class II cast metal restorations

CLASS II CAST METAL
RESTORATION
BY
Dr. MALIHA MUNEER
PGR
OPERATIVE DENTISTRY
NID MULTAN

Introduction
Indications and contraindications
Advantages and disadvantages
Tooth preparation

Interocclusal records
Temporary restoration
Trying-in the casting
Cementation

“Life size likeness of some
desired form”
“To produce a shape by
thrusting a molten liquid or
plastic material into a mold
possessing the desired shape”

“ Something that has been cast in a
mold; an object formed by the
solidification of a liquid that has been
poured or injected in a mold”

“Any strong relatively ductile
substance that provides
electropositive ions to a corrosive
environment and that can be
polished to a high luster”

Restoration which is constructed
out of the mouth from materials
like gold alloys ,and then
cemented back into the prepared
teeth

“An Inlay is an intracoronal restoration
designed mainly to restore occlusal
and proximal surfaces of the posterior
teeth without involving the cusps of
the teeth”

“ An Onlay is a combination of
intracoronal and extracoronal cast
restorations when one or more
cusps are covered"

OVERLAY
“ An overlay is an indirect
restoration which incorporates
a cusp or cusps by covering
or over-laying the missing
cusps”

Was the first to introduce inlay in
dentistry who gave the concept of
forming an investment around a
wax pattern, eliminating the wax,
and filling the resultant mold with
a gold alloy
Dr.Philbrook in 1987

In 1907 Taggart
Changed the practice of
restorative dentistry by introducing
his technique for cast gold dental
restorations

Until recently
Gold-based alloys have been the
only ones used for cast dental
restorations
The ADA sp#5 still requires 75% of
gold-plus-platinum group metals to
be present in alloys for cast
restorations

According to Sturdevant there are
four distinct groups of alloys
The traditional high gold alloys
Low gold alloys
Palladium-silver alloys
Base metal alloys

MATERIAL USED FOR CAST
RESTORATION
Class I Gold and Platinum based alloys.
These are type I,II,III,IV gold alloys.
Class II Low gold alloys containing gold less
than 50%
Class III These are non gold palladium based
alloys
Class IV Nickel-Chromium based alloys
Class V Castable or moldable ceramics

Corrosion
resistance
A)Mechanism of
corrosion
resistance
B)Composition of
different elements

A)Mechanism of
corrosion
resistance
Immune
systems
Gold
systems
Gold
substitute
systems
Passivating
systems
Nickel-
Chromium
Cobalt-
Chromium
Iron-
Chromium
Titanium
systems

B)Composition
of different
metals
Noble
metal
alloys
Gold
Platinum
Palladium
Rhodium
Iridium
Ruthenium
Osmium
Precious
metal
alloys
Include
all of
noble
metals
and
silver
Low gold
alloys
Gold
Platinum
Palladium
Gold
substitute
alloys
Ag-Pd
Systems
Pd
systems
Base
metal
alloys
Ni-Cr
Co-Cr
Ti -
systems

ADA classification system for gold
casting alloys
I Compositions are intended for small inlays
that don’t involve significant occlusal loads
IV
III
II
Intended for crowns, bridges and
removable partial dentures
Intended for onlays and crowns
Intended for inlays and onlays

INDICATIONS
Large restorations
Restoration of endodontically
treated teeth
Teeth at risk for fracture

Correction of occlusion plane
and diastema closure
Support for partial or complete
denture

CONTRAINDICATIONS
High caries rate
Young patients
Esthetics
Small restorations

ADVANTAGES
Strength
Biocompatibility
Low wear
Control of contours & contacts

DISADVANTAGES
More number of appointments &
higher chair time
Temporary restoration
Technique sensitive
Splitting forces

Occlusion:
The occlusal contacts in maximum intercuspation
where the teeth are brought into full interdigitation

The occlusal contacts that occur during
mandibular movements
Canine guidance
Group function

 LA of the tooth to be prepared as well
as adjacent soft tissues eliminates pain
and reduces salivation making procedure
pleasant for patient and the operator
Anesthesia:

 Select the method that will be
used to fabricate the temporary
restoration
 Preoperative impression is required
to reproduce the occlusal, facial
and lingual surfaces of the temporary
restoration to the preoperative
contours
Consideration for temporary restoration:

Preservation
of tooth
structure
Retention
and
resistance
Structural
durability
Preservation
of the
periodontium
Marginal
integrity

Preservation of tooth structure
In addition to replacing lost tooth
structure, the cast restoration
must preserve the remaining structure
Preservation of tooth structure
may involve limited amount of
tooth being prepared

Retention
Retention is the ability of the
preparation to impede removal
of the restoration along its path
of insertion

Four factors under the control of
operator which influence retention:
 Degree of taper
 Total surface area of the cement film
 Area of cement under shear
 Roughness of the tooth surface

Resistance
Resistance is the ability of the
preparation to prevent dislodgement of
the restoration by forces directed in an
apical, oblique, or horizontal direction
and prevents any movement of the
restoration under occlusal forces

Preparation
Path
Apico-occlusal
taper
Circumferential
tie

Prep should have a “Single Insertion
path”
Path is parallel to long axis of tooth
Helps in retention & decreases the
micro-movements of restoration
during function
Preparation Path:

Apico-Occlusal Taper:
For max retention, opposing walls &
axial surfaces should be perfectly
parallel to each other
Taper should be 2-5° from path of
prep

Slight divergence of opposing walls
in Intracoronal

Slight convergence of axial walls in
Extracoronal

Taper can be altered according to
following features
Length of prep and/or axial wall:
 Greater the length, more the taper
 Less the length, less taper

Need for retention:
 Greater the need of retention,
more will be the need to achieve
parallelism (thus less taper)

As the taper increases from 7-15 , stress
rises&retention decreases

The peripheral marginal anatomy
of the preparation is called as the
“Circumferential Tie”
Circumferential Tie:

Should fulfill the requirements advocated
by Noy:
 If the prep ends on enamel, the enamel
must be supported by sound dentin
 Enamel rods forming the cavosurface
margin should be continuous with sound
dentin & covered with a restorative
material

Preservation of the periodontal tissue
The casting should have proper
contact, embrasure form, occlusion
and a healthy occluso-gingival contour

Marginal Integrity
The margins must fit as closely
as possible against the finish line of
the preparation
They must have sufficient
strength
Whenever possible they should be
placed in an area where the dentist
can finish and clean them properly

Bevels:
“ Flexible extensions of a cavity
preparation, allowing the inclusion of
surface defects, supplementary
grooves and other areas on the tooth
surface”

Occlusal
PartialBevels
Types
Gingival
Long
Short Counter
Full
Hollow
ground

Involves part of the enamel only
Not used in cast restorations
Partial Bevel:

Includes entire enamel wall but no
dentin
Class I alloys ( Type 1 & 2 )
Short Bevel:

Includes all of the enamel wall and
up to one half of the dentinal wall
Most frequently used bevel for
cast materials
Long Bevel:

Includes all of the dentinal and enamel
wall
Well reproduced by all four classes of
cast alloys
Deprives preparation of internal
resistance and retention
Full Bevel:

When capping cusps this protects &
supports them
Given opposite to an axial wall on the
facial and lingual surfaces
Counter Bevel:

Allows more space for the cast
material bulk
Used to improve retention and
resistance to stresses
Hollow Ground (concave) Bevel:

Function of occlusal and gingival
bevels
Create an obtused angle marginal
tooth structure (strong tooth anatomy)
Produce an acute angled marginal cast
alloy (most amenable to burnishing and
finishing)

Makes it possible to decrease the
cement line by bringing the cast alloy
closer to the tooth
They are also a part of one of the
major retention form for cast
restorations

Primary Flare
Similar to a Long bevel
Specific angulation - 45° to the
Inner Dentinal wall proper

Functions and indications:
Perform the same function as bevels
Brings the facial and lingual margins of
the cavity prep to cleansable –
finish able areas
Indicated for the facial and lingual
proximal walls of an intra-coronal prep

Secondary Flare
It is always a flat plane superimposed
peripherally to a primary flare
Is prepared in a “Hollow Ground
Form” to accommodate the materials
with low castability
Has various angulations depending
on the involvement, extent and
function

Functions & Indications:
Bucco-lingual lesions, where
both walls are thinned ; the 1°
flare ends with an Unsupported
enamel
2 ° flare creates an obtuse angle of
marginal tooth structure (No sacrifice
to retention & resistance)

A 2° flare will accomplish this without
changing the 45° angulation
In broad contact areas or malposed
contact area, the 1° flare does not
bring the facial/lingual walls to
cleansable or finishable areas

Secondary flare to be omitted:
On mesiofacial proximal wall of
preparations on premolars and first
molars of the maxillary dentition for
esthetic reasons

Finish Lines For Tooth Preparation
Finish line/margin is the part of tooth
preparation/restoration that is in
close proximity to the periodontium
and that forms the most important
and weakest link in the success of
full coverage restorations
It is the outer edge of a crown, inlay,
onlay or other restoration

Finish
line
Supragingival
Subgingival

 Easily prepared & finished
 Impression can be easily made
 The patient can keep the area
clean easily
 Less destructive
 Restorations can be easily
evaluated at recall appointments
Supragingival

 Dental caries, cervical erosion or
restorations extend subgingivally
 The proximal contact area
extends to the gingival crest
Subgingival:

Biologic Width:
The combined height of connective
tissue and epithelium that isolates the
bone from the oral cavity
It is the distance considered necessary
for the existence of healthy bone and
tissue from the most apical extent of a
dental restoration

When restoration margin intrudes into
the biologic width, inflammation and
osteoclastic activity are stimulated

Finish
lines
Shoulder
Chamfer
Knife-
edge
Beveled
chamfer
Beveled
shoulder

It is a tapered preparation that has
maximum tooth reduction at occlusal,
incisal surfaces and tapers to zero
cutting at the gingival termination
Featheredge/chisel edge/shoulder less
cervical finish line

Easy to prepare
Conservative tooth preparation
Advantages:

 Overcontouring of restoration is
possible
 Decreased marginal adaptation
 Distortion of the margin is possible
during lab procedures as it is thin
 It is not a recommended finish line for
cast restoration
Disadvantages:

It is a marginal finish line either
curved or formed by a plane at an
obtuse angle to the external
surface of a prepared tooth
Chamfer Finish Line:

Ideal finishline for
Cast metal restoration

 Provides a slip joint
 Provides gingival area with
acceptable stress distribution
 Aids in accurate die trimming
 Adequate bulk and tooth contour
 Easy to prepare
Advantages:

 Less room cervically than shoulder
preparation, therefore, cannot prepare
with low speed cutting instrument
Disadvantages:

Shoulder Finish Line
When the external line angle of the
preparation is perpendicular to the
long axis of the tooth a shoulder finish
line results

 Least stress in cervical area
compared to other margins
 Better resistance to occlusal forces
 Bulk of material can be
accomodated
 Easy to identify margin and fabricate
wax pattern
Advantages:

 Increased retention
 Good marginal adaptation
 Less marginal distortion
 Easy to check seating of
restoration

 Least conservative of all the
other preparations
 Can cause adverse pulpal
involvement
Disadvantages:

Chamfer or shoulder with a bevel:
 Used by some who believe that a
bevelled margin is easier to detect
in an impression
 It makes the margins of the casting
more burnishable

Structural durability of the restoration
The casting must be rigid enough
not to flex and break the cement
film
Sufficient tooth structure must be
removed to create space for an
adequate bulk of restorative
material to accomplish this without
departing from the normal contours
of the tooth

 Occlusal reduction
 Axial reduction
Features that contribute to the
durability of the restoration

Correct occlusal reduction parallels
the major planes of the tooth

Flat, single plane occlusal reduction may
result in insufficient thickness of the
restoration over the grooves and fossae

Single plane reduction will result in
unnecessary loss of dentin over the pulp
horns and excessive shortening of the
axial walls with loss of retention

Functional cusp bevel paralleling the
opposing cusp allows for adequate
restoration thickness without undue
sacrifice of tooth structure

If the functional cusp bevel is omitted,
the restoration is likely to be too thin in
this stress-bearing area

If the restoration thickness is achieved
by overtapering the axial wall, retention
will be compromised

Absence of a functional cusp bevel, this
can result in superocclusion of the
restoration, which could only be
corrected by occlusal reduction of the
opposing tooth

General Rule:
Is to maintain the long axis of the
bur parallel to the long axis of the
tooth crown at all times
Whose crowns tilt slightly lingually,
the bur should tilt slightly lingually to
conserve the strength of the lingual
cusps

Initial penetration into the enamel
is done in a fossa with the edge
of the tip of a tapered fissure bur

Once a cut has been started, drag
the bur through the central groove
of the occlusal surface, leaning the
instrument in the direction the
handpiece is moving

Following any developmental grooves,
making the isthmus approximately 1.5
mm deep. The penetration should end
at least 1.00 mm from the nearest
occlusal contact

The completed occlusal outline is quite
narrow at this time.There is a distinct
dovetail extending into the facial groove,
which is placed to enhance resistance
and retention

In order to provide maximum resistance,
the pulpal floor should be flat, at an even
depth, and perpendicular to the path of
insertion of the preparation

Undermining marginal ridge: no.169 bur

Begin the proximal box by running bur
just inside the cemento-enamel junction
interproximally

In this proximal view, with the adjacent
tooth removed for better vision, it is
possible to see how far gingivally the
bur has been extended

The bur has been removed from the
preparation and superimposed over the
proximal surface to the full gingival
length to which the preparation was
extended

A sharp enamel chisel, such as
the hatchet used to break out
the undermined tooth structure

Proximal box: nos. 169 and 170 burs

Extend the bur facially and lingually to
the point where the box breaks contact
with the adjacent tooth.Create facial and
lingual line angles

Form the facial and lingual walls

Conflicts regarding taper of walls?
Parallel walls were advocated by early
authors
Ward was one of first to recommend
taper and prescribed a taper of 3-12
Gillett was in favour of 3 taper
Recently, Gilmore recommended 8-12
degrees

Widen the isthmus where it joins the
proximal box, rounding any angle that
may have formed in the area where
they meet

Enamel hatchet used to smooth and
define the facial and lingual walls of the
box

The completed proximal wall.The final
extension will be achieved when the
facial and lingual flares are produced

Plane the pulpal floor of the isthmus with
endcutting bur. The gingival floor of the
box should also be flat

Sharp gingival margin trimmer used to
create a V-shaped groove at the
junction of the axial wall & the gingival
floor of the box

Gingivo-axial groove sometimes
referred to as the “Minnesota ditch”
placed to enhance resistance to
displacement by occlusal forces

To start the flare, place the sharp-
tipped flame diamond in the proximal
box & use the small diameter tip to
cut the cavosurface angle of the box
from the gingival floor up

Continue occlusalward sweep of the
diamond without changing the angle or
direction of the instrument using the tip of
the flame diamond

With the adjacent tooth removed,narrow
flare is clear up to this point

It is now possible to use a larger portion of
the instrument, which can remove tooth
structure more efficiently

A sandpaper disk can be used for
shaping the flares, but extreme caution
must be used to prevent accidental
laceration of soft tissues

Lean the flame diamond over against
the pulpal axial line angle to produce a
proper bevel on the gingival floor

Blend the gingival bevel with the facial
and lingual flares to avoid a scooped-
out area, which would result in an
undercut

A bevel is placed around the entire
periphery of the occlusal portion of the
preparation

Carefully blend the proximal flares
with the occlusal bevel to produce a
smooth, continuous finish line

Bevel and flare finishing: flame bur

Use a flame-shaped carbide finishing
bur to go over the flares and the gingival
bevel

The flame shaped carbide finishing
bur is also used to refine the occlusal
bevel

An occlusal view of the completed
class II inlay preparation on a maxillary
molar

Inlay had a tendency to wedge the
cusps apart. Particularly with wide
isthmus.occlusal fore produce stresses
along sides and base, leading fracture
of the tooth

Onlay will distribute the force over a
wide area, reducing the potential for
breakage

Photoelastic stress analysis by Fisher
et al. The inlay produced very high
stress concentrations at the walls of the
isthmus and at the line angles

Onlay demonstrated very little stress

Planar occlusal reduction: round-end
tapered diamond and no.171 bur

The occlusal reduction is started by
placing depth-orientation grooves on
the occlusal surface. There should be
one along the crest of each triangular
ridge and one in each major
developmental groove

Depth-orientation grooves should be
1.5mm deep on the functional
cusp
1mm deep on the nonfunctional
cusp

On a maxillary tooth :
The depth of the orientation grooves
and occlusal reduction should be
0.5mm at the facio-occlusal line angle
to avoid unnecessary display of metal

Remove the remaining tooth structure
between depth-orientation grooves.
The reduction should follow the original
contours of the cusp

Functional cusp bevel: round-end
tapered diamond and no.171bur

Depth-orientation grooves should be
1.5mm deep at the cusp tip and fade
out along the line that will later mark
the location of the occlusal shoulder

Complete the reduction for the
functional cusp bevel by removing the
tooth structure remaining between the
orientation grooves

Smooth the planes of the occlusal
reduction and the functional cusp bevel
with the tapered fissure carbide bur

Visual inspection to assess reduction in
the facial half. On the lingual cusp can
be verified with red utility wax, or with a
thickness gauge

Occlusal shoulder 1mm wide extends
from the central groove on one proximal
surface to the central groove on the other
proximal surface

Either a chamfer(A) or an occlusal
shoulder(B) can be used for the occlusal
finish line on the functional cusp bevel

The isthmus is1.0 mm shallower than
on an inlay.The opposing facial and
lingual walls should be smooth, with
a minimum taper

Proximal box: nos.169L and 170 burs

The gingival floor should be
approximately 1mm wide

After completing the mesial box,
repeat the process with the distal box

The no.169L bur is used for forming
the facial and lingual walls and the line
angles of the proximal boxes

The bur is leaned slightly to form the
facial and lingual walls of the boxes.
facial and lingual walls that will diverge
occlusally, and axial walls will converge
occlusally

This occlusal view of the completed
boxes. The flares are added after the
boxes have been finished

A 1mm wide enamel chisel, used to
plane the facial and lingual walls of
the preparation

Planing horizontal surfaces: no.957 bur

Smooth the pulpal floor of the isthmus
that joins the proximal boxes

Smooth the occlusal shoulder on the
functional cusp bevel

Smooth the gingival floors of the
proximal boxes

Proximal flares: flame diamond and
flame bur

Place the flares on the proximal box form
within, starting with the tip of the flame
diamond, without scarring the adjacent
tooth

Enamel hatchet used to shape the
mesiofacial flare where esthetic
considerations are important

A sandpaper disk can also be used for
forming the flares. Be careful not to
cut the soft tissues

Gingival bevel: flame diamond and
flame carbide bur

Place a narrow bevel along the
entire gingival floor of the box. The
bevel should blend into the flares
on the facial and lingual walls of the
box, without forming an undercut

Lean the flame diamond over into
the proximal box to produce a
bevel that is not excessively long or
obtuse

Smooth the flares and the gingival bevel
with a flame-shaped carbide finishing
bur and produce a sharp, distinct finish
line

Facial and lingual bevels: flame
diamond and no.170 bur

The occlusal finishing bevel (0.5mm
width) is placed on the facial cusp
with bur held perpendicular to the
long axis of the tooth

Round the bevel on the facial flares.
Take care to make the outer edge of
the occlusal bevel (the actual finish
line) continuous with the outer edge of
the facial flare

Round over the line angle between the
occlusal reduction and the flare to
remove any other sharp projections that
might interfere with the complete seating
of the final cast restoration

Place a narrow (0.5mm) bevel on the
occlusal shoulder, making sure that it
also will blend smoothly with the lingual
flares where it joins them

Round over the angle between the
functional cusp bevel and the
flares

Occlusofacial view of the completed
MOD onlay preparation on a maxillary
premolar

An accurate registration of the normal
centric relationship of the maxillary and
mandibular arches. Also commonly
referred to as the bite registration
Occlusal Registration:

Requirements of bite registration material:
Dimensionally accurate after setting
Should be fluid in consistency during
recording to avoid pressure
Adequate working time
Short setting time

Patient’s left side
showing left working
side contacts (group
function)
Patient’s right
side showing
nonworking side

Non working side
Canine guidance
on working side

Wax bite
Useful when the diagnostic casts
are trimmed
The most common technique is
to use a softened baseplate wax

If sufficient
canine
guidance then
registration
can be
obtained by
Bite registration
pastes
Making full arch
impressions and
mounting on
articulator

ZOE paste has little to no resistance
to bite closure and is a fast-setting
material
Material is supplied in a paste system
and dispensed onto a paper pad,
mixed, and placed onto a gauze tray
for the patient to bite into it
Zinc oxide-eugenol (ZOE):

The material is fast setting
There is no resistance to biting
forces
There is no odor or taste for
the patient
It gains dimensional stability
over time
It is convenient to use
Polyvinylsiloxane bite registration paste

Commercially available bite registration
pastes and gauze-covered bite frame

Using cartridge dispenser and
disposable automixing tip, the base and
accelerator pastes are mixed and applied
to both sides of bite frame(2mm)

No portion of bite frame interferes with
closure, have patient to close in MI and
adjacent unprepared teeth touching in
their normal relationship

Remove carefuuly and inspect for
completeness

Mounted on semiadjustable
articulator are recommended
when restoring a large portion of
the patient’s posterior occlusion
with cast metal restorations
Full arch casts

Temporary restoration should satisfy
following requirements
Non-irritating and protect the
prepared tooth from injury
Protect and maintain the health
of the periodontium
Maintain the position of the
prepared, adjacent and
opposing teeth

Should provide for masticatory function
as indicated
Should have adequate strength
and retention to withstand the
forces to which it will be subjected

Temporary
fabricated by
Direct
technique
Intraorally directly
on the prepared
teeth
Indirect
technique
Outside mouth on
postop cast of
prepared teeth

Good marginal fit
Avoids placing polymerizing material
directly on freshly cut dentin and
investing soft tissues, reducing
irritation to these

Serves as an excellent guide for final
restoration when trimming and
contouring it
Avoids possibility of “Locking on”
the set temporary

Interior of tray coated with alginate
adhesive

Apply some alginate over and into
preparations with fingertip to avoid
trapping air

Impression is poured with fast-setting
plaster

Cut away thin edges of the preoperative
impression material that record gingival
sulcus

Trimming away much of the soft
tissue areas recorded by impression
and cast also facilitate seating

Trial seating the postoperative cast
into preoperative impression

Marking margins with red pencil

Applying release agent to cast

Fill preoperative impression with
temporary material in area of tooth
preparation

Seating cast into impression, taking
care not to overseat or tilt cast

Trim excess material back to accessible
facial and lingual margins (marked by
red line on plaster cast)

Refine interproximal embrasure
form with a diamond bur

On cast, cut away any tooth adjacent
to temporary

Trimming proximal surface to proper
contour
(not to remove proximal contact)

Advantages:
Fewer steps required
Much faster than indirect
technique

Disadvantages:
Chance of locking hardened
temporary material into small
undercuts
Marginal fit slightly inferior to
indirect technique
More difficult to contour it without
guidelines of postoperative cast

Trim away much of the border of
preoperative alginate impression to
facilitate seating

Flow mixed temporary material into
preoperative impression of
prepared tooth

Seat preoperative impression with
temporary material onto prepared
tooth

Formed temporary removed from
preparation ( c is contact area
which must not be removed during
trimming)

Thin excess material can be
removed with scissors

Internal surface of temporary has
record of cavosurface margin that is
used as a guide for final trimming

After final impression is made,
temporary is cemented with
temporary cement

Definition
It’s the temporary retraction
(pushing away) of the gingival
tissue from the tooth surface in
the cervical area , which lead to
widening of the gingival sulcus,
to give more clear observation
and operation in this area

Retraction
cord
Rotary
curettage
Electrosurg
ery
Copper
ring
Retraction can be achieved by

Retraction
Cord
• Single cord
technique
• Two cord
technique
Retraction
Cord
• Plain
• Chemical
solutions

0 Extra fine 1 Fine
2 Medium 3 Thick

A piece of fine retraction cord is
placed in the gingival sulcus

A thicker cord is placed over the
first leaving a tag for removal

The thicker cord is removed after
washing (note clearly defined sulcus)

The resulting impression of the
first premolar

Often results in inadequate gingival
retraction
Single cord
Two cord technique
Improves retraction

Result in bleeding on removal in > 50%
cases
Are twice as effective if first soaked
in solution
Plain Cord
Impregnated cords

Disadvantages:
Trauma and recession from
excessive packing pressure
Cord contaminated by gloves may
prevent impression of gingival
sulcus from setting
Florid inflammation if first cord not
removed

Epinephrine (1:1000conc.)
Alum (eg Aluminium potassium
sulphate)
Ferric sulphate (15.5%)
Chemical solutions used to soak
retraction cord

Similarly haemostatic, retractive
and both give minimal
postoperative inflammation
Alum and epinephrine
Ferric sulphate
Clinically better, but needs to be
rubbed firmly onto bleeding gingival
sulcus

Disadvantages:
Epinephrine syndrome ( raised
heart rate, respiratory rate and
blood pressure) when used on
lacerated gums in susceptible
patients

Ferric sulphate can stain the gums
yellow-brown for a few days
Alum in concentrated solution can
cause severe inflammation and
tissue necrosis (will concentrate if
top left off bottle)

Electrosurgery:
Controlled tissue destruction by
rapid heating from radio
frequency (>1 MHz) electrical
current placement in the mouth
Current passes from wire tip
(high current density) through
patient’s body into large area
collecting electrode (low current
density)

Contraindicated in patients with
cardiac pacemakers
To avoid tissue burns use plastic
mirrors and check integrity of tip
insulation
Don’t touch against metal
restorations
Keep collecting electrode away
from rings, buckles etc

Use of chamfered diamond bur
to remove epithelial tissue within
healthy sulcus to expose subgingival
finish line
Gingival sulcus depth must not
exceed 3mm and there should
be adequate keratinized gingiva
Rotary curettage (Gingettage):

A slight deepening of the sulcus
may result
Poor tactile sensation during
instrumentation gives high
potential for overextension and
damage
Disadvantages:

Copper ring:
Can serve as a means of carrying the
impression material as well as a
mechanism for displacing the gingiva
to insure that the gingival finish line is
captured in the impression
It has been used with impression
compound and elastomeric materials

The use of copper bands can
cause incision injuries of gingival
tissues, but recession following
their use is 0.3mm
These are especially useful for
situations in which several teeth
have been prepared
This is also known as matrix
method

Copper band
impression
Rubber Impression

The impression material should
have the following qualities
It must become elastic after
placement in the mouth
Must have adequate strength to
resist breaking or tearing on removal
Must have adequate dimensional
accuracy, stability, and reproduction
of detail

Must have handling and setting
characteristics that meet clinical
requirements
Must be free of toxic or irritating
components
Must be able to be disinfected
without distortion

Most common impression material
used for indirect casting technique
Polyvinyl siloxanes (addition
reaction silicones)

Advantages of polyvinyl siloxane
impression
Excellent reproduction of detail
Excellent dimensional stability
User friendly
No unpleasant taste or odor
Can be easily disinfected
without distortion

Dispense heavy body material
into tray, filling it to the height of
the tray

Place the 3-inch square of plastic
wrap over the tray and gently
smooth across impression material

Create a custom like tray by keeping
the plastic wrap in place and seating
the impression tray in the patient’s
mouth. once fully seated, move the tray
slightly front to back and side to side to
help create space for second PVS

Before heavy body completely sets
remove tray from the mouth. Using
fingers carefully smooth/pinch out
tooth detail. The goal is to create
space for light body wash

Load the light body material into
the now formed custom tray of
heavy body

Place tray into the patient’s mouth,
use the tab centered with the nose as
a guideline. Keep equal pressure on
the tray until the material is set

Inspect the impression for
quality and accuracy before
dismissing the patient

Aids in the creation of all types of
dental restorations
Eliminates the need for coating
teeth
Utilizes single-use imaging shields
for maximum infection control
Allows for subgingival preparations
Quick-only taking about 3-5minutes
to scan

No need for distasteful material that
cause some patients to gag
Reduced possibility of impression-
taking errors and elimination of
material inaccuracies
Can be stored electronically saves
space, efficient record keeping and
paper-free envoirnment

Tight proximal contacts
Due to imprecise die location or
abrasion of the adjacent stone
contact points
Corrected by
Identifying tight contacts by
interposing articulating paper,
grind and polish

Casting blebs on fit surface
Air bubbles trapped during
investment
Identify under magnification
and remove with small round
bur
Corrected by

Overextended margins
Poor impression, poor die
trimming, surplus untrimmed
wax
Remedy
Trim from axial surface and
polish-if not correct consider
return to lab

Under-extended margins
Poor impression, Poor die
trimming, Difficulty identifying
finish line
If under-extension obvious and
impression satisfactory cast
restoration should be remade.
Alternatively retake impression
Remedy

No die spacer(space needed
for cement lute)
Technician not aware of
technique or forgot to apply
Results in tightly fitting crown which
may not seat and may lift further
after cementation. Return to lab.
Remedy

Preparing the mouth:
Remove the temporary restoration
making sure that all temporary
cement dislodged from the
preparation walls & cleared away
Isolate region with cotton rolls

Use hand pressure to initially
seat casting on tooth by applying
ball burnisher in pit anatomy

Ensure complete seating using
masticatory pressure by having patient
close on Burlew Wheel

Inspect marginal fit of tried-in-casting

Initial occlusal contact is high &
produces heavy mark with metal-colored
center. Note corresponding perforation
in articulating paper.

Remove most incorrect portion of
contact, leaving most correct portion
intact

Proper occlusal contacts in MI are
composed of cusp tips placed against flat
or smoothly concave surfaces for
stability.
Incline contacts are less stable and tend
to deflect tooth.

Testing intensity of occlusal contacts
with thin Shim Stock used as a
“feeler gauge”

Removing undesirable contact that
may occur on working side during
lateral mandibular movement

Removing undesirable contact that
may occur on non-working side during
lateral mandibular movement

Burnisher is moved parallel with the
margin

Using discoid on margins inaccessible
to ball burnisher

Fine-grit carborundum stone may be
used to improve marginal adaptation

Fine-grit sandpaper disc to accessible
supragingival proximal margins

Gingival margin trimmer to remove
excess metal in areas inaceesible to
paper disc

Rubber point to smooth metal and tooth
of scratches left by carborundum stone

Tip of sharp black spoon is inserted in
occlusal embrasure with back of spoon
against adjacent marginal ridge

Spoon is then pivoted in the direction
of arrow using adjacent tooth as a
fulcrum removing casting for
cementation

• Provisional
cementation
Soft
Cements
• Definitive
Cementation
Hard
Cements
Cement Selection

Soft Cements
Temporary cements are used if a
restoration would have to be
removed as a result of sensitivity or
other symptoms, as well as for the
temporary cementation of
provisional coverage

Hard Cements
Permanent cement is used in the
long-term cementation of gold and
ceramic restorations such as
inlays/onlays, crowns, bridges,
veneers

Hard
Cements
Conventional
Zinc
Phosphate
Zinc poly
carboxylate
Glass
ionomer
Resin Based
Hybrid

Zinc phosphate cement
Long track record
Good compressive strength(if
correctly proportioned)
Good film thickness
Advantages:

Reasonable working time
Resistant to water dissolution
No adverse effect on pulp
although initially acidic

Disadvantages:
Low tensile strength
No chemical bonding
Not resistant to acid dissolution

Zinc Polycarboxylate Cements
Good compressive strength(if
correctly proportioned)
Adequate working time
Bonds to enamel and dentine
Advantages:

Resistance to water dissolution
is less good than zinc phosphate
No adverse effect on pulp and
less acidic than zinc phosphate

Disadvantages:
Can deform under loading
Can be difficult to obtain low
film thickness

Glass Ionomer Cements
As for polycarboxylate cement
Fluoride release
Advantages:

Disadvantages:
Sensitive to early moisture
contamination
Has been accused of causing
post-operative sensitivity but a
controlled trial reports it is no
worse than zinc phosphate

Resin Cements
Advantages:
Good compressive and tensile
strengths
Resistant to water dissolution
Relatively resistant to acid
dissolution

Disadvantages:
Film thickness varies substantially
between materials
Excess material extruded at
margin may be difficult to remove
especially proximally

Polymer degradation occurred
due to hydrolysis over time
Incomplete polymerization can
lead to irritation of the pulp by
unreacted monomers
Combination with dentin bonding
agent for superior properties but
not ideal because of postoperative
sensitivity

Resin Modified Glass Ionomer
(RMGI) Cements
Advantages:
Relatively easy to handle
Suitable for routine application

Disadvantages:
Adhesion to tooth structure is
not good
Excess water absorption
HEMA released from these
has damaging biological
properties

Hybrid-Acid-Based CaAl/Glass Ionomer
New dental luting agent
Water based hybrid composition
comprising calcium aluminate and
glass ionomer components that is
mixed with distilled water

Typical histological features of a pulp
after cementation with the cement. No
inflammation or other signs of irritation
were observed.

Applying cement with No. 2 beaver-
tail burnisher to preparation side of
onlay

Seating onlay with ball burnisher
and hand pressure

Placing Burlew disc over onlay

Cementing cast metal onlay on
preparation. Patient is instructed to
apply masticatory pressure

With a sweeping, rolling motion of
forefinger, clean any accesible facial
and lingual margin of excess cement

Remove excess set cement with explorer
and air-water spray. Use dental tape with
knot to dislodge small pieces of
interproximal cement

class II cast metal restorations

class II cast metal restorations

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