METAL-CERAMIC RESTORATION (cabogs) Flashcards
Substructure Coated with Ceramic Veneer
Egyptian
Vitrification,
Impermeability
Translucency,
Hardness,
Chinese
Basic Components Kaolin and Feldspar
European 1800’s
Use In Dentistry
Pierre Fauchard
is an aluminosilicate mineral derived from the decomposition of feldspar from igneous rock.
Kaolin
The term kaolin derives from the name of the deposit in ___ where the mineral was first mined - Kao-ling.
China
____ is an important source of alumina in the
glassmaking and ceramics industries. In ceramics, it acts as
a flux and provides the vitreous luster of chinaware and
ceramic tiles.
Feldspar
is used in glazes and enamels and is an
important mineral filler in paints, plastics, sealants, and
adhesives.
Feldspar
BASIC COMPONENTS OF PORCELAIN
• Ball clays
• Kaolin
• Feldspar
The formation of _____ relies on the weathering or
hydrothermal alteration of aluminosilicates. Thus,_____
is formed in soils and sedimentary materials that contain
aluminosilicates.
kaolinite
In a variety of manufacturing contexts, such as ceramics,
porcelain, adhesive, concrete additives, and paper filler.
KAOLIN
It is also used in medicine for its anti-inflammatory,
antibacterial, antiviral, and antidiarrheal properties.
KAOLIN
T/F
PROPERTIES OF KAOLIN
Kaolinite is a white, powdery solid that does not absorb
T
T/F
PROPERTIES OF KAOLIN
Its melting point is between ____ and ___ degrees
Celsius
740, 1785
T/F
PROPERTIES OF KAOLIN
Its density is ___ grams per cubic centimeter.
2.65
T/F
PROPERTIES OF KAOLIN
In ceramics manufacturing, kaolin is used to modify the
properties of a ceramic body with the ball clay (plastic clay),
primarily to control and adjust the casting rate of the ceramic
body.
T
Metal substructure supporting a ceramic veneer that is
mechanically and chemically bonded.
METAL-CERAMIC RESTORATION
Achieved through firing.
METAL-CERAMIC RESTORATION
T/F
METAL PREPARATION
Sharp angles should be
avoided
Internal stress in the final
restoration
T
T/F
METAL PREPARATION
Convex surfaces and rounded
contours should be created To avoid development of stress
concentrations
T
T/F
METAL PREPARATION
Smooth surface, Facilitates wetting of the
framework by the porcelain
slurry
T
T/F
METAL PREPARATION
80° angle should be smooth
and defined for metal-ceramic
junction For easier finishing
F
(90° angle should be smooth
and defined for metal-ceramic
junction)
T/F
METAL PREPARATION
The metal framework must be
thick enough to prevent
distortion
T
METAL PREPARATION STEPS
• Shaping
• Investment Removal
• Oxide Removal
• Metal Finishing
• Cleaning
• Oxidizing
METAL PREPARATION
Ultrasonic cleaning to eliminate all investment material.
1
METAL PREPARATION
Oxide layer formed on the metal surface must be partially
removed
2
METAL PREPARATION
Successful bond depends on controlled thickness of the
metal-oxide layer.
3
METAL PREPARATION
Finishing the surface in one direction with light pressure
avoids trapping debris between folds of the metal using
ceramic-bound stones to prevent contamination
4
METAL PREPARATION
Should be airborne-particle abraded with aluminum oxide to
create a satin finish on the veneering surface
5
METAL PREPARATION
Should conform to all specified minimum dimensions to
avoid distortion during firing
6
METAL PREPARATION
The metal-ceramic interface should be configured at right-
angle.
7
METAL PREPARATION
Small particles, grinding debris, oil, and finger grease must
be removed because they interfere with the wetting process
(ultrasonic cleaning or by steam cleaning)
8
METAL PREPARATION
Controlled oxide layer must be created on the metal surface
to establish chemical bond between metal and porcelain
9
METAL PREPARATION
The first porcelain application can be performed as soon as
the casting has cooled off to room temperature after it is
removed from the furnace
10
ALLOY COMPOSITION
HIGH-NOBLE
SEMI-PRECIOUS OR NOBLE
NON-PRECIOUS OR BASE METAL
60% noble metals, including a combination of
gold, platinum, or palladium with a minimum of
40% gold content.
A. HIGH-NOBLE
B. SEMI-PRECIOUS OR NOBLE
C. NON-PRECIOUS OR BASE METAL
A. HIGH-NOBLE
25% or more gold or other noble metals
supplemented with other metal Elements.
A. HIGH-NOBLE
B. SEMI-PRECIOUS OR NOBLE
C. NON-PRECIOUS OR BASE METAL
B
Less than 25% noble metal content combined
with chromium beryllium, nickel, and cobalt.
A. HIGH-NOBLE
B. SEMI-PRECIOUS OR NOBLE
C. NON-PRECIOUS OR BASE METAL
C
Additional elements may include tungsten,
manganese, iron, silicon, carbon, and
molybdenum.
A. HIGH-NOBLE
B. SEMI-PRECIOUS OR NOBLE
C. NON-PRECIOUS OR BASE METAL
C
Produced from blend of
o Quartz (SiO₂)
o Feldspar (potassium aluminum silicate orthoclase, sodium aluminum silicate albite)
o Other oxides
DENTAL PORCELAIN
• Heated to high temperature.
• Frit is ball-milled to desired particles
DENTAL PORCELAIN
Formulations designed for metal ceramics consist of mixture
of two frits; a low fusing glass frit and a high expansion frit
DENTAL PORCELAIN
Crystalline leucite with tetragonal symmetry
DENTAL PORCELAIN
Also contains alumina (Al₂O₂) which acts as intermediate oxide to increase the viscosity and hardness of the glass
FELDSPAR
Results to good resistance to slump and pyroplastic flow
FELDSPAR
Necessary for obtaining the desired configuration of the
restoration.
FELDSPAR
Opaque
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
A
Masks the dark metal oxide
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
A
Primary source of color
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
A
Body/dentin porcelain
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
B
Slightly translucent
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
B
Enamel porcelain
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
C
More translucent
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
C
Contains little pigmentation
A. FIRST LAYER
B. SECOND LAYER
C. SUPERFICIAL LAYER
C
CERAMIC LAYERS
Noble metal alloy = ___mm
0.3mm
CERAMIC LAYERS
Base metal alloy = ___mm
0.2
must wet the surface easily, 1° source of
color, 0.1mm
Opaque Porcelain
built to anatomic contour; incisal, body,
gingival
Body and Incisal
Porcelains
intrinsic staining by incorporating colored
pigments
Internal
Characterization
size, line angles, creating illusion on how
it appears
Contouring
to create shiny surface, occlusal contact
is altered
Glazing and
Surface
Characterization
surface stains
External
Characterization
is the primary layer porcelain for improving the
adhesive strength and controlling the color of the oxidized surface of
the alloy.
Super Opaque
