CERAMIC VENEERED
CROWN
Dr/Eslam Omar Sayed
Lecturer Of Fixed Prosthodontics
Faculty Of Dentistry
Asyut University
B.D.S. Minia University ,2011
M.D.S. Minia University ,2018
PHD , Minia University 2023
Intended learning objectives (ILOs)
• Definition
• Advantage and disadvantage
• Indications and contraindications
• Tooth preparation
• Methods of Bonding of Veneered material
TYPES OF FIXED PROSTHODONTIC
RESTORATION
Intracoronal
Extracoronal
Restoration
Intraradicular
Extra
coronal
Intra
coronal
Full
coverage
Inlay
Intra
radicular
Endocrown
Partial
coverage
Onlay
‫ب‬
FULL COVERAGE CROWN
Full veneer metal crown
Jacket crown
Veneered crown
Full Veneered Crown
Definition of Veneered crown
Metal-ceramic crowns consist of a complete-coverage metal crown (or
substructure) that is veneered with a layer of fused porcelain to mimic the
appearance of a natural tooth
It is a full coverage cast metal crown which has a labial
esthetic facing either porcelain or acrylic resin
Veneered
If it covers the labial,
incisal and part of the
proximal surface
Full
veneered
If it cover all
surfaces(labial
,lingual,proximal,icisal)
Objective of Veneered Crown
Full metal
coverage
strength
Veneering
with acryl or
porcelain
Aesthetic
Indication of veneered
crown
On teeth that require complete coverage and for which esthetic is
demanded
Long span fixed partial denture
Metal substructure can be modified to incorporate occlusal and cingulum rests and
milled proximal and reciprocal guide planes which can not be achieved in all ceramic
crown
extensive tooth destruction-as a result of caries ,trauma or existing previous
restorations
need for superior retention and strength; an endodontically treated tooth in
conjunction with a suitable supporting structure (a post-and-core)
INDICATION OF VENEERED CROWN
As A Crown And A Bridge Retainer
Cingulum And Occlusal Rest
Contraindication of
veneered crown
The presence of active caries or
untreated periodontal disease
Young patients with large pulp chambers
Should not be considered when a more conservative retainer is
feasible unless maximum retention and resistance form are
needed ,as for long span FPD
Short crowns
Where esthetics is of prime importance
Contraindications of veneered crown
SHORT CLINICAL CROWNS
LARGE PULP IN YOUNG
PATIENTS
Advantage of veneered
crown
Combines to some degree the strength of cast metal
with the esthetics of an all-ceramic crown.
Ease of preparation than partial coverage
Because of including axial walls in preparation this
provides adequate resistance and retention form
complete-coverage aspect of the restoration
permits easy correction of axial form
Disadvantage of
veneered crown
Significant tooth reduction to provide sufficient space for materials
For superior esthetics facial surface placed sub gingivally
increasing potential for periodontal disease
Inferior esthetics when compared to all ceramic restorations
and full veneered restorations
Difficulty of accurate shade selection
Chipping and fracture of porcelain may occur
DISADVANTAGE OF VENEERED CROWN
METAL DISPLAY
PORCELAIN FRACTURE
Tooth preparation
Criteria of the Preparation
Lingual surface:
Chamfer finish line (0.3- 0.5 mm)
Buccal surface :
Shoulder finish line (1-1.5mm).
Or heavy chamfer finish line (0.8- 1mm)
Incisal surface: the amount of reduction (2mm)
The meeting of the 2 finish lines:
form a half groove or wing on the proximal surfaces.
• Since , the crown is a combination of metal and
ceramic, the tooth preparation is also
combination of deep reduction facially and
shallower reduction lingually.
• The wing on each proximal surface is where the
deep reduction ends and the shallower proximal
reduction begins
• To ensure esthetics the shoulder finish
line must extend at least 1 mm lingual to
proximal contact area.
• Lingual reduction of 1 mm is needed in
anterior teeth to provide clearance if
contact is on metal while 1.5 mm is
needed if the contact is on porcelain.
Lingual reduction:
if contact is on
metal 1 mm is
needed
for
clearance
Lingual reduction:
if contact is on
porcelain 1.5 mm
is
needed
for
clearance
Steps of preparation
INSTRUMENTS
Round–ended, tapered diamond (for chamfer
or heavy chamfer preparation).
Football –or- wheel –shaped diamond (For
lingual reduction of anterior teeth).
Flat –ended, tapered diamond (for shoulder
preparation).
Finishing stones.
Explorer and periodontal probe
Anterior Veneered
Preparation
STEPS OF THE PREPARATION
An index is made before the preparation is begun, to have possible positive check on
reduction. If the contours are correct, the index can be made intraorally, if not, the index
should be made from a preoperative wax-up on the diagnostic cast
STEPS OF THE PREPARATION
Incisal reduction:
Instrument :either wheel stone
or tapered with flat end
- Direction: in mesio-distal direction.
inclined 45° with the long axis of the tooth.
- Amount of cutting: is 1.5-2mm WHY???
STEPS OF THE PREPARATION
1
2
3
4
STEPS OF THE PREPARATION
Labial reduction:
Instrument : Tapered with flat end
- Finish line : Shoulder finish line 1-1.5mm .
Or
Tapered stone with round end
- Finish line : Heavy chamfer finish line 0.8-1mm.
Direction: in mesio-distal direction.
2 PLANES : gingival 1/3 ---- // to the long axis
incisal 2/3 ---- with 45°to the long axis.
-Amount of cutting: 1- 1.5 mm
STEPS OF THE PREPARATION
2
11
33
4
Labial surface should be prepared in TWO distinct planes.
B) Labial surface prepared in one plane // to path of insertion, result in insufficient
space for porcelain in incisal 1/3 of labial surface
C) Labial surface prepared in one plane with more than sufficient space
, will endanger the pulp & produced over tapered preparation
Labial reduction ends around the labio-proximal line angle
to 1mm lingual to the proximal contact
PROXIMAL REDUCTION
Proximal reduction
2-6° converging angels
Lingual Reduction :
Instrument :
lingual fossa concavity is prepared with football or wheel stone,
cingulum reduction with Tapered with rounded end
Finish line : Chamfer finish line .
Direction:
cingulum reduction should be parallel to the gingival 1/3 of the
labial surface.
Wing or 1/2 Groove:
Extending : gingivo-axially,
Location :1mm palatal to the
contact point.
Finishing of the Preparation
All line and point angles should be rounded.
The labial half should end with a shoulder F.L. 1 mm in thickness
The palatal half has a chamfer F.L. 0.3— 0.5 mm in thickness.
Finishing of the Preparation
A smooth transition is necessary.
The meeting of the two F.L. will make
a step or 1/2 a groove along the incisogingival length of the preparation.
Proximal walls should have a 6° taper
Posterior Veneered Preparation
similar to anterior teeth reduction with:
Functional cusp bevel
Occlusal clearance:
( 1-1.5 mm reduction if occlusion is to be restored in
metal)
( 1.5-2 mm if occlusion is to be restored in metal +
ceramic )
Veneered preparation for posterior teeth
As anterior + a functional cusp bevel
Finish Line Designs on Facial Surface
90° Shoulder,
Heavy champer
Beveled Shoulder (sloped )120 °
Wingless preparation
No distinct transition from the
shoulder to chamfer is seen.
Indications
Thin Teeth
Proximal Caries
Proximal Restoration
Precision Attachment
Wing preparation
Wings provide :
Resistance to rotation & torque
Conserve tooth structure, if NOT
located lingual to contact point
restoration will lack translucency
WING EXTENSION
On the mesial the
preparation
extends
farther than the distal
side . WHY?????
Occlusal Extensions Of Veneered Material
Facial Extensions of Veneered Material
Collar or collarless?
Metal Collar
Depends on :
Adaptation & esthetic needed
Porcelain Labial margin
Porcelain Labial margin ( Metal collarless)
Metal coping is terminated 1mm shorter than finish line
Shoulder porcelain (Aluminous porcelain) fuses at high temp.(30-80°C)higher than
body& enamel porcelain WHY???
•
To allow repeated firings
•
stronger in flexure strength
If metal collar is used, the
finish line must be located
subgingivally
- In case of supragingival
finish line, metal collar is
eliminated
and
shoulder
marginal porcelain is used
Methods of Bonding of
Veneered material to Alloy
Methods of Bonding of Veneered material
to Alloy
I-Metal-Acrylic Resin
Bonding
Intermediary
coupling agent
Mechanical
Undercut
Beads
Wire loops
Silicoating
Electrolytically
II-Metal-Ceramic Bonding
Mechanical
Chemical
Compression
Van der
Waals forces
Mechanical bonding:
By mico-roughness ( air- abrasion)
To :
mechanical interlocking ,
enhance wettability , surface
area for chemical
bonding.
Chemical bonding:
Formation of oxide layer .
Gold alloys, from tin, indium or
gallium
Base metal alloys , from chromium
oxide
Compressive bonding:
Due to the slightly smaller
coefficient of thermal expansion of
porcelain than for the metal alloy (1×
10-6ºC)
Preparation designed for full porcelain
coverage
of
metal.
Compressive
stresses set up in the porcelain on
cooling are balanced by the tensile
stresses developing in the higher
thermal expansion metal.
C–Compression, T–Tension.
Preparation
designed
for
partial
metal coverage. Tensile stresses in
lingual metal are not balanced by
compressive stresses in porcelain
thereby creating high stress at the
porcelain/metal interface.
C–Compression, T–Tension.
Metal extending too
far incisally makes
the
unsupported
porcelain prone to
fracture.
Opposing cusps must never
contact a junction line
between
metal
and
porcelain.
Maxillary posterior metal–ceramic coping with (a) proper metal support and (b)
without proper metal support under facial cusp.
Thank
you