Posterior partial veneer crowns / dental implant courses by Indian dental academy

Posterior partial veneer
crowns
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Contents -
 Definition
 Classification
 Indication and contraindications
 Advantages and disadvantages
 Armamentarium
 Preparation

Partial veneer crown:A restoration that restores
all but one coronal surface of a tooth usually not
covering the facial surface(GPT-7;1999)

TYPES OF PARTIAL VENEER CROWNS:
For posterior teeth:
 Three quarter
 Modified three quarter
 Seven-eighths
For anterior teeth:
 Three quarter
 Pinledges

INDICATIONS
Posterior teeth that have lost moderate amounts of
tooth structure provided the buccal wall is intact
and well supported by sound tooth structure.
Can be used as retainers for FPDs or when
restoration or alteration of occlusal surface is
needed.
In anterior region they can be used as retainers to
reestablish anterior guidance and to splint teeth.
Particularly suitable for teeth with sufficient bulk
because they can accommodate the necessary
retentive features

CONTRAINDICATIONS:
Teeth with short clinical crowns because retention
might not be adequate.
Contraindicated as retainers for long span bridges.
Rarely suitable for endodontically treated teeth
(esp. anteriors) because insufficient tooth
structure remains for the retentive features.
In dentitions with active caries and / or
periodontal disease.
In poorly aligned teeth.

Advantages:
Tooth structure is spared.
Much of the margin is accessible to the dentist for finishing
and to the patient for cleaning.
Less restoration margin is in proximity to the gingival
crevice lowering the possibility of periodontal irritation.
An open faced partial veneer crown is more easily seated
completely during cementation while a full veneer crown
tends to act like a hydraulic cylinder containing a viscous
fluid.
With some of the margins visible, complete seating of a
partial veneer crown is more easily verified.
If an electric pulp test ever needs to be conducted on the
tooth a portion of enamel is unveneered and accessible.

DISADVANTAGES:
Partial veneer crowns have less retention and
resistance than full coverage crowns.
Preparing a tooth for this kind of treatment is
difficult primarily because only limited
adjustments can be made in the path of
withdrawal.
The placement of grooves, boxes and pinholes
requires dexterity from the operator.
Some metal is displayed in the completed
restoration which may be unacceptable to patients
with high cosmetic expectations

Armamentarium
ROUND END
TAPERERED DIAMOND
1.DEPTH ORIENTATION GROOVES
2.OCCLUSAL REDUCTION
3.FUNCTIONAL CUSP
TORPEDO DIAMOND 1.AXIAL REDUCTION
2. CHAMFER FINISH LINE
SHORT NEEDLE INITIAL INTERPROXIMAL REDUCTION
IN POST. TEETH
LONG NEEDLE INITIAL INTERPROXIMAL REDN. IN
ANT. TEETH

SMALL WHEEL
DIAMOND
LINGUAL REDUCTION IN ANTERIOR
TEETH
TAPERED FISSURE
BUR
1.SEATING GROOVE
2.PROXIMAL GROOVE
3.OCCLUSAL AND INCISAL BEVELS
4.SMOOTHENING AND FINISHING
SMALL DIAMOND
(1/2 DIAMOND)
INITIAL PIN PREPARATION
TWIST DRILL
0.6MM/0.7MM
PIN PREPARATION
TORPEDO BUR AXIAL WALL FINISHING
CHAMFER FINISHING
FLAME BUR FLARE AND BEVEL FINISHING

MAXILLARY POSTERIOR THREE QUARTER
CROWN
 THE MIDSAGITTAL INDEX: Adapt one half of
silicone putty over the tooth to be prepared plus
one or two adjacent teeth

OCCCLUSAL REDUCTION:
Make depth orientation cuts with ROUND –END
TAPERED DIAMOND BUR on the triangular
ridges and major developmental grooves of
occlusal surface.
Recommended range being 1-1.5 mm with 1.5 mm on
the functional cusp.

FUNCTIONAL CUSP BEVEL
Begin the functional cusp bevel by placing three to
five depth orientation grooves 1.5 mm deep using
a ROUND END TAPERED DIAMOND and NO. 171
BUR. The bur is held at 45 degrees to the long
axis of the preparation. It should extend from
the central groove on the proximal surface
around to the central on the other proximal
surface

LINGUAL AXIAL REDUCTION:
While reducing the lingual surface with a TORPEDO
DIAMOND be careful not to over incline the
lingual wall.

PROXIMAL AXIAL REDUCTION:
SHORT NEEDLE- Breaking of contact
TORPEDO DIAMOD- Reduction.
As the axial reduction is done, a CHAMFER finish
line is formed. This also serves as a guide to
producing adequate axial reduction.
The removal of tooth structure near the finish
margin should equal to one half of the diameter
of the diamond or 0.5 mm.

PROXIMAL GROOVES:
TAPERED FISSURE BUR
They are directed to the
opposite lingual corner of
the tooth forming a lingual
hook.
They must be placed as
FACIALLY AS POSSIBLE
without undermining the
facial enamel. They should
parallel the long axis of
the tooth

The groove is extends gingivally to about 0.5 mm above the
chamfer finish line.
The proximal groove should have a definite LINGUAL WALL
( retention to lingual tipping). They must be directed toward
the middle of the tooth at right angles to the outer surface
of the tooth ( prevents undermining of facial enamel and
avoids sharp unsupported wings of tooth structure).
The distal groove should be cut so that it parallels the mesial
groove.

OCCLUSAL OFFSET: tapered fissure bur.
It is a 1.0 mm wide ledge or flat terrace on the
lingual incline of the facial cusp. It connects the
grooves and assuming the shape of an inverted ‘V’.
It helps in casting rigidity by tying together the
proximal grooves to form a reinforcing staple.
Finish it with a end cutting bur

FACIAL BEVEL:
FLAME DIAMOND AND TAPERED FISSURE BUR
Place a narrow occlusal finish bevel of 0.5mm width
along the occlusofacial line angle taking care to
keep it perpendicular to the path of insertion
The bevel, both flares and the chamfer should
connect smoothly to form one continuous finish
line without sharp angles.

VARIATIONS:
Proximal boxes instead of grooves:
This design is employed especially in cases where
caries or previous restorations are already
present on the proximal surface. This design is
more retentive than the classic design.
Two proximal grooves:
This design is used to augment retention and
resistance and it is not as destructive a design as
a proximal box.

MANDIBULAR POSTERIOR THREE QUARTER
CROWN
It is indicated as a bridge retainer or single tooth
restoration on second premolars and molars for
patients who do not object to displaying some
metal.
-How the preparation differs form its maxillary
counterpart?
1. Here the facial cusps are the functional cusps
2. Hence the functional cusp bevel is placed on the
buccal cusp.
3. Occlusal shoulder is placed.
4. Facial bevel is placed.

THE SEVEN EIGHTHS CROWN
.
It can be judiciously applied on many maxillary and mandibular
molars and premolars.
Indications and advantages:
Excellent esthetics as compared to full coverage.
Significantly better retention and resistance than does the
three quarter crown.
Considered for a bridge retainer on an abutment with short
crown length
Also considered as a retainer for bridges whose span
exceeds one pontic when the greater retention of a full
coverage retainer is not needed but esthetics is a
consideration.

This preparation is suitable on teeth having an intact
mesiofacial cusp but restoration, caries, decalcification or
fracture of the distofacial cusp

THE PROXIMAL HALF CROWN
INDICATIONS:
1.TILTED MAN.MOLAR/
PREMOLAR ABUTMENT
2.THE DISTAL SURFACE IS CARIES FREE
3.MINIMAL INTERPROXIMAL CARIES ELSEWHERE

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