental treatment

3) High esthetic expectations are demanded by patients

Enrollment: only 34 Dental Technology schools now = fewer skilled technicians. Enrollment has been down 66% in last 25 years, and down 25% in last 5 years.

Don’t bitch at technicians…they don’t know why you want the restoration made a certain way, they only make it!

Labs do not want to stop the production line! In a big lab, if you don’t specify shade it WILL be A2.

DDS wants:

Quality product

Good esthetics

Consistency

On time delivery

Lab wants:

Good impression

Completed work authorization

Adequate working time (1.5-2 weeks)

Timely payment

Write a MEANINGFUL work authorization! It is a legal document that could save your butt in court or be incriminating against you.

Work authorization should include:

Restoration type and tooth #(s) - scroll this right into the impression too

Procedure, check steps that you want see the restoration returned before final finished product

Margin design (even implants have margin designs)

Esthetic margin options: deep chamfer - good for an all purpose, porcelain margin. Deep shoulder - for a porcelain butt margin.

With the Procera porcelain restoration system, you need to use a diamond the size of the probe which scans the prep. (This was a huge probe next to the tooth.) Bad - no one wants to use this type of diamond to cut a prep.

Framework design - easier to see when porcelain is not on. If framework is too thick, porcelain will be too thin. Have a metal collar on the lingual, and a metal occlusal surface because this is stronger and easier to adjust in occlusion. Want and even thickness of porcelain for color and strength.

Occlusion, Guidance - put patient in progressive group function if you know they will wear down their teeth. Want a balanced occlusion if you know dentures are involved.

Shade and characterization - best if you can provide ONE shade tab to the lab technician. Now we use ceramics to match/replace gingiva too. Make sure to compare the completed restoration to the shade tab AND the written lab authorization

Personal Information - Franzman’s mom or whomever gets it

Slides and photos do give helpful characterization information regarding the teeth and gingiva, but they cannot give shade information

Make good provisionals! They will build your practice. The work authorization goes hand-in-hand with a good provisional . . . make a crappy provisional, you hurry lab tech to get restoration done because provisional looks so bad . . . you get a crappy restoration back!

Improving Communication:

Establish an open line of communication

Relate on a personal level to technician

Encourage and initiate input - Technician has a mortgage, kids, etc. . . he won’t tell you you’re doing things wrong. You must contact Technician for info!

Don’t let small problems become BIG problems - work as a TEAM

Provide constructive criticism to Technician

Compliments when appropriate (Mr. Fridrich likes to be stroked. . . Franzman?)