Tooth preparation for full veneer crowns /certified fixed orthodontic courses by Indian dental academy

TOOTH PREPARATION FOR
FULL VENEER CROWNS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


CONTENTS OF THE SEMINAR
Introduction and history of full veneer crowns
Terminologies
Rotary Instruments used for tooth preparation
Preparation for full veneer crowns
a. Complete cast metal crown
b. Anterior metal ceramic crown
c. Posterior metal ceramic crown
d. Porcelain jacket crown
e. Cast ceramic crown
Review of literature
Conclusion
References

INTRODUCTION
Tooth preparation is a far more important
phase of fixed partial denture prosthesis
treatment although some practitioners never
realize this. It must be done with skill and
meticulous attention to detail, for everything
else that follows – pulpal vitality, periodontal
health, a good esthetic result, proper
occlusion, protection of remaining tooth
structure, and the longevity of the
restoration itself – will depend on it.

HISTORY
Although fixed prosthodontic crown and
bridge work dates to as back as 300 to 400 BC
where in one of the oldest tombs of Sidon, a
Phoenician specimen was found consisting of
gold wire fastened around six anterior teeth, two
of them being pontics.
But crown and bridge fixed partial
prosthesis was indeed in a crude state of
development till as late as 1850.
The early crown were not fabricated by
casting. It was made by flowing solder over gold
foil that had been adapted to the tooth
preparation, with wrought wire staples in the
preparation grooves. Inlays were made in a
similar fashion by flowing solder into a foil matrix
adapted to the cavity preparation.

TOOTH PREPARATION FOR
FULL VENEER CROWNS


The significance of tooth preparation grew
steadily as technology made possible an
increasingly accurate fit of cast restorations.
With improvement in the technology of
fabricating restorations, there was a tremendous
increase in the complexity of restoration designs
and in the demands placed on retainers by more
sophisticated prostheses.
During the same time period that new types
of all-metal restorations were evolving, efforts
were being made to produce restorations that
could restore the patient esthetically as well as
functionally.

A major step in this direction was the
development of the porcelain jacket crown by
Land in 1886 when low-fusing porcelain fused in
a gold matrix made its appearance.
In 1907 William H. Taggart announced his
method of making gold castings, using a
disappearing wax pattern. This application of an
old method revolutionized the technical aspect
of restorative dentistry. It made possible
exceptional refinements in the construction of
fixed partial prosthetic appliances.

From the beginning, restorative dental
procedures have been limited far more by the
technology available than by a lack of ingenuity
on the art of dentists.
These technological improvements have
not
decreased
the
need
for
skilled,
knowledgeable restorative dentists. On the
contrary, they have made knowledge and skill
that much more critical. Technology in the hands
of a skilled operator makes it possible to do more
work of an even higher quality.

TERMINOLOGIES
Tooth preparation: is defined as the mechanical treatment of
dental disease or injury to hard tissues that restores a tooth to
original form. (Tylman)
Crown / artificial crown: a metal, plastic, or ceramic
restoration that covers three or more axial surfaces and the
occlusal surface or incisal edge of a tooth (GPT-7; 1999)
Full veneer crown / Complete crown: A restoration that
covers all the coronal tooth surfaces ( mesial, distal, facial,
lingual and occlusal ) (GPT-7; 1999)
Chamfer Finish line: A finish line design for tooth preparation
in which the gingival aspect meets the external axial surface at
an obtuse angle (GPT-7; 1999)
Shoulder finish line : A finish line design for tooth preparation
in which the gingival floor meets the external axial surfaces at
approximately a right angle(GPT-7; 1999)

Retention form : The feature of a tooth
preparation that resists dislodgement of crown in
a vertical direction or along the path of
placement (GPT-7; 1999)
Resistance form : The features of a tooth
preparation that enhance the stability of a
restoration and resist dislodgement along an
axis other than the path of placement (GPT-7;
1999)

Bevel : The process of slanting the finish line and
curve of a tooth preparation (GPT-7; 1999)

ROTARY INSTRUMENTS USED FOR
FULL VENEER PREPARATIONS
Shape
Round
end
diamond

Use
tapered 1.Depth orientation grooves
2.Occlusal reduction
3.Functional cusp

Torpedo diamond

1.Axial reduction
2.Chamfer finish line

Short needle

1.Initial interproximal axial
reduction in posterior teeth

Long needle

1.Initial
proximal
axial
reduction in anterior teeth

Small wheel diamond
Tapered
(171L)

fissure

1. Lingual reduction in anterior
teeth

bur 1.Seating groove
2.Proximal groove (posterior
teeth
3.Smoothing and finishing
4.Occlusal and incisal bevels


Tapered fissure
(169L & 170L)

burs 1.Initial groove alignment
2.Angles of proximal boxes
3.Smoothing and finishing
4.Occlusal and incisal bevels

End cutting bur

Conventional shoulder finishing

Torpedo bur

1.Axial wall finishing
2.Chamfer finishing

Flame bur

1. Flare and bevel finishing


FULL VENEER CROWNS
COMPLETE CAST
CROWN

METAL CERAMIC

ALL CERAMIC CROWN


COMPLETE CAST METAL CROWNS
Complete cast metal crowns can be
used where the break down of tooth
structure is severe, to the extent that is
has been described in operative dentistry
as “the final attempt to preserve the
tooth”. The terms “full crown”, “full cast
crown” and “complete crown” can be
used interchangeably with full veneer
crown to describe a restoration entirely
made of cast metal.

Clinicians have long considered full veneer crowns
to be the most retentive of veneer preparations
Controlled laboratory studies have shown that
when compared with partial veneer designs, the
full veneer crown exhibits superior retention and
resistance
It does not mean that it must be used in every
case
Instead should be used on those teeth whose
restoration demands maximum retention.
Selection of full veneer retainer becomes
mandatory when the abutment tooth is small or
when the edentulous space is long.

Indications
Extensive destruction from caries or trauma.
Endodontically treated teeth.
Existing restoration that needs the use of a more
conservative restoration
Necessity for maximum retention and strength.
To provide contours to receive a removable appliance.
Other re-contouring of axial surfaces (minor corrections
of malinclinations).
Correction of occlusal plane.
Contraindications
Should not be used in mouths with uncontrolled caries
Less than maximum retention necessary.
Esthetics.

Advantages
Strong.
High retentive qualities.
Usually easy to obtain adequate resistance
form.
Option to modify form and occlusion.
Contact areas can be conveniently developed.
Embrasure areas can be enhanced for
periodontally compromised dentition.
Disadvantages
Removal of large amount of tooth structure.
Adverse effects on tissue.
Vitality testing not readily feasible.
Display of metal.

TOOTH PREPARATION FOR COMPLETE CAST CROWN
Planar occlusal reduction is
done using round end tapered
diamond and no: 171 bur. Depth
orientation grooves are made on
the triangular ridges and primary
developmental
grooves.
The
depth orientation grooves should
be 1.5mm deep on functional
cusps and 1mm deep on nonfunctional cusps. The tooth
structures between the orientation
grooves are removed following
cuspal contours.

Functional cusp bevel is
done using round end
tapered diamond and no:
171 bur. Depth orientation
grooves are placed across
the facial occlusal line
angle of the mandibular
molar. The bevel should
parallel the inward facing
inclines of the cusps of
the opposing tooth, at a
depth of 1.5 mm usually
forming a 45° angle with
the axial wall.

Facial and lingual axial
reduction is done with a
torpedo
diamond
producing a definite
chamfer finish line at the
same time. The facial
and lingual reduction are
carried as far as possible
into the interproximal
embrasures
without
nicking the adjacent
teeth.

Mesial and distal axial
reduction. A short thin
tapered diamond is placed
against the facial surface
of
the
remaining
interproximal
tooth
structure. It is held upright
and moved up and down,
directing it lingually with
light
pressure.
Once
sufficient space has been
produced, sweep the short
thin diamond back and
forth planing the surface to
smoothness.

Chamfer finishing.
Torpedo bur is used to
produce a distinct
finish line and to
round of the angles of
the preparation.


Seating groove is made
on the axial surface
using no: 171 bur. The
groove should be cut to
the full diameter and it
should extend gingivally
to a point 0.5 mm above
the chamfer.


Features of full veneer crown preparation and
the function served by each


METAL CERAMIC RESTORATION


The use of porcelain fused to metal
restorations
has
grown
from
the
development of the first commercially
successful porcelain/ gold alloy restoration
by Weinstein et al in 1950’s. While a
porcelain-fused to metal crown can serve as
a strong and esthetic restorations, patients
too often receive this type of restoration for
minor irregularities that could have been
better handled by conservative treatment or
none at all.

ANTERIOR METAL-CERAMIC CROWN
Indications
• Esthetics
• Need to incorporate occlusal or cingulum
rests
• If
porcelain
jacket
crown
is
contraindicated.
Contraindications
• Large pulp chamber.
• Intact buccal wall.
• When more conservative retainer
technically feasible.

is

Advantages
• Superior esthetics as compared to cast gold
restoration.
• Retentive qualities are excellent
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Disadvantages
Removal of substantial tooth structure.
Subject to fracture because porcelain is brittle.
Difficult to obtain accurate occlusion in glazed
porcelain.
Shade selection can be difficult
Inferior esthetics compared to porcelain jacket
crown.
Expensive.

ANTERIOR PORCELAIN FUSED TO
METAL CROWN PREPARATION
Depth orientation grooves: A
flat end tapered diamond is first
aligned with the incisal portion of
the facial surface and two
vertical cuts are made to the full
diameter of the diamond fading
out at the “break” where the
curvature of the facial is the
greatest. Three similar grooves
are made maintaining the same
instrument parallel to the gingival
segment of the facial surface.
Two incisal orientation grooves
2.0 mm deep are made.

Incisal reduction: A
flat
end
tapered
diamond is used to
reduce the incisal
edge by 2.0 mm
keeping the plane of
the reduced surface
parallel to the former
incisal edge. A round
wheel diamond may
also be used for
incisal reduction.

Facial reduction,
incisal half: A flat
end tapered diamond
is used to remove the
tooth
structure
remaining
between
the orientation groove
in the incisal portion
of the facial surface.

Facial reduction, gingival
half: A flat end tapered
diamond is used to reduce the
gingival segment and extend
well into the proximal surface.
1.2 mm to 1.4 mm is the
accepted reduction for a
porcelain fused to metal
restoration. If there is sound
tooth structure interproximaly a
vertical wall or “wing” of it, is
left
standing
in
each
interproximal area lingual to the
proximal contact.

Lingual reduction: A
small round diamond
with a head 1.4 mm in
diameter is used to
make
four
depth
orientation cuts. A small
round wheel diamond is
used create a concave
surface over the lingual
surface of the tooth
incisal to the cingulum.

Lingual axial reduction is
done with a torpedo diamond
producing a definite chamfer
finish line at the same time. If
there
is
limited
space
between the facio proximal
angle of the wing and the
proximal surface of the
adjacent tooth, use a long
needle diamond to reduce the
axial wall lingual to the wing.
The lingual axial wall should
be parallel with the cervical
one third of the facial surface.

Facial axial finishing:
No: 171 bur is used to
smooth the entire facial
surface and round over
any sharp angles on
the incisal angle or
along the edges.


Shoulder finishing:
No: 957 bur is used to finish the shoulder.


The features of an anterior porcelain fused to
metal crowns preparation on an anterior tooth


POSTERIOR PORCELAIN FUSED TO
METAL CROWN PREPARATION


Appearance zone
Maxillary

- premolars
- first molars

Mandibular – first premolar


POSTERIOR PORCELAIN FUSED TO METAL
CROWN PREPARATION
Planar occlusal reduction
is done using round and
171 bur. Depth orientation
grooves are made on the
triangular
ridges
and
primary
developmental
grooves.
The
depth
orientation grooves should
be 1.5 to 2.0 mm in occlusal
areas
where
porcelain
coverage is required. The
tooth structures between the
orientation
grooves
are
removed following cuspal
contours.

Functional cusp bevel
is done using round end
171
bur.
Depth
orientation grooves are
placed across the lingual
incline of the maxillary
lingual cusp. The bevel
should parallel the inward
facing inclines of the
cusps of the opposing
tooth, at a depth of 1.5
mm usually forming a 45°
angle with the axial wall.

Depth orientation grooves
A flat end tapered diamond is
first aligned with the occlusal
portion of the facial surface
and three vertical cuts are
made to the full diameter of
the diamond, fading out at the
“break” where the curvature of
the facial
surface is the
greatest. Two similar grooves
are made maintaining
the
same instrument parallel to
the gingival segment of the
facial surface. A single depth
orientation groove may also
be used.

Facial reduction, occlusal half: A flat end
tapered diamond is used to remove the
tooth structure remaining between the
orientation groove in the occlusal portion
of the facial surface.


diamond is used to reduce
the gingival segment and
extend
well
into
the
proximal surface. 1.2 mm
to 1.4 mm is the accepted
reduction for a porcelain
fused to metal restoration.

Proximal axial reduction:
Short needle diamond facilities
interproximal reduction with out nicking the
adjacent tooth. Once separation between
the teeth is achieved the needle diamond is
used to plane the proximal axial wall.


Lingual axial reduction: A torpedo
diamond is used for lingual axial
reduction and to round over the corner
created at the line angle with the
proximal surfaces.


Axial finishing: All axial
surfaces to be veneered with
metal are finished using a
torpedo
finishing
bur
producing the chamfer finish
line. The facial surface and
those areas of the proximal
surfaces to be veneered with
porcelain are smoothened with
the no: 171 bur. Lingual to the
proximal contact, the transition
from
the
deeper
facial
reduction to the relatively
shallower
lingual
axial
reduction result in a vertical
wall or “wing” of tooth
structure.

Shoulder finishing: No: 957 bur is
used to finish the shoulder and is
planed with a sharp 1.0 m wide chisel.
Gingival bevel: Flame diamond and
finishing bur are used to produce a
narrow bevel, no wider than 0.3 mm.


The features of a posterior porcelain fused to metal crown
preparations for a porcelain fused to metal crown on an
posterior tooth and the function served by each.


ALL-CERAMIC CROWNS


The all ceramic crown differs from other ceramic veneer
restorations because it’s not cast in gold or some other
metal
It is capable of producing the best cosmetic effect of all
dental restoration. However since it is entirely made of
ceramic, a brittle substance, it is more susceptible to
fracture.
For many years the only type of all ceramic crown was
the porcelain jacket crown, which was built up in
increments over a matrix or shell formed by thin platinum
foil adapted to a cast or die of the prepared tooth. A lot of
recent advances have improved the properties of dental
porcelain.
However more than any other restoration all ceramic crown
depends for its very survival on the tooth preparation
beneath. Tooth support is more critical for fracture
resistance of the restoration than is the bulk of
porcelain.

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Indications
High esthetic requirement.
Considerable proximal caries.
Incisal edge reasonably intact.
Endodontically treated teeth with post-and –
cores.
Favourable distribution of occlusal load.
Contraindications
When superior strength is warranted and
metal-ceramic crown is more appropriate.
Significant caries with insufficient coronal tooth
structure for support.
Thin teeth faciolingually.
Unfavourable www.indiandentalacademy.com
distribution of occlusal load.

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Advantages
Excellent esthetics
Good tissue response even for subgingival
margins.
Slightly more conservative of facial wall than
metal ceramic
Brittle nature of material.
Can be used as single restoration only.
Disadvantages:
Reduced strength compared to metal ceramic
crown.
Proper preparation extremely critical
Among least conservative preparations
Brittle nature of material
Can be used as single restoration only

PORCELAIN JACKET CROWN PREPARATION
Depth orientation grooves: A
flat end tapered diamond is first
aligned with the incisal portion of
the facial surface and two vertical
cuts are made to the full diameter
of the diamond, fading out at the
“break” where the curvature of the
facial surface is the greatest.
Three similar grooves are made
maintaining the same instrument
parallel to the gingival segment of
the facial surface. Two incisal
orientation grooves 2.0 mm deep
are made.

Facial reduction,
incisal half: A flat end
tapered diamond is
used to remove the
tooth
structure
remaining between the
orientation groove in
the incisal portion of
the facial surface.

diamond is used to reduce
the gingival segment and
extend
well
into
the
proximal surface. Extend
the facial reduction through
the proximal surfaces with
the flat end tapered
diamond producing
a
shoulder in the process.

Lingual reduction: A
small round diamond
with a head 1.4 mm in
diameter is used to
make
four
depth
orientation cuts. A small
round wheel diamond is
used to create a
concave surface over
the lingual surface of
the tooth incisal to the
cingulum.

Lingual axial
reduction:
A flat
end
tapered
diamond
is
employed for axial
reduction to prepare
the vertical lingual
wall.
Blend
the
reduction of each
axial surface with
that on the adjacent
axial surface.

Axial finishing: No:
171 bur is used to
smooth the axial
surfaces and to
round
all distinct
positive angles on
the preparation.


Shoulder finishing: No:
957 bur is used for
preparing a smoothly cut
shoulder perpendicular
to the line of force or to
the long axis of the
tooth.


The features of all ceramic crowns preparation for a
porcelain jacket crown on an anterior tooth and the
function served by each.


CAST CERAMIC CROWN PREPARATION
Occlusal reduction: A
large round end tapered
diamond is used to place
depth orientation grooves
on triangular ridges and
major grooves. The final
occlusal reduction should
be 1.5 mm to 2.0 mm
deep. Remove the tooth
structure
remaining
between
the
depthorientation grooves with
the
large
round-end
tapered diamond. www.indiandentalacademy.com

Functional cusp bevel:
The large round end
tapered diamond is used
to
produce
depth
orientation grooves in
the facial incline of the
facial cusp. A minimum
of 1.5 mm of clearance
is necessary.


Facial and lingual axial
reduction: The large round
end tapered diamond is used
to obtain axial reduction
ranging from 1.0 to 1.5 mm
by making depth orientation
grooves and removing the
tooth
structure
between
them. The axial reductions
are carried out as far as
possible into the proximal
embrasures.

Complete axial reduction: A short needle
diamond is used to begin the proximal axial
reduction without touching the adjacent tooth.
The axial reduction interproximally is
complete by running the round end tapered
diamond.


Preparation finishing: round end
tapered carbide bur is used to finish the
axial surfaces and the functional cusp
bevel.


The features of a cast ceramic crown preparation for
an all ceramic crown on a posterior tooth and the
function served by each.


REVIEW OF LITERATURE


Dennis et al (1974) – while describing the
fundamentals of tooth preparation, stated
thatAll preparations require the incorporation of
factors to prevent the dislodgement of the
restoration by functional stresses. Retention
form counteracts the tensile stresses, and
resistance form counteracts the shearing
stresses. A preparation with resistance form
will be retentive; the opposite is not
necessarily true. The same method is often
used when incorporating the factors of both
retention and resistance form.

Thus, for practical purposes, these factors can be
considered together as:I. Principles1. Parallelism
2. Length
3. Surface area
II. Factors-

and c

1. Primary factors- axial surfaces
2. Secondary factors:
a. Groove
b. Box
c. Pinholes
d. combinations of a,
b,

David A. Felton et al (1987) found that
teeth prepared for full crowns by using
diamond burs will have 31% greater
retention than preparations made with
carbide bur. Alternative retentive features
should be considered in preparation
design if carbide burs are used.


Shillingburg HT et al (1987) - stated that
theoretically,
the
most
retentive
preparation would be with parallel walls.
However in order to avoid undercuts and
allow complete seating of the restorations
during cementation, the walls must have
some taper. One which lies within the
range of 2 to 6.5 degrees has been
considered to be optimal

Jeffrey Nordlander et al (1988) studied
the convergence angles of full coverage
preparations performed
in a clinical
environment and concluded that the ideal
convergence of 4 to 10 degrees is seldom
achieved. The mean convergence angle
of mandibular preparations were greater
than mean maxillary convergence angle
and premolar convergence angle tended
to be smaller than anterior convergence
angles.

Gerard Byrne (1992) compared shoulder,
shoulder bevel and chamfer finish
configurations and studied their effect on
fit of cemented complete crowns. He
observed that
Incisor cast crowns did not seat
completely regardless of finish line design
Finish line form did not affect the fit of
incisor cast crowns (cemented or not )


El Mowafy OM et al (1996) - investigated the
effect of varying crown preparation taper and
height on the retention in metal ceramic crowns
cemented with zinc phosphate cement and resin
cements. They reported significantly higher
retention in both Standard (24 degree TOC and
a constant height of 4.0±0.25mm) and Conical
preparation (with same height but TOC 70
degree) cemented with resin cement than the
zinc phosphate cement. They also reported
significantly higher retentive force for the crowns
of Conical preparations cemented with resin
cements than that of the crowns of Standard
preparation cemented with zinc phosphate
cement. Also short crowns cemented with resin
cement had significantly higher retention force
than long crowns cemented with zinc phosphate

Mohammed F. Ayad et al (1997) studied
the
relationship
between
surface
characteristics of teeth prepared for
complete cast crowns and retention of
restorative
cemented
restorations.
Greatest retention value was for tooth
preparations refined with carbide burs and
cemented with Panavia-EX, an adhesive
resin cement. Least retention values was
for teeth preparations completed with
finishing bur and luted with zinc phosphate
cement.

Charles J. Godacre et al (2001) –
Reviewed literature covering 250 years of
clinical practice with emphasis on scientific
data acquired during last 50 years. On the
basis of the current scientific studies, they
proposed certain guidelines for preparing
teeth for complete crowns


Omar Zidan et al (2003) - studied the relation
between the preparations’ taper and retentive
capacities of conventional zinc phosphate cement,
glass ionomer cement and adhesive resin cements.
They concluded that:
The retentive values of adhesive resin cements
at 24 degree taper is 20% higher than the retentive
values of the conventional zinc phosphate and glass
ionomer cements at 6 degree taper
Increasing taper of the preparations from 6 to 12
degrees did not affect the retention of the crowns
within the different cement groups. The choice of the
cement for crown prepared within this ideal range of
taper might be of limited clinical value
Increasing the taper to 24 degrees decreases
the retention of crowns significantly.

CONCLUSION
1. The total occlusal convergence (TOC), formed
between two opposing axial surfaces, ideally ranges
from 10 to 20 degree.
2. 3 mm should be the minimal occluso-cervical / incisocervical dimension of the incisors and premolars
prepared with recommended 10 to 20 degree total
convergence
3. The minimal occlusal cervical dimension of molars
should be 4 mm when prepared with 10 to 20 degrees
TOC.
4. The ratio of the occluso-cervical/inciso-cervical
dimension of a prepared tooth to the facio-lingual
dimension should be at least 0.4 or higher for all teeth
5. Facio proximal and linguo proximal line angles should
be preserved wherever possible.

6. When the above features are missing the teeth
should be modified with auxiliary resistance features
such as axial grooves or boxes, preferably on
proximal surfaces.
7. Many molars need auxiliary grooves or boxes to
enhance resistance form because of their short
occluso- cervical dimensions and the unfavorable
ratio of the occluso- cervical dimension to the
faciolingual dimensions
8. The type of finish line selected for use with metalceramic crowns should not be based on marginal fit
but on the type of crown/ retainer, esthetic
requirements, ease of formation and personal
preference.
9. Expectations of enhanced marginal fit with certain
finish lines could not be validated by recent research.

10.Esthetic requirements and tooth conditions
determine finish line locations relative to the gingiva
with a supra gingival location being more
acceptable.
11.When sub gingival finish lines are required, they
should not be extended to the epithelial attachment
12.Line angle should be rounded, and reasonable
degree of surface smoothness is desired.
13.Both shoulder and chamfer finish lines can be used
with all-ceramic crowns if the crowns are bonded to
the prepared teeth. Depths greater than 1 mm are
not required when a semi translucent type of allceramic crown is used.
14.Chamfer finish lines approximately 0.3 mm deep
are well suited for all-metal crowns

15.Axial and occlusal reductions for all-metal crowns
should be at least 0.5 mm deep and 1,0 mm deep,
respectively. For metal-ceramic crowns, facial/axial
reductions in excess of 1 mm can compromise the
remaining tooth structure external to the pulp,
whereas 2.0 mm of occlusal reduction is commonly
achievable even on a young tooth. Two millimeters
incisal/occlusal reduction is recommended for allceramic crowns.
16.Line angle should be rounded on all-ceramic tooth
preparation to reduce stress in the definitive
restoration. With crowns that use metal, the primary
purpose of line angle rounding is to facilitate pouring
impressions and investing wax patterns without
trapping air bubbles and to facilitate removing
casting nodules

17.Smooth tooth preparation appears to enhance the
fit of restorations. Surface roughness generally
increases retention with zinc phosphate cement, but
its effect with adhesive cements ( polycarboxylate,
glass ionomer, resin) has not been as definitely
determined. A reasonably smooth preparation is
therefore recommended.


REFERENCES


El Salam Shakal MA, Pfeiffer P, and Hilgers RD. Effects of
tooth preparation design on bond strengths of resin bonded
prostheses; a pilot study. J Prosthet Dent. 1997; 77: 243249.
Felton DA, Ed Kanoy B and White JT. The effect of surface
roughness of crown preparations on retention of cemented
castings. J Prosthet Dent. 1987; 58: 292-296.
Nordlander J Weir D, Stoffer W and Ochi S. The taper of
clinical preparations for fixed prosthodontics. J Prosthet
Dent. 1988; 60: 148-151.
Byrne G. Influence of finish-line form on crown cementation. Int.
J Prosthet Dent. 1992; 5: 137-144.
Rouse JF. Full veneer versus traditional veneer preparation. A
discussion of interproximal extension. J Prosthet Dent. 1997;
78: 545-549.
Charles Goodacre, Wayne V. Campagni, and Steven A.
Aquilino, -Tooth preparation of complete crown: An art form
based on scientific principle.JProsthet.Dent2001; 85:363-76
El-Mowafy O.M., Fenton A.H.,Forester N., Milenkovice M.Retention of metal ceramic crowns cemented with resin
cement :effects of preparation taper ,,and height –
J.Prosthet.Dent 1996;76:524-29.

Omar Zidan and Gerry C. Ferguson – The retention
of complete crowns prepared with three different
tapers and luted with four different cements, J.
Prosthet.Dent. 2003;89:565-71
Ayad MF, Rosenteil SF and Salama M. Influence of
tooth surface roughness and type of cement on
retention of complete cast crowns. J Prosthet
Dent. 1997; 77: 116-121.
Fundamentals of tooth preparations for cast metal and
porcelain restorations. Shillinburg HT Jr.
Quintessence Publishing Co. Inc. 1987
Contemproary Fixed Prosthodontics. Rosenstiel
Tylman’s Theory and Practice of fixed prosthodontics.
8th edition. All India Publishers and Distributors

THANK YOU


Samuel E. Guyer. (1970) discussed the
types and modifications of the four
elements of tooth preparation 1. Occlusal
reduction, 2. Axial reduction, 3. Margins,
4. Means of retention and resistance form.
He has applied these 4 principles on
multiple tooth preparation which involves
three steps: 1. Occlusal reduction, 2. Axial
reduction, 3. Retention of resistance form
placement. He has introduced guidelines
for grouping of teeth for multiple
preparations.

J.R. Gavelis et al (1980) discussed the
influence of marginal design of a full crown on
the occlusal seat and marginal seal of a
cemented full crown restorations. Feather edge
and parallel bevel demonstrated the
best
marginal seal, followed by full shoulder, 45
degree shoulder, and finally 90 degree shoulder
with 30 degree and 45 degree bevels. The 90
degree shoulder demonstrated best seating
followed by 45 degree shoulder, 90 degree
shoulder with 45 degree bevel, feather edge, 90
degree shoulder with 30 degree bevel, chamfer
with parallel bevel and degree shoulder with
parallel bevel.

H. W. Anslem Wiskott et al (1997)
investigated the relationship between
tooth preparation height and diameter and
the resistance of cemented crowns to
dynamic
loading.
The
relationship
between abutment height and resistance
to dynamic lateral loading was found
approximately linear and crowns luted
using resin composite cement were the
most resistant.

Julia Fischer et al (1997) described a
new restoration method the edge up
technique that enables the correction of
defects in the anterior teeth with maximum
preservation of tooth substance. The
special preparation method involves a
circular extended shoulder preparation in
the enamel or an angle preparation using
a special preparation kit.

Jung-Zen Syu et al (1993) Evaluated
axial and marginal fit of crowns made for
three tooth preparations that had different
labial finish lie configurations: shoulder,
shoulder-bevel
and
chamfer.
No
significant differences were found among
the group for marginal or axial gaps crown
fit was not influenced by any of the three
finish lines and castings with well fitting
margins exhibited measurable axial wall
space.

Tooth preparation for full veneer crowns /certified fixed orthodontic courses by Indian dental academy

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