Digital Impressions and CAD/CAM Restorations Flashcards
what are 2 in vitro studies conducted by the dental advisor?
- biomaterials
- microbiology
what are 3 clinical marketing studies conducted by the dental advisor?
- restorative materials - placement and long-term
- infection control products
- equipment
describe 4 of apex dental milling’s products
- full-contour zirconia - anterior and posterior
- zirconia frameworks and copings
- pressed lithium disilicate
- printed orthodontic and C&B models
what are the 6 main factors that need to be considered in selection of digital impression systems
- 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
what is CEREC?
- in-office milling system owned by DENTSPLY
- 3 types: APOLLO DI, BLUECAM, OMNICAM
what are the major in-office milling systems?
- 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)
3M True Definition Scanners use open and trusted connections. what are those?
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
what are the 6 steps for using in-office CAD/CAM?
- prepare tooth (and soft tissue) - dentist
- scan - dentist
- design - assistant
- mill - assistant
- polish - stain & glaze - assistant
- seat - dentist
what are the training requirements for intra-oral scanning in-office?
- initial scanning and “hole filling”
- initial design if available (margin marking)
- lab script completion
- file transfer to laboratory
describe the 4 initial requirements of desktop scanning in-office
- 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
describe infection control involved in in-office scanning/milling
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
describe the initial requirements (8) for in-office milling
- 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
what are the use and maintenance requirements for in-office milling?
- software updates applied
- bur life and changes
- chuck maintenance
- filter changes for compressor
- cleaning splindle and unit
- lubricant specific to mill
what are the training requirements for in-office milling?
- operation and maintenance of mill and furnace
- file acquisition and initial design (margin marking)
- restoration design
- material selection and milling
- firing, staining and glazing
describe maintaining and troubleshooting if something doesn’t scan or mill as expected
- help lines
- dial-in support
- reviewing maintenance
- network issues
which milling systems can use resin ceramic?
CEREC and PlanMill
which milling systems can use feldspathic porcelain?
CEREC will, PlanMill will not
which milling systems can use leucite-reinforced?
CEREC and PlanMill
which milling systems can use lithium disilicate?
CEREC and PlanMill
describe the lab workflow for CAD/CAM
- 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
what is an SLA die?
- fabricated using SLA (3-D) printing
what are some examples of chairside oral scanners?
- Lava Chairside Oral Scanner C.O.S. (3M)
- iTero Imaging System (Align Technology, Inc.)
what equipment is needed in a milling center?
- scanners, design software, milling machines, and sintering ovens
- proprietary and open architecture
- 3-D printing - orthodontic and crown and bridge models
T or F:
all shading must be done using shading liquids
false:
new ceramics are pre-shaded and layered
what is sintering?
- an oven used to allow zirconia to pass through certain phases
- monoclinic to tetragonal, stopping short of cubic
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
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
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
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
describe Lava C.O.S. vs. Elastomeric Impressions with respect to patient preference
- COS - 63%
- elastomeric impression - 8%
- no preference - 29%
describe factors in selection of CAD/CAM ceramics
- strength - 120-1200 MPa
- esthetics - anterior vs. posterior
- patient factors
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)
describe flexural strength of silica-based ceramics
- feldspathic porcelain - 100-120Mpa
- leucite-reinforced porcelain - 120-140MPa
- lithium disilicate ceramic - 375MPa
*gold is around 400MPa
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
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
what are the benefits of CAD/CAM zirconia ceramics?
- esthetics - excellent
- strength - very high
- fit - excellent
- metal-free
- clinical track record
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
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%
what are some common reasons for Lava failures?
- undersupported
- underfired
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
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
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
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
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)
