Chapter 9 Flashcards
Ceramics are used for
Crowns
Fixed bridges
Inlays- occlusal surface
Onlays- 2 or more cusps
veneers
Type of material depends on
the part of the mouth
Stresses
Extent of damage
Esthetic requirement of the patient
The general term ceramics
describe porcelain and a variety if materials similar in appearance, but vary in composition, mode of fabrication, and physical and mechanical properties
Two categories of ceramics
- Glass based
- silica as main component
- More esthetic than the non-glass based
- ex. Feldspathic, leucite-reinforces, and lithium disilicate
- Non-glass based
-Crystalline in nature
- Strongest but dull- ex. Alumina and zirconia
Advantage of all-ceramic restorations
Esthetics, there is no metal substructure to hide
Porcelain
describes a glass-like tooth-colored dental material
- Used more on anteriors, very esthetic
- Porcelain veneers and low stress areas
becomes more fracture resistant ones bonded to a surface
Alumina porcelain
double the fracture resistance
Zirconia
-STRONGEST
opaque and lacks the vitality of natural tooth structure, so it is not very esthetic, but it is very strong
Lithium disilicate
Stronger ceramic
- Used in anterior and posterior
- very esthetic, because of high translucency
- popular for veneers and crowns
Flexural strength is important because
cermaics and stiff and brittle
Ceramics act as _____
Insulators, they don’t conduct heat readily
_____ are the most opaque
non-glass
Biocompatibility
Ceramics are the most biocompatible restorative material
Processing Techniques types
4 types
1. Sintering
- Occurs earn porcelain particles are melted and fused to metal
2. Slip-casting
3. Heat pressing
4. Computer-aided machining
Benefits of CAD/CAM
No cord packing or impression material needed
No die needs to be poured and no temporary crown is necessary
Lithium dislocate and zirconium are much ___ than porcelain
Stronger
ceramics are strong enough to be used in the posterior, besides on
bruxers
Leucite-reinforced ceramics ( empress)
estetic
Work well for inlays, onlays, thicker veneers
not strong enough for posterior crowns
Lithium disilicate EMAX
2x strength as Empress
enough translucency for anterior
used for any restoration
Problem with alumina and zirconia
Strong but opaque so not esteem for anterior teeth
Alumina- good for inlays/onlways hods the discoloration form RCT
Zirconia- alternative to PFM crowns
Veneers
Thin layer of ceramic or composite resin material that is bonded to the fronts of teeth to improve their appearance.
- most common used materials are direct composites or indirect ceramics
Best material for veneers
Ceramic
- more durable, surface doesn’t discolor, more wear resistant and stronger
When the natural tooth structure is___ it makes to challenging to place veneers
Dark
Tooth is etched with ___ acid prior to cementing veneers
hydrofluoric
