Digital Impressions and CAD/CAM Restorations Flashcards
(44 cards)
1
Q
what are 2 in vitro studies conducted by the dental advisor?
A
- biomaterials
- microbiology
2
Q
what are 3 clinical marketing studies conducted by the dental advisor?
A
- restorative materials - placement and long-term
- infection control products
- equipment
3
Q
describe 4 of apex dental milling’s products
A
- full-contour zirconia - anterior and posterior
- zirconia frameworks and copings
- pressed lithium disilicate
- printed orthodontic and C&B models
4
Q
what are the 6 main factors that need to be considered in selection of digital impression systems
A
- type of restoration - silica-based ceramic, zirconia, resin ceramic, metal, provisional, wax pattern
- in-office milling or milling center
- cost of equipment - $10,000 - $125,000
- powder required
- ortho and implant integration available
- special features
5
Q
what is CEREC?
A
- in-office milling system owned by DENTSPLY
- 3 types: APOLLO DI, BLUECAM, OMNICAM
6
Q
what are the major in-office milling systems?
A
- CEREC
- e4d Dentist (Planmeca)
- PlanScan & PlanMill 40 (Planmeca)
- TRIOS Pod and TRIOS Color (3Shape)
- Galaxy BioMill (BIOLASE)
- CS 3500 & 3600 intraoral scanners and Cs 3000 Mill (Carestream Dental)
- 3M True Definition Scanner (3M)
- TS 150 Mill (Glidewell Laboratories)
- Whip Mix Corporation
- DWX-50 Mill (Roland)
7
Q
3M True Definition Scanners use open and trusted connections. what are those?
A
open connections:
- send files directly to your lab
- export files and send to any open CAD/CAM system
- provides options for clean aligners and night guards
trusted connections:
- in-office chairside mills
- digital implant workflows
- orthodontic appliances
- access to digitally produced SLA working models
8
Q
what are the 6 steps for using in-office CAD/CAM?
A
- prepare tooth (and soft tissue) - dentist
- scan - dentist
- design - assistant
- mill - assistant
- polish - stain & glaze - assistant
- seat - dentist
9
Q
what are the training requirements for intra-oral scanning in-office?
A
- initial scanning and “hole filling”
- initial design if available (margin marking)
- lab script completion
- file transfer to laboratory
10
Q
describe the 4 initial requirements of desktop scanning in-office
A
- workstation dedicated to software (desktop or laptop)
- WiFi or LAN network - shielded cable to send files
- proper network specs to maintain speed of file transfer and storage of files
- steady counter/cabinet to hold weight of scanner
11
Q
describe infection control involved in in-office scanning/milling
A
disinfection of wands and keyboards
- Plan Scan-Smart Tips, autoclaveable covers
- ITero and Element: disposable covers
- CS 3500&3600: autoclavable covers
- Straumann Cares/DWIOS: disinfection with wipe
- Tru Def - reportedly immersable in disinfectant
- CEREC - dry heat or disinfection with wipe
12
Q
describe the initial requirements (8) for in-office milling
A
- workstation dedicated to software (desktop or laptop)
- WiFi or LAN network - shielded cable to send files
- proper network and memory to maintain speed of file transfer and storage of files
- steady counter/cabinet to hold weight of mill and footprint
- compressed air connection
- water connection
- distilled water
- lubricant specific to mill
13
Q
what are the use and maintenance requirements for in-office milling?
A
- software updates applied
- bur life and changes
- chuck maintenance
- filter changes for compressor
- cleaning splindle and unit
- lubricant specific to mill
14
Q
what are the training requirements for in-office milling?
A
- operation and maintenance of mill and furnace
- file acquisition and initial design (margin marking)
- restoration design
- material selection and milling
- firing, staining and glazing
15
Q
describe maintaining and troubleshooting if something doesn’t scan or mill as expected
A
- help lines
- dial-in support
- reviewing maintenance
- network issues
16
Q
which milling systems can use resin ceramic?
A
CEREC and PlanMill
17
Q
which milling systems can use feldspathic porcelain?
A
CEREC will, PlanMill will not
18
Q
which milling systems can use leucite-reinforced?
A
CEREC and PlanMill
19
Q
which milling systems can use lithium disilicate?
A
CEREC and PlanMill
20
Q
describe the lab workflow for CAD/CAM
A
- dental office - impression, model, or digital scan
- lab - pour model or scan impression, scan model, or import scan to design software
- CAD (design center or lab) - design restoration
- CAM (milling center or lab) - no model; mill restoration; sinter if necessary, finish and glaze. OR print model or wax pattern for investing, pressing or layering PFM or all-ceramic restorations; printed models are also used for orthodontic and prosthodontic appliances
21
Q
what is an SLA die?
A
- fabricated using SLA (3-D) printing
22
Q
what are some examples of chairside oral scanners?
A
- Lava Chairside Oral Scanner C.O.S. (3M)
- iTero Imaging System (Align Technology, Inc.)
23
Q
what equipment is needed in a milling center?
A
- scanners, design software, milling machines, and sintering ovens
- proprietary and open architecture
- 3-D printing - orthodontic and crown and bridge models
24
Q
T or F:
all shading must be done using shading liquids
A
false:
new ceramics are pre-shaded and layered
25
what is sintering?
* an oven used to allow zirconia to pass through certain phases
* monoclinic to tetragonal, stopping short of cubic
26
describe Lava C.O.S. vs Elastomeric Impressions with respect to perfect, high, and light occlusion
COS
* perfect - 74%
* high - 18%
* light - 8%
Elastomeric Impressions
* perfect - 48%
* high - 46%
* light 6%
overall, Lava C.O.S. provides better results
\*perfect - dentist did not need to use a bur to correct the occlusion
\*high - dentist did need to use a bur to correct occlusion
\*light - no contact; this is bad
27
describe Lava C.O.S. vs. Elastomeric Impressions with respect to mesial contacts
C.O.S.
* perfect - 62%
* tight - 38%
Elastomeric Impressions
* perfect - 43%
* tight - 57%
Lava C.O.S. - better results
28
describe Lava C.O.S. vs. Elastomeric Impressions with respect to fit
C.O.S.
* perfect - 92%
* loose - 8%
Elastomeric Impression
* perfect - 70%
* loose - 30%
Lava C.O.S. - better results
29
describe Lava C.O.S. vs. Elastomeric Impressions with respect to clinically acceptable cases
C.O.S.
* Yes - 95%
* No - 5%
Elastomeric Impression
* Yes - 89%
* No - 11%
Lava C.O.S. - better results
30
describe Lava C.O.S. vs. Elastomeric Impressions with respect to patient preference
* COS - 63%
* elastomeric impression - 8%
* no preference - 29%
31
describe factors in selection of CAD/CAM ceramics
* strength - 120-1200 MPa
* esthetics - anterior vs. posterior
* patient factors
32
what are silica-based CAD/CAM ceramics?
* feldspathic porcelain (CEREC blocs) - not very strong; can't be used for posterior restorations
* leucite-reinforced procelain (IPS Empress CAD)
* lithium disilicate ceramics (IPS e.max CAD)
33
describe flexural strength of silica-based ceramics
* feldspathic porcelain - 100-120Mpa
* leucite-reinforced porcelain - 120-140MPa
* lithium disilicate ceramic - 375MPa
\*gold is around 400MPa
34
describe non-silica based CAD/CAM ceramics
* zirconia (BruxZir Solid Zirconia, BruxZir Anterior, Lava Crowns and Bridges, Lava Plus, NexxZr)
* flexural strength - 500-1500MPa
* veneered core and framework and full-contour restorations
35
what is zirconia?
yttrium-stabilized tetragonal zirconia (Y-TZP)
* \>90% zirconium oxide (ZrO2)
* stabilized with 3.0-5.4% Y2O3, HfO2, Al2O3
* small grains with no glassy phase
* no silica - special primer for bonding
36
what are the benefits of CAD/CAM zirconia ceramics?
* esthetics - excellent
* strength - very high
* fit - excellent
* metal-free
* clinical track record
37
describe the dental advisors clinical track record of zirconia ceramics
* 10-yr Lava recall
* 4-yr BruxZir recall
* 1-yr NexxZr recall
* 1-yr BruxZir anterior recall
38
describe the dental advisors Lava recall at 10-yrs
* over 1300 lava restoration placed since 2003
* 1008 restorations recalled
* molar crowns, pre-molar crowns, anteriors, bridges, and implant abutments
resistance to fracture and chipping:
* fracture rate - 6% - required replacement; molar \> premolar
* chipping rate - 4.7% (roughly same as PFM)
* no fracture/chipping - 89%
39
what are some common reasons for Lava failures?
* undersupported
* underfired
40
describe the recall of BruxZir solid zirconia crowns and bridges at 4-yrs
* 913 restorations recalled at 4-yrs
* single crowns (77%), bridges (16%), and implant crowns (7%)
* most restorations had no chipping or fracture; one crown and two implant crowns failed
* esthetics - excellent - great for patients who want B1 shade
* five restorations exhibited slight marginal discoloration
* minimal wear on restorations and on opposing dentition
* 39 of 913 (2.8%) crowns debonded and were recemented
41
describe the recall of NexxZr T full-contour restoraitons at 1-yr
* 179 NexxZr T full-contour restorations recalled
* 4% of restorations required minor occlusal adjustment at placement
* single crowns (88%), bridges (11%), and implant crowns (1%)
* one premolar crown exhibited chipping; no restorations required replacement
* esthetics - excellent
* excellent resistance to marginal discolorations with self-adhesive and adhesive resin cements
* no wear observed on restorations or on opposing dentition
42
describe the translucency parameters of zirconia, lithium disilicate, and resin ceramic
* zirconia - 7.1-7.8
* lithium disilicate - 13.8-15.8
* resin ceramic - 14.9-17.7
* higher numbers = more translucent
43
describe surface roughness of zirconia, lithium disilicate, and resin ceramic
* zirconia - 0.1-0.15um
* lithium disilicate - 0.28-0.37um
* resin ceramic - 0.34-0.46um
44
what are milled resin ceramics?
* laboratory composite filled with zirconia
* has higher translucency but lower flexural strength
* CeraSmart (GC America)
* Enamic (Vident-VITA)
* Lava Ultimate (3M)
