Exam 2 Flashcards
Name the types of restoration to consider when selecting a digital impression system
Silica based ceramic Zirconia Resin ceramic Metal Provisional Wax pattern
What is the range of cost for a digital impression system?
10,000 - 125,000
What are some other things to consider when selecting a digital impression system?
In-office milling or milling center
Powder required?
Ortho and implant integration available?
Special features
Name four in -office scanning and in-office milling systems
CEREC (dentsply/sironia)
Apollo DI
Blue cam
Omnicam
Approximately what percent of dentists own a fully scanning system with an in office mill?
25%
What percent of dentists do not own any sort of scanning or milling system?
65%
Name the six steps of in-office CAD/CAM. Identify which parts are typically responsible of the dentist and which parts are responsible of the assistant.
Prepare tooth (and soft tissue) - dentist
Scan - dentist Design - assistant Mill - assistant Polish (stain and glaze) - assistant Seat - dentist
Name the four 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
Name the four desktop scanning in-office initial requirements
Workstation dedicated to software (desktop or laptop)
WiFi or LAN network - shield capable to send files
Proper network specs to maintain speed of file transfer and storage of files
Steady counter/cabinet to hold weight of scanner
In regards to infection control, what products make disinfection of wands and keyboards effective?(6)
Plan scan-smart tips: autoclavable covers
ITero and Element: disposable covers ($2.8 each)
CS 3500: autoclavable covers
Straumann cares/DWIOS: Disinfection with wipes
Tru Def-reportedly immersable in disinfectant
CEREC-Dry Heat or disinfection with wipe
What are the best two mills?
PlanMill 40 (planmeca)
CEREC MCXL (DENTSPLY/sirona)
Name two other in-office mills that are available, but are limited in the material that they can mill
TS-150 (glidewell)
Carestream CS3000
Name the 8 initial requirements for having an in-office mill
Desktop/Laptop WiFi or LAN networks Proper network/memory Counter to bare weight of mill Compressed air connection Water connection Distilled water Lubricant specific to mill
Name the 6 use and maintenance requirements for an in-office mill
Software updates applied Bur life and changes Chuck maintenance Filter changes for compressor Cleaning spindle and unit Lubricant specific to mill
Name the 5 training requirements for an in-office mill
Operation and maintenance of mill and furnace
File acquisition and initial design (margin marking)
Restoration design
Material selection and milling
Firing, staining, and glazing
What are four things you should do when maintain and troubleshooting a problem with a mill when something doesn’t scan or mill as expected?
Call help lines
Dial-in support
Review maintenance
Check network issues
What four materials can the CEREC mill?
Resin ceramic
Feldspathic porcelain
Leucite-reinforced
Lithium disilicate
True or false… zirconia can be milled by CEREC and Planmill
False. Neither can mill zirconia
Planmill can mill every material CEREC can besides what material?
Feldspathic porcelain
What are the three types of scanning you can perform in a dental office?
Impression
Model
Digital scan (intraoral)
If you send an impression to a lab, what things will the lab do?
Pour model, then scan model
Or….
Scan impression
Name a SLA (3d) printer used in a dental office
ProJet 1200 (whip mix)
Name two chair side oral scanners - digital transfer to milling/printing center
Lava chair side oral scanner
iTero Imaging system (align technology inc.)
What does CAD/CAM stand for?
Computer-aided design/computer-aided manufacturing
What is CNC?
Computer numerical control
What two CAD/CAM systems dont involve an in-office mill and instead require a laboratory?
Itero
Lava chairside oral scanner
What two CAD/CAM systems involve an in-office mill (with still an option to mill by dental technicians)?
CERAC AC
E4D Dentist
True or false… new ceramics are now preshaded and layered
True
What type of zirconia is formed in the sintering process?
Monoclinic or tetragonal. …stopping short of cubic
What types of material can be milled with CAD/CAM systems?
Composites
Feldspathic porcelain
Leucite reinforced ceramic
Lithium disilicate ceramic
Zirconia
Why is it necessary to dust the preparation with titanium dioxide powders for some CAD/CAM systems?
They use video or static imaging methods that provide the best images when the preparation is void of specular reflection. The powder provides surfaces that are uniform in color and reflectance
Is the long term survival rate of CAD/CAM fabricated restorations similar to restorations fabricated by traditional methods?
Yes. 5 year survival rates of 92-95%
Are lava cos better at occlusion points than elastomeric impressions? What about mesial contacts, fit, clinical acceptance, and patient preference?
Yes to all
What are the three factors in selecting CAD/CAM ceramics? What is the strength range for materials Available for cadcam?
Strength (120-1200)
Esthetics
Patient factors
List the following from lowest to greatest translucency
Lithium disilicate
Resin ceramic
Zirconia
Zirconia
Lithium disilicate
Resin ceramic
What are the two objectives of cementation or luting?
Help maintain restoration in place
Maintain integrity of remaining tooth structure
Retention of the restoration is achieved by…
Friction Adhesive joint Cement Restoration Both mechanisms
An effective interfacial seal depends on the ability of the cement to _____ between the tooth and the restoration and resist the ______ short term and long term
Fill the irregularities
Oral environment
Strong bone between the outing and dental substrates is important because _____
It can prevent infiltration of bacteria and fluids that can cause caries and sensitivity to the patient
What are the two classifications of luting agents according to the length of time that they are expected to stay in function?
Provisional: low strength and easy handling, no irritate pulp.
Definitive: remain in function for the longest time possible.
Give 3 example of a provisional luting agent
Zinc oxide
Non-eugenol cements
Calcium hydroxide pastes
What are the two types of Luting agents according to setting? Give examples
Acid based reaction: GI, RMG, zinc-oxide eugenol, zinc polycarboxylate, and zinc phosphate
Polymerization: resin cement, composers, and self-adhesive cements
Name four materials that can have a chemical interaction with hydroxyapatite
Zinc polycarboxylate
GI
RMG
Self-adhesive resin cements
About what percentage of all restorations placed in general dental practice are done to replace defective or failed restoration?
50%
What are the three reasons that restorations are replaced?
Clinician factors
Material properties
Patient factors
What is the dentin called that surrounds the dentin tubule?
Peritubular dentin
Describe the composition of dentin
50% mineralized apatite crystals
20% water
30% organic matrix (collagen)
True or false… the diameter and number of dentin tubules increase near the enamel
False.. it increases near the pulp
Name three characteristics of sclerotic and caries-affected dentin
Hypermineralized
Tubules occluded with CaPO4 crystals
Acid-resistant
What may happen to the collagen fibers in over-dried dentin?
They may collapse
What may occur to dentin due to the overwet phenomenon?
Water forms a “blister” over the dentin and prevents proper interaction with the primer (acid)
How thick is the smear layer of dentin?
0.5 - 2.0 micrometers thick
What is the smear layer composed of? Can it be directly removed by rinsing?
Bacteria
Saliva
Blood cells
Denatured collagen
No, it cannot be removed by rinsing
Define hybrid
“A thing made by combining two different elements; a mixture”
Describe the hybrid layer found in dental hard tissues
Due to demineralization of the surface and subsurface, followed by the infiltration of monomers and subsequent polymerization
Describe the composition of a primer used in dentin adhesion?
Hydrophilic monomer (HEMA)
Water-soluble solvent (water, acetone, ethanol)
(Note that hema becomes hydrophobic when it dries to allow bonding with the adhesive
Describe the composition of an adhesive used in dentin adhesion
Unfilled or lightly filled resin (Bis-GMA)
Describe the fourth generation adhesive strategy
Uses enchant to remove smear layer
Uses primer
Uses adhesive
Describe the fifth generation of adhesion
Uses etchant to remove smear layer
Uses a combined primer and adhesive resin
Describe the 6th generation of adhesion?
Uses a self-etching primer that dissolves the smear layer
Uses a separate adhesive
Which is more predictable, fourth or fifth generation? Why?
Fourth
The fifth generation is more susceptible to differences in wetness
What are some features of self-etching adhesives?
Significant difference in technique User friendly (no more etching)
Acidic monomer dissolves smear layer and primes dentin simultaneously
One step or two step systems
True or false… self-etching adhesives result in higher bond strengths in deep dentin in comparison to 5th and fourth generation adhesives
True
Does self-etching adhesives bond best to cut enamel or uncut enamel?
Cut enamel
