IRST Flashcards
What are the types of scans?
Intraoral - digital impressions, opposing, preoperative, soft tissues
= Substitutes the impression
Extraoral (benchtop) - can scan impressions, models, wax up, opposing, preoperative, articulation
What comes after scanning?
Computer aided design
- Chairside
- Laboratory
What is chairside CAD used for?
Mainly used for diagnostic and planning work
Can produce indirect restorations - CEREC system
- Composite
- Feldspathic ceramic
- Hybrid materials
Anything produced chairside will be monolithic (one material)
Good for posterior teeth
Not very good for aesthetic restorations
Laboratory CAD?
For diagnostic and planning Orthodontic - invisalign Indirect restorations Model production Partial denture Complete dentures
Computer aided manufacturing types?
Subtractive (milling)
or
Additive (3D printing, selective laser melting)
Subtractive manufacturing uses?
Ceramics (feldspathic/lithium disilicate/zirconia)
Wax/wax substitutes for lost wax casting (acrylic)
Metals (and partially sintered metals
Polymers (PEEK)
Additive manufacturing uses?
Model materials
Wax/wax substitutes for lost wax casting)
Metals (SLM)
Ceramics and high performance polymers
Lab communication - what to consider? (what you write on a prescription card)
Diagnostic wax up Imp taking - working, opposing, interocclusal record Shade Model types Lab requirements
Production methods for metal restorations? Metal alloys?
Conventional production - Wax pattern and lost wax casting Digital production - Scan - CAD - CAM Metal types I-IV gold alloys, AgPd alloys, NiCr/CoCr
Resin bonded restoration production?
Conventional production - Sintering - refractory model - Wax pattern - pressing Digital production - Scan CADCAM - CAM: Ceramic mill/Wax mill/Print (wax) Materials - feldspathic for sintering or milling, lithium disilicate: milling, pressing (fluorapatite glasses sintered ontop)
Metal ceramic crown production?
Conventional production
- Wax pattern and lsot wax casting
- Sintering of ceramic veneer
Digital production
- CADCAM
- Metal milling- selective laser melting
What to consider with metal ceramic crowns? Types of metals used?
Substructure design
- Exterior surface, contact points, margin material
Metal types
- Bonding alloys
- Hi, medium and low gold alloys
- NiCr, CoCr, Ti alloys
High strength ceramic production?
Conventional production
- Glass infiltrated
Digital production
- Scan CADCAM
- Milling
How can zirconia be produced?
CADCAM/milled
High strength ceramic types?
Substructure: Veneering ceramic added via sintering or pressing
Monolithic: Zirconia available in different translucency
Compare to lithium disilicate
