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1. PARTIAL COVERAGE
CROWNS - POSTERIORS
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2. INDIAN DENTAL ACADEMY
Leader in continuing dental education
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3. INTRODUCTION
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4. 
An extracoronal restoration that covers only part
of the clinical crown considered to be a partial
veneer crown. It can also be referred to as a
partial coverage restoration.
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5. DEFINITION

A restoration that restores all but one coronal surface of
a tooth, usually not covering the facial surface.(GPT- 8)

A partial veneer crown is a restoration covering two or
more surfaces of a tooth (Tylman)
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6. TYPES OF PARTIAL COVERAGE
CROWNS

For posterior teeth-1)Three-quarter crown
2)Modified three-quarter crown
3)Seven-eighth crowns
4)proximal half crowns
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7. INDICATIONS FOR PARTIAL VENEER
CROWNS:

Partial veneer crowns are a conservative measure
and are preferable to the complete veneer
restoration.

Intact or minimally restored teeth.

Teeth with crown length that is average or that
exceeds the average.
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8. 
Teeth with normal anatomic crown form, i.e.,
without excessive cervical constriction.
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9. CONTRAINDICATIONS FOR PARTIAL
VENEER CROWNS:



High caries rate.
Teeth with extensive restoration
Deep cervical lesion – difficult to establish finish
line , if area is sensitive complete coverage crown
is indicated.
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10. 
Teeth with short clinical crown – difficult to
achieve resistance and retention form.

Thin teeth – preparation of retention grooves is
difficult.

Poor alignment of teeth in the dental arch.
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11. ADVANTAGES OF PARTIAL VENEER
CROWNS:

Partial veneer crowns have several advantages over
complete crowns:

The tooth reduction is conservative.

The esthetics surpass the complete veneer cast
crown.

Margin accessibility for finishing and cleaning is
improved.
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12. 
Complete seating of the casting is more easily
verified.

Complete seating of the casting during
cementation is enhanced by diminished
hydraulic pressure.

Electric pulp testing can be conveniently
accomplished on the intact enamel surface.
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13. DISADVANTAGES OF PARTIAL VENEER
CROWNS:

The partial veneer crown is not as retentive as a
complete veneer crown.

Skillful preparation is critical to avoid metal
display.

The partial veneer crown preparation is limited to
fairly intact teeth with normally shaped crown
and an average length clinical crowns
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14. Fundamental Principles of Design:
1) To impart strength to the remaining portion of the
tooth crown.
2) To provide maximum resistance and retention
form to the finished restoration.
3) To preserve esthetics by conservation of tooth
structure, thus limiting the display of gold on
buccal and labial surfaces.
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15. ROTARY INSTRUMENTS USED FOR TOOTH
PREPARATIONS








Round end tapered diamond,
Torpedo diamond,
Short needle,
Long needle,
Flame diamond,
Small wheel diamond,
Tapered fissure burs
End cutting bur
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16. Steps for preparation of partial veneer crowns

Outline Form

Lingual reduction


Incisal reduction
Lingual axial reduction
Proximal axial reduction
Proximal box or groove placement

Occlusal or incisal offset placement

Facial bevel

Finishing the preparation.


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17. Maxillary posterior three quarter
crowns
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18. Occlusal reduction

No. 171 or round-end
tapered diamond is used

Depth orientation
grooves are made on the
triangular ridges and the
developmental grooves
1.0mm on the non
functional and 1.5mm on
the functional cusp
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19. 
At the occluso-facial line
angle groove is made
only 0.5mm deep to
minimize the display of
metal.

Tooth structure from
between the grooves is
removed according to
cuspal contours
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20. Functional Cusp Bevel


Should be parallel to
the inward facing
inclines of the cusps of
the opposing tooth, at
depth of 1.5mm
creating 45˚ angle with
the axial wall.
No. 171 bur
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21. Lingual Axial Reduction



Torpedo diamond
creating a definite
chamfer all over.
Over inclination of
the lingual wall
frequently occurs.
Check at all times for
over inclination.
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22. Proximal Reduction


Initially thin needle
diamond is used in
sawing motion to just
break the contact with
the adjacent tooth
Once contact is broken,
torpedo diamond is
used to create a definite
chamfer finish line and
complete the axial and
proximal reduction.
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23. Axial Finishing

Torpedo bur is used to
finish the axial walls
and round of the
margins of the
preparation.
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24. Proximal Groove




Parallel to the incisal two
thirds of the facial surface.
Orientation cut is made using
no.170 bur depth 1.0mm or
less.
Groove is continued apically
to about 0.5mm above the
chamfer finish line.
Grooves on mesial and distal
side are made parallel to each
other.
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25. Proximal Flares


Flame diamond and
flame bur is used to
produce the proximal
flares that is a flat
geometric plane.
When access is good a
medium grit sandpaper
disc may be used.
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26. Occlusal Offset

No. 171 bur used to
create a 1 mm ledge on
the lingual incline of
the facial cusp
connecting the grooves
and assuming an
inverted V shape.
No.957 end cutting bur
is used to define the
margins
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27. Facial bevel

Flame diamond is used
to bevel the occlusofacial line angle
keeping it
perpendicular to path
of insertion. The bevel
should not be more
than 0.5mm wide.
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28. Completed three quarter crown
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29. Features of the Maxillary Posterior Three
Quarter Crown Preparation
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30. 

A common variation of the
three quarter crown
preparation , employed
when caries or previous
restorations are present on
the proximal surfaces, is
one in which boxes are
substituted for grooves.
However boxes are very
destructive of tooth
structure, so their use can
be justified only when
tooth structure has been
destroyed by caries
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31. 

A less destructive
alternative for augmenting
retention and resistance is
a three quarter crown
preparation utilizing two
grooves on each proximal
surface.
There is no significant
difference between
retention afforded by the
four grooves and that
available from two boxes.
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32. Mandibular Posterior Three Quarter
Crown
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33. Occlusal Reduction




No. 171 or torpedo diamond is
used
Depth orientation grooves are
made on the triangular ridges and
the developmental grooves 1.0mm
on the non functional and 1.5mm
on the functional cusp
At the occluso-facial line angle
groove is made only 0.5mm deep
to minimize the display of metal.
Tooth structure from between the
grooves is removed according to
cuspal contours
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34. Thank you
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Leader in continuing dental education
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