1. CAD/CAM

Question 1

• This paper talks about the evaluation of ____, which is the most important thing in prosthodontics.
• In this article they had a group of people to make preps on acrylic teeth. After collecting all the preps, the divided
them into to 4 groups. ◦Excellent, Fair, Good, Poor
• Then they scanned them with two different cad/cam systems and made crowns with both of them.
◦____ system: 1st cad/cam system from Germany
◦____ system: also from Germany
◦The average of the marginal gap for both is about the same 81-82 so there’s not differences.

Answer 1

marginal fit
CEREC
PlanScan

Question 2

Preparation quality has a significant impact on ____ regardless of which system is used.
No significant difference was found when comparing the systems to each other.

Answer 2

marginal gap

Question 3

• You can see the marginal gap on the table
◦Poor quality preps is really bad, > ____ microns of marginal dis-adaptation
◦Excellent quality preps marginal adaptation is about ____ microns and that’s pretty good!
• Take home message
◦For cad/cam dentistry we need to provide high quality preparations (clean, smooth, detailed) with whatever
system you’re using to get the best result. Because at the end, technology won’t compensate for the low quality of dental procedures.

Answer 3

100

36.6

Question 4

What is CAD/CAM?
• CAD:ComputerAidedDesign
• For every clinical cad/cam system you will have:
◦an ____
◦____
◦____
‣ where we design the dental restorations • CAM: Computer Aided Manufacturing
◦we will be manufacturing the desired restoration (inlay/only, veneer, crown…)

Answer 4

intraoral scanner
PC
software

Question 5

When working with cad/cam technology we need to understand that this is a ____ technique.
• This means that the material that we have come in single small blocks of ceramic, like a square bubble
gum. Once we put this in the milling machine it will be milling out from the block until we have the final restoration.

Answer 5

substractive

Question 6

So is this a substractive or additive technique? Substractive
◦In the milling unit we have diamond burrs, similar to the ones we use with our hand piece.
‣ They have a width and a length
‣ In our preps we have very sharp angles, very thin and narrow edges. So the burrs from the cad/
cam system won’t be able to mill completely and in an smooth way the intaglio (inside part of the crown) so two things can happen
• if it’s not milled completely the restoration won’t seat totally
• But softwares are helpful and they will compensate for that and they will o____
crown fits
◦software helps us to remove more so we end up with a narrower and thinner crown so
can fit completely but makes it prone to fractures.
• That’s why we need very nice detailed tooth preparations

Answer 6

overmill

Question 7

Fatigue resistance of ultrathin CAD/CAM complete crowns with a simplified cementation process


Posterior crowns:
At the bottom of the fissure: at least ____ mm
In the area of the cusps: at least ____ mm
Circumferential: ____ mm

• As you learn more about dental material, you will see that each material has its own specific rules.
• For example
◦Some materials need a minimum thickness of ____ in the central fissure, or 1.5 in the cups. ◦When we are talking about full ceramics we need finish line, a circumferential shoulder minimum
____.
• So we need to understand these materials to be able to provide the software with appropriate
preparations depending on the material that we will use. Either for full or partial coverage.

Answer 7

1. 0
2. 5
3. 8-1.5
4. 0
5. 8

Question 8

Fatigue resistance of ultrathin CAD/CAM complete crowns with a simplified cementation process


Onlays:
At the bottom of the fissure: at least ____ mm
In the area of the cusps: ____ mm

Answer 8

1. 0

1. 5

Question 9

Prep Check

• Prepchek is a software that will help you self-evaluate your work.
• So you prep the acrylic teeth, scan them and then ____ your work against the ideal prep.
• If you’re off, it will tell you where you’re off
◦for example if you’re off in the parallelism or the shoulder finish line or the intraocclusal space
• Depending on the material we select, on the software it already knows all the needs of that specific ____
____.

Answer 9

self-evaluate

material

Question 10

Comparison of the marginal fit of lithium disilicate crowns fabricated with CAD/CAM technology by using conventional impressions and two intraoral digital scanners

Clinical implications
____ intraoral impression techniques can be a viable alternative to conventional impression methods

• So if we’re good, detailed and clean we can use conventional impression material successfully and
digital intraoral scanners successfully as well.
• Without that good detailed work non of them will work.

Answer 10

digital

Question 11

The workflow

We’re going to first talk about the CEREC software.
• ____ is the pioneer of the chairside cad/cam dentistry
• It was developed by dr. Moorman in university of Zurich 33 years ago
• This is a software that is very intuitive. You can see the small pictures meaning what we’re going to do
on the 5 phases. So we will go through each of these phases.
• These are the same thing that you do in a conventional work but now in a software

Answer 11

CEREC

Question 12

Video #1: ____ phase
• open CEREC software —> desktop view —> double click on CEREC software
• Add new patient and case information
◦we need to protect identities so only initials of last name and first name of patients
◦Add Axium chart number of the patient to locate that patient • Select restoration type
◦for ex. Single crown, multiple unit, implant…

Answer 12

administration

Question 13

Video #2: ____ phase
• This is where we will make the ____
• what you see here is the camera view always being preheated. This is heater.
◦this sits in the unit and it’s already preheated so when you go inside the mouth with body temperature, it will not get foggy
• so first thing you do when you get to your patient, connect the scanner, turn it on so it starts preheating

Answer 13

acquisition

digital impression

Question 14

Video #3: ____ phase
• Now the software is going to create those 3D models
• In this case where he has a maxillary prep, he needs a very detailed and clean scan of the maxilla, the
lower is more of the buccal and incisal/occlusal areas in order to have the correct occlusion.
• You need to get the bite registration in the area you need so the software can do the stitching
◦for example if you’re prep is number 8, don’t get buccal bite registration in the molar area
• ____ means finding those same spots in those different files and putting them together

The ____
• for the latest CEREC software we don’t need to do this anymore.
• Do things as the software instructs you
The ____
• with me or two clicks you can detail the margins. Rotate he model and see it from different views to
detail the margin.
• Disadvantage : working on flat screens
◦so always rotate and rotate to be able to see the margins from everywhere • Advantage: flip it and see it from the inside and intaglio surface

Answer 14

model
stitching
virutal articulator
automatic margins

Question 15

Video 4: ____ phase
once done with the model phase, design Panasonic will give us a ____
• they used to be ugly proposals that needed a lot of work but now the initial proposals are quite nice.
• Very symmetric, to the contralateral tooth
• There are different design modes which he will explain in detail later

Answer 15

design

proposal

Question 16

Video #5: ____ phase
• in milling stage consider the size of the restoration and select a block that actually fits the crown inside that block. The software will stop you from using smaller blocks than needed.
• We have ____ sized of blocks
• If you use the ____ possible block, you’re going to save time because the milling unit doesn’t need
to grind so much.
• Polychromatic blocks: the three layers of shade looks like flag
◦they have more ____ and more translucency

◦So depending on where you want to place the restoration we can customize it.
◦Initially all the blocks were single shade but nowadays we have all different values of shade • this takes about ____ minutes per restoration.

Answer 16

mill
different
smallest
saturation
10

Question 17

This is the first crown they did at penn with CEREC system on a patient in the honors clinic.
• They had this prep ready and had conventionally waxed up and made the provisional restoration.
• First thing they had a ____ around the prep.
• How good are the intraoral scanners when you are close to the tissue, have bleeding, have saliva and
when it’s subgingival?
◦The don’t work very good as conventionally materials don’t work as well ◦You need to have control of ____ in the quadrant you’re working

Answer 17

retraction cord

bleeding

Question 18

Administration phase
• select \_\_\_\_ ◦single unit
‣ crown
‣ Inlay/onlay ‣ Veneer
‣ Missing
◦Multiple unit ◦Implant

Answer 18

restoration type

Question 19

• In the design mode you have 3 options, this is important

◦Biogeneric individual **
‣ we use this for ____% of the crown and restorations, when we don’t have a ____ or an initial ideal pre-op situation we just select this option.
‣ The software then by ____ will design something that is customized for that patient (the prepped tooth, size of the preparation…)

◦Biogenreic copy
‣ Basically just ____
‣ Copy the shape of a provisional restoration and paste it in ceramic, just replace the material
while the shape is already the same.

◦Biogeneric reference
‣ For example When you’re doing number 8 but number 9 is ideal and intact (no wear, mo
restorations)
‣ So you tell the software to mirror image number ____, to cop it and rotate it for number 8

Answer 19

90
wax up
calculations
copy paste
9

Question 20

Acquisition phase
• make sure you have the scanner turned on a few minutes prior so it’s ____.
• Recall the three catalogs on the bottom that he talked about during video, but here we see four:
◦____
◦Lower
◦____
◦Bio copy
‣ an additional catalog in which he’s going to make the scan of the situation that he wants to copy.

‣ So the patient had a very nice provisional restoration for a few weeks that was not breaking or was not high, it was good in occlusion and contours. SO before you remove it you can ____ it here in the bio copy

Answer 20

preheating
upper
buccal

scan

Question 21

For a single unit you don’t need a full arch scan, you can do ____ . If anterior you can do the ____. This is the scan after cleaning it and cutting what you don’t need.

Answer 21

quadrants

sextant

Question 22

The opposing jaw is usually a quicker scan.

You want to capture all the ____ surfaces and the ____ for that relation with the buccal bite.

Answer 22

occlusal

buccal

Question 23

When you’re doing the buccal bite on the latest versions, we have green check marks. When the information is enough and the software already has the info to stitch, we see the ____ check and we stop, we won’t need any more information.

It is important to capture some ____ in lower and upper to be able to stitch them properly.

Answer 23

green

soft tissue

Question 24

This fourth scan, in this case that we’re doing the biogeneric copy is the scan of the provisional restoration.
You see a ____ image in the back, that means hat the software is superimposing or stitching this fourth catalog the upper jaw so everything is aligned together.

General Notes
• As he showed in the video (anterior scanning) , we always want start on the ____. You want to have
an ____ point, a starting and finishing point, and ____ point to the scan.
• Sometimes we can get too distant, too far away from the area that the scanner won’t keep scanning. We
need to go back to that anchor point.
• For Anterior teeth best anchor point would be ____.
• For Posterior is best anchor point will be ____ surfaces.
• ____ movements with the scanner are better. Slide toward buccal and go back again, rotate toward
lingual and go back again (45 degrees).

Answer 24

ghost

buccal
anchor
entry

buccal
occlusal
straight

Question 25

Model phase
• this is basically placing the model. Trim as you’d trim your die. Nowadays this is done ____ but we still have the steps if you want to do it.

Answer 25

automatically

Question 26

Draw margin
This is the key part of the whole model work. We need to determine the margins.
This is something that the ____ should do not the lab technician. Because we were the ones prepping the tooth. We know exactly where we want the crown to fit and seal.
So this is ____ step for the clinician

Answer 26

clinician

mandatory

Question 27

Preparation analysis

For Example: we have distance to antagonist
• we want to see if the distance to the opposing teeth is enough. How?
◦with a ____ bite and measure it
◦ But if you find a spot that you’re missing and need to go back and re-prep you don’t know exactly where that point it. So we usually ____ more than needed.
◦He’s going to show us how easily these areas are detected on the software on next slide.

Answer 27

wax

prep

Question 28

You see the colored scale on the top left.
Red:
• means that the minimum intraocclusal thickness is not ____ . That why the ____ will break. We don’t want have anything in red. So if you have an under-reduced area, you will see it red & will adjust.

Blue:
• Means that it’s okay, it’s enough.
• If we have everything blue we’re ____.

Green:
• Is going more toward 4 mm that is quite a ____.

Answer 28

adequate
crown
good
lot

Question 29

Preparation Analysis

Undercut
It’s very easy to make an undercut
we have another color scale for undercuts. ____ = undercut
• we don’t want undercuts, go back and fix it. Blue = ____ microns of undercut
• That’s basically ____
• When you design your crown it has a spacer which has an average of 100 microns. So 10 microns is not
a big deal.

Answer 29

undercut
10
nothing

Question 30

Preparation Analysis

Margin

Third tool is the margin and this is the most ____ tool.
• we need to have thin diamond burrs
• Need to be very detailed when we prep
• hand instruments work as well.
• Ultrasonic diamond tips that are not rotary, only ____ will help you to get a smooth margin.
• if margin is irregular the diamond burrs of the milling machine won’t be able to ____ that shape of
the margin.

Answer 30

challenging
vibrate
reproduce

Question 31

Preparation Analysis

Surface

• When we work on full ceramic is different than PFM. We want to have softer transitions, a preparation that flows.
• We don’t want to have too many ____ angles. Everything needs to be a little bit more ____ when we do full ceramics.
• If you have any sharp areas, ____ color will appear.

Answer 31

sharp
rounded
orange

Question 32

Design

Tools

Here’s an design of the crown. It’s the exact same copy of what they had on their provisional restoration. Here you can see the strength of the contact points. The color of the contact should be always ____ or ____.

We never want a yellow or ____, they are ok heavy and it will be ____. Remove them so you minimize the grinding of your ceramic which is always detrimental.

The nice thing is that you can ____ the contact of the adjacent teeth with the opposing arch. As a rule you don’t want to have any ____ contacts on your restorations compared to what you’ve got on the neighbor teeth.

Answer 32

aqua
green
red
heavy
activate
stronger

Question 33

Dental Ceramic Classification

• Silicate ceramics:
feldspathic ceramics
are the most traditional, they’re nice & esthetic but not so strong. They’re ____. ◦mostly used for ____
◦For ____ or crowns
‣ when the shade of the abutment is very natural, dentin natural color. Because these are very
translucent.
◦Contraindication: If you have an ____ treated tooth with a metal post or severe ____,
feldspathic ceramic won’t be good choice because you will see through the discoloration.

Answer 33

brittle
veneer
endo
discoloration

Question 34

Dental Ceramic Classification

Lithium silicate ceramics:
• these are also silicate ceramics but have ____.
• Lithium disilicate material is called e.max
◦this is the gold standard of ceramic materials bc
‣ it has different levels of ____
‣ you can ____ and bond it to the tooth very well
‣ And it’s very ____. ____ bonding it will also reinforce it
‣ Used a lot with cad/cam at PDM
◦newer versions of sodium disilicate is ____ reinforced silicate: no clinical data, new, not used at PDM

Answer 34

reinforcements
translucency
etch
strong
adhesively
zirconia

Question 35

Crystallisation and Stain/Glaze Firing

The E.max block has ____ written on it (previous slide). That’s the shade/color. But it looks purple bluish because when we mill the material it’s not in its ____ state. You need to heat it and crystallize it so the material will grow, transform, get stronger and get its final shade.
The crystallization process for emax takes about ____ minute and few minutes to cool down so ____ minutes.

Answer 35

A3
final
25
30

Question 36

We use emax because it has a success rate of ____ % up to 10 years so it’s proven to work very well.

Answer 36

96.7

Question 37

Emax can be used for the following:

• ____, veneers
• anterior and ____ crowns
• ____ supported crowns

Answer 37

onlays
posterior
implant

Question 38

This is the final crown that they’re delivering. This is made by us here. Everything is done on the same appointment. No need to send to ____. If we have a smooth detailed information to provide to the scanner the milling unit will be able to reproduce it as well and we’ll get a nice marginal adaptation.

Answer 38

lab technician