Restorations that are used to replace any missing structure of teeth that have fractured, have severe caries involvement

Restorations that are used to replace
any missing structure of teeth that have fractured,
have severe caries involvement

1. COMPLEX
AMALGAM
RESTORATIONS
1
Presented by- Dr. ABDUL KADIR
Dept. Of Conservative dentistry and Endodontic

2. CONTENTS
INTRODUCTION
INDICATIONS
CONTRAINDICATIONS
ADVANTAGES
DISADVANTAGES
TYPES OF COMPLEX AMALGAM RESTORATIONS
1. CUSPAL-COVERAGE
2. PIN- RETAINED AMALGAM RESTORATIONS
3. AMALGAPINS
4. SLOT- RETAINED AMALGAM RESTORATI0NS
5. AMALGAM FOUNDATIONS
6. BONDED AMALGAM RESTORATIONS
STEPS IN RESTORATION
1. Matrix & Amalgam placement
2. Finishing the amalgam restoration
CONLUSION
REFERENCES
2

3. INTRODUCTION


3

4. The restoration of severely damaged but vital teeth with
amalgam requires procedures which enhance the
resistance & retention form, ranging from
 the placement of grooves or pinholes (Direct Anchorage)
 to the reconstruction of the tooth with a Pin-retained
crown (Indirect Anchorage).
This type of restoration is called an Extensive Amalgam
Restoration, defined as an Amalgam Restoration in which
one or more cusps are reconstructed, in combination with
any form of auxiliary retention.
4

5. Robbins & Summit 1988, Smales 1991 have named this type of
restoration as “Complex Amalgam Restoration.
Complex amalgam restorations are restorations used to replace
missing tooth structure of teeth that has been fractured or are
severely involved with caries or existing restorative material. These
restorations usually involve the replacement of one or more missing
cusps.
5

6.  According to Summit, Robbins, Hilton & Schwartz, 2006
the key to success of a complex amalgam restoration is
the cavity preparation designed to provide adequate
retentive and resistance form.
in a complex amalgam preparation since the walls or
portions of them are lost during the fracture.
 For such reason, it is necessary for the prep to have
certain features, such as
vertical walls,
grooves, troughs, slots and pins,
that would provide adequate resistance and retention to
the restoration.
6

7. USES
They may be used as
 Control Restorations in teeth that have a
questionable pulpal or periodontal prognosis,
 Control restorations in teeth with acute and
severe caries,
 Definitive final restorations or foundations.
7

8. INDICATIONS
In a tooth severely involved with or existing restorative material,
any undermined enamel or weak tooth structure subject to
fracture must be removed and restored.
A tooth with severe caries that may require endodontic
therapy or crown lengthening or that has an uncertain
periodontal prognosis often is treated initially with a control
restoration.
As interim restorations for teeth that require elaborate occlusal
alterations ranging from vertical dimension changes to
correcting occlusal plane discrepancies.
Economics- When cost of indirect restorations is a major factor
for the patient it may be an appropriate treatment option.
Age & Health of patient- In geriatric and debilitated patients.
8

9. CONTRAINDICATIONS
Patient with significant occlusal problems
If the area is esthetically important for the patient
If the tooth cannot be restored because of anatomic and/ or
functional considerations
9

10. ADVANTAGES
Conserves Tooth Structure– preparation for complex amalgam
restoration is more conservative than for an indirect restoration.
 Appointment time – Restoration can be completed in single
appointment.
Resistance & Retention forms: Are increased by the use of pins & slots.
Economics – Inexpensive as compared to cast restoration.
10

11. DISADVANTAGES
Dentinal micro fractures – Drilling pin holes and placing
pins can cause micro fractures in dentin and
development of internal stresses in dentin.
Micro leakage – Amalgam restorations using cavity
varnish exhibit micro leakage around all types of pins.
Decreased strength of amalgam – Tensile strength &
horizontal strength of pin retained amalgam restorations
are significantly decreased.
Penetration & Perforation –Pin retention increases the risk
of penetrating into the pulp or perforating external tooth
surface.
Tooth Anatomy- Proper contours & occlusal contacts&
anatomy are sometimes difficulty to achieve with large
complex restorations.
11

12. TYPES OF COMPLEX
AMALGAM
RESTORATIONS
12

13. TYPES OF COMPLEX AMALGAM
RESTORATIONS
1. CUSPAL-COVERAGE
2. PIN- RETAINED AMALGAM
RESTORATIONS
3. AMALGAPINS
4. SLOT- RETAINED AMALGAM
RESTORATI0NS
5. AMALGAM FOUNDATIONS
6. BONDED AMALGAM
RESTORATIONS
13

14. CUSPAL COVERAGE
14

15. CUSPS CAPPING
When caries is extensive, reduction of one or more of
the cusps for capping may be indicated.
When the facial or lingual extension exceeds two
thirds the distance from a primary groove toward the
cusp tip (or when the facial-lingual extension of the
occlusal preparation exceeds two thirds the distance
between the facial and lingual cusp tips), reduction
of the cusp(s) for amalgam is indicated.
15

16. TOOTH PREPARATION
If the cusp(s) to be capped is located
at the correct occlusal height from
preparation, depth cuts should be
made on the remaining occlusal
surface of each cusp to be capped.
Make depth gauge cuts of 2mm for
functional cusps and 1.5mm minimum
for nonfunctional cusps on each cusp
to be capped.
Uniform reduction is ensured using the
depth gauge cuts as a guide.
Rounden any sharp external corners at
the junction of the cusp-reduced
surface to decrease stress
concentration in the capping
amalgam and so improving the
resistance to occlusal forces.
16

17. When reducing only one or two facial or
lingual cusps, the cusp reduction should be
extended just past the facial or lingual
groove, creating a vertical wall against the
adjacent unreduced cusp.
When possible, opposing vertical walls
should be formed to converge occlusally,
to enhance primary retention form.
Pulpal and gingival walls should be flat and
perpendicular to the long axis of the tooth.
For auxillary resistance and retention pins,
slots or coves can be prepared.
Coves are prepared in horizontal plane
and locks are prepared in a vertical plane.
Slots may be prepared along the gingival
floor, axial to the DEJ instead of, or in
addition to, pin-holes.
17

18. PIN-RETAINED
AMALGAM
RESTORATIO
NS
18

19. PIN RETAINED AMALGAM
RESTORATIONS
DEFINITION:-
A Pin retained restoration may be defined as any restoration
requiring the placement of one or more pins in the dentin to
provide adequate retention form.
19

20. INDICATIONS
For restoration of mutilated and badly broken
down teeth especially in young patients
where the gingival lines are still high, where
massive tooth preparations necessitated by
cast restorations are contraindicated.
Badly broken down teeth, prior to
endodontic or orthodontic treatment, pin
retained restorations are placed as a
transitional restoration to act as a build up for
rubber dam application or band
attachment.
20

21. As a foundation for partial or full veneer
cast restoration or metal ceramic
restorations, thereby saving considerable
amount of tooth structure by eliminating
the need to remove undercuts.
As a provisional restoration in teeth with
questionable prognosis endodontically or
periodontally, until a definitive prognosis is
established.
In preparations where adequate retention
form cannot be established with slots, locks
or undercuts, pins are used as a means of
providing auxiliary retention.
21

22. ADVANTAGES
Conservation of tooth structure – pin hole preparation is more
conservative than slot preparation.
Appointment time – Restoration can be completed in single
appointment.
Economics – Inexpensive as compared to cast restoration.
22

23. DISADVANTAGES
Dentinal micro fractures – Drilling pin holes and placing pins can
cause micro fractures in dentin and development of internal stresses
in dentin. This is significant when minimal dentin is present.
Micro leakage – This can occur in pin – restoration interface.
Decreased strength of amalgam – Compressive strength of amalgam
is not affected whereas tensile and transverse strength are
decreased.
Perforation – Risk of perforation into pulp or external tooth surface.
23

24. TYPES OF PINS
Cemented pins:
It was introduced in 1958 by Dr.
Miles Markley. In this type, the
pin channel diameter is 0.025
to 0.05mm larger than the
diameter of the pin.
It comes in two sizes
Pin Channel Diameter Pin
Diameter
0.027 0.025
0.021 0.020
24

25. Friction lock pins:Friction lock pins:
Goldstein in 1966 introduced Goldstein in 1966 introduced
the friction locked pin the friction locked pin
technique. technique.
In this type, the pin channel In this type, the pin channel
diameter is 0.025 mm narrower diameter is 0.025 mm narrower
than the pin diameter. than the pin diameter.
These pins are 2-3 times more These pins are 2-3 times more
retentive than cemented pins.retentive than cemented pins.
It comes in one size It comes in one size
Pin Channel Diameter is 0.021 Pin Channel Diameter is 0.021
and Pin Diameter is 0.022.and Pin Diameter is 0.022.
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26. Self-threading pins:
It was introduced by Going in 1966.
The pin channel diameter is 0.038 to
0.05 mm narrower than that of the
pin.
The pin is retained by threads
engaging the dentin as it is inserted.
The elasticity (resiliency) of the
dentin allows insertion of a threaded
pin into a hole of smaller diameter.
It is 3-6 times more retentive than
cemented pins.
Lateral and apical stresses can be
generated in dentin when a self
threading pin is inserted.
26

27. Several styles of self threading pins are available. The
Thread Mate System (TMS) is the most widely used self
threading pin because of its
Versatility
Wide range of pin sizes
Color – coding system
Greater retentiveness
Gold-plated pins, which may eliminate the possibility of
corrosion.
27

28. The TMS pins are available in four sizes
depending on the diameter of the pin
namely
1. Regular – 0.78 mm 3. Minikin – 0.48 mm

2. Minim - 0.61 mm 4. Minuta – 0.38 mm
28

29. For each of the four sizes,
several designs are available
namely
1. Standard design:
These pins are 7 mm in length
and should be shortened after
seating in the pin channel.
2.Self-shearing design:
These pins automatically shears
off at 4mm from the dentinal
end, when this end comes in
contact with the pin channel
floor.

29

30. 3.Twin stage or Two in one design:
In this type two pins are joined together end to end but
separated by a shear line. The wrench attachment
part is on one end only. After threading the
peripheral stage (peripheral pin), it will separate
from the wrench attachment stage as soon as it
contacts the pin channel floor. Another pin
complete with its wrench attachment will remain, to
be used in another pin channel.
4. Disposable latch head design:
-This type pins have a plastic head to fit a geared
down slow speed contra-angle hand piece. The
Link Series and Link Plus pins come under this design.
30

31. The Link Series pin is contained in a
color coded plastic sleeve that fits in
a latch type contra-angle hand
piece. The pin is somewhat free
floating in the plastic sleeve to allow it
to align itself as it is threaded into the
pin hole. When the pin reaches the
bottom of the hole, the top portion of
the pin shears off, leaving a length of
pin extending from the dentin. The
plastic sleeve is then discarded.
The Link Plus pins are self-shearing and
are available as a single or two in one
pin contained in a color-coded
plastic sleeve. This design has a
sharper thread, a shoulder stop at 2
mm and a tapered tip to more readily
fit the bottom of the pin hole as
prepared by the twist drill. It also
provides a 2.7mm length of pin to
extend out of the dentin.
31

32. FACTORS AFFECTING THE RETENTION
OF THE PIN IN DENTIN AND AMALGAM
Type of pin:
In order of retentiveness, self-threading pin is
most retentive, friction lock pin is intermediate
and cemented pin is the least retentive.
Surface characteristics:
Retention of the pin in amalgam is influenced by
the number and depth of elevations in the pin.
Therefore, self-threading pins are most retentive.
Orientation of the pins:
Retention of the pins is increased by placing
them in a non-parallel manner.
32

33. Number of pins:
Within limits, increasing the number of pins increases the
retention in dentin and amalgam.
Pins placed closer than 2 mm in dentin to each other in
one tooth will result in
--Crazing of dentin and increased potential for fracture.
--Decrease in the amount of available dentin between
the pins.
--Strength of amalgam restoration decreases.
Diameter of the pins:
Within limits, as the diameter of the pin increases the
retention in dentin and amalgam increases.
Extension into dentin and amalgam:
Pin extension into dentin and amalgam greater than 2
mm is unnecessary for pin retention and contraindicated
to preserve the strength of the dentin and amalgam.
33

34. FACTORS AFFECTING PLACEMENT OF
PINS IN PIN-RETAINED AMALGAM
RESTORATIONS
Pin size:
Two determining factors for selecting the
appropriate size of the pin are:
1. The amount of dentin available to safely
receive the pin
2. Amount of retention desired.
There is a gradual increase in pin retention to
restorative material with increasing pin diameter
up to 0.035 inch. Any diameter larger than this
will have no significant increase in retention.
34

35. NUMBER OF PINS
Factors to be considered regarding the number
of pins required are :-
Amount of missing tooth structure
Amount of dentin available to receive pins safely
Amount of retention required
Size of the pins
As a rule one pin per missing axial line angle
should be used.
When only 2-3 mm of the occluso-gingival height
of a cusp has been removed, no pin is required
because enough tooth structure remains to
prepare conventional retention.
35

36. Location of pin holes:
Several factors aid in locating pin holes.
Knowledge of normal pulp anatomy and external tooth
contours.
A current radiograph of the tooth.
Periodontal probe
Patient’s age.
36

37. Ideal conditions for pin hole location
Pin holes should be located half
way between the pulp and the DEJ
or external surface of the tooth root.
There should be at least 1 mm of
sound dentin around the
circumference of the pin hole which
assures proper distribution of
occlusal forces.
Pin placement allowing at least 1
mm of remaining dentin thickness
elicits minimal pulpal inflammatory
response.
37

38. Practical philosophies for pin hole location
The pin hole should be positioned no closer than
1 mm to the DEJ and no closer than 1.5 mm to
the external surface of the tooth.
Pin holes should be located on a flat surface
that is perpendicular to the proposed direction
of the pin hole.
Whenever 3 or more pin holes are placed, they
should be located at different levels of the tooth
so that stress resulting from pin placement in the
same transverse plane of the tooth is prevented.
When two or more pins are placed, the inter pin
distance should not be less than 2 mm. Inter pin
distances less than this will cause a definite
reduction in pin retention with the restorative
material.
38

39. Anatomical features that may preclude safe pin hole
placement should be considered.
 External perforation may result in pin hole placement
over the
-Prominent mesial concavity of maxillary first premolar
-At the mid-lingual and mid-facial bifurcations of the
mandibular first and second molars.
-At the mid-facial, mid-mesial and mid-distal furcations of
maxillary first and second molars.

39

40. PIN HOLE PREPARATION
When the pin hole location has been determined, with
a No.1/4 bur, a pilot hole is prepared approximately one
half the diameter of the bur at each location.
The Kodex drill or twist drill is used for drilling pin holes.
Two types of Kodex twist drill --Standard & Depth limiting.
It is made of high-speed tool steel that is swaged into an
aluminum shank.
The aluminum shank acts as a heat absorber.
It is color coded to easily match with sizes.
40

41. It is an end cutting , revolving instrument with two blades, bibevelled
in longitudinal section at precisely the same distance from the tool’s
center.
The sides of the drill are helix shaped allowing the escape of debris
during end cutting.
The depth can be measured using a Omni-Depth Gauge.
Five rules when using Twist drill:
1. It should be used at low speeds of 300-500RPM.
2. The drill should be sharp
3. It should be used in direct cutting acts, with forces applied to the long
axis of the drill
4. The drill should be revolving while inside the pin channel.
5. Do not use pumping strokes, as it will widen the pin channel.
41

42. Angulation Of The Drill:
 With the drill in the hand piece,
the drill is placed in the gingival
crevice opposite the location for
the pin hole and positioned until
it lies flat against the external
surface of the tooth and then
without changing the
angulation obtained from the
crevice position, the hand piece
is moved occlusally and drill is
placed in the previously
prepared pilot hole.
With the hand piece rotating at
a very low speed (300 -500 rpm),
pressure is applied to the drill
and pin hole is prepared in one
or two movements until depth
limiting portion of the drill is
reached.
42

43. TECHNIQUES FOR PIN
INSERTION
CEMENTED PIN:
After the pin channel is prepared a
piece of wire is cut to the
designated length and tried in the
pin channel for proper fitting and
protrusion in the restoration.
After try in, a groove is established
at the desired length (shear line)
and the rest of the wire is used as a
handle to seat the pin.
The rest of the wire can be
separated from the pin after the
cementation by simply bending it.
43

44. FRICTION LOCK PIN
After the pin channel preparation, a countersink is
prepared at the pin orifice to a depth of 0.5 mm
using a 168 bur.
The correct length of the pin is then cut and the
ends of the pins are smoothed.
A mark is placed on the pin with a colored marker
to show the exact depth of the pin channel
preparation.
The pin is then seated at the pin channel orifice; a
specially made seater with a concave head is firmly
applied on the pin head with its axis parallel to the
pin.
With a hammer light strokes are applied to the
seater, parallel to its longitudinal axis until the
established mark on the pin comes to the cavity
floor.
44

45. SELF-THREADING PINS
There are four instruments that can be used :
1. TMS hand wrench
2. The Cable Pin setter (Loma Linda)
3. TMS auto clutch drive hand piece
4. Conventional latch type contra angle hand piece
The latch type hand piece is recommended for the
Link series & Link- plus pins. The hand piece is
activated until the plastic sleeve shears from the pin.
Then remove the sleeve and discard it.
45

46. A standard design pin is
placed in the
appropriate Wrench
and slowly threaded
into the pinhole until a
definite resistance is felt
when the pin reaches
the bottom of the hole.
 The pin should be then
rotated ¼ or ½ turn
counter clock-wise to
reduce dentinal stress
created by the end of
the pin pressing the
dentin.
 After which the Wrench
is removed carefully.
46

47. CUTTING OF PINS:
To cut excess pin, a No.1/4 or ½ size or No.169L bur at
high speed is oriented perpendicular to the pin.
If otherwise the rotation of the bur can unwind and
loosen the pin.
During cutting a steady stream of air is to be oriented
towards the pin.
The pin should be stabilized with a cotton pliers or a
hemostat.
47

48. BENDING PINS:
The bending of pin is done to provide adequate bulk of
amalgam between the pin and the external surface of the final
restoration.
Occlusal bending of the pin is necessary to allow condensation
of amalgam occluso-gingivally.
A TMS bending tool is used to bend the pin.
Place the bending tool on the pin where it is to be bent, and
with firm controlled pressure, rotate the bending tool until the
desired amount of bent is achieved.
When a pin is bent using a bending tool the fulcrum is at some
point along the exposed part of the pin.
48

49. FAILURE OF PIN RETAINED
RESTORATIONS:
The failure of pin-retained
restorations might occur at any of
five different locations. Failure can
occur
Within the restoration (restoration
fracture)
At the interface between the pin
and the restorative material (Pin
restoration separation)
Within the pin (Pin fracture)
At the interface between the pin
and the dentin (pin – dentin
separation)
Within the dentin (Dentin fracture)
 Failure is more likely to occur at the
pin-dentin interface than at the pin-
restoration interface.
49

50. Broken drills and broken pins:
Twist drills may break if it is stressed laterally or
allowed to stop rotating before being removed from
the pin hole.
Standard pin might break if turned more than
needed to reach the bottom of the pin hole.
Pins may also break if care is not exercised during
bending.

Loose pins
Self-threading pins sometimes do not properly
engage the dentin because the pin hole was
inadvertently prepared, too large or a self-shearing
pin failed to shear resulting in stripped out dentin.
A properly placed pin can be loosened while being
shortened with a bur, if the bur is not held
perpendicularly to the pin and stabilized.
50

51. AMALGAPIN
51

52. AMALGAPIN
Shavell in 1980 introduced this
technique for complex
amalgam restoration.
Retention for amalgam is
provided by preparing dentin
chambers with No.245 bur
parallel to the external surface of
the tooth to a depth of 2 to
3mm.
A tapered fissure bur can also be
used.
Study by Leach et al showed
that shear strength of amalgapin
is significantly less than amalgam
with threaded pins.
52

53. SLOT-
RETAINED
AMALGAM
RESTORATIO
NS
53

54. SLOT-RETAINED AMALGAM RESTORATIONS
A slot is a retention groove in dentin
whose length is in a horizontal plane.
Slot retention may be used in conjunction
with pin retention or as an alternative to
it.
Slot retention are used in preparations
with vertical walls that allow retention
locks to oppose one another.
Slots are particularly indicated in short
clinical crowns and in cusps that have
been reduced 2 to 3mm for amalgam.
Slots are less likely to create micro
fractures in the dentin and to perforate
the tooth or penetrate the pulp.
54

55. TOOTH PREPARATION
Slot length depends on the extent of the
tooth preparation.
Slots are usually placed on the facial,
lingual, mesial and distal aspects of the
preparation.
The slot may be segmented or
continuous, depending on the amount of
missing tooth structure.
Using a No.331/2 bur a slot is placed in
the gingival floor 0.5mm axial of the DEJ.
The slot is atleast 0.5mm in depth and
1mm or more in in length depending on
the distance between the vertical walls.
An alternative technique in which 169L
bur is used initially and then No. 331/2 bur
is used for convergence .
55

56. AMALGAM
FOUNDATIONS
56

57. AMALGAM FOUNDATIONS
A foundation is an initial restoration of a severely
involved tooth. The tooth is restored so that the
restorative material will serve in lieu of tooth
structure to provide retention and resistance
forms during the development of the subsequent
final cast restoration.
57

58. Tooth preparation technique depends on the
type of retention needed:-
1. PIN RETENTION
2. SLOT RETENTION
3. CHAMBER RETENTION (In case of
endodontically treated teeth)
58

59. PIN RETENTION
Severely broken down with few or no vertical walls,
where an indirect restoration is indicated, may
require a pin-retained foundations.
Difference between the use of pins for foundations
and in definitive restorations is the distance of pin
holes from external surface of the tooth.
For foundations:-
1.The pin holes must be farther from the external
surface of the tooth (farther internally from DEJ).
2.More bending of pins may be necessary to allow for
adequate axial reduction of the foundation without
exposing the pins during cast metal tooth
preparation.

59

60. Location of the pin hole from the external
surface of the tooth foundations depends on:-
1. Occlusogingival location of the pin (External
morphology of pin).
2. Type of restoration to be placed (A
porcelain-fused-to-metal or all-ceramic
preparation requires more reduction than a full
gold crown).
3. Type of margin to be prepared.
 Preparation with heavily chamfered margins at
a normal occlusogingival location require pin
placement at a greater axial depth.
60

61. SLOT RETENTION
Slots are placed in the gingival floor of a preparation with a No.33 ½
bur.
Foundation slots, as with pins, are placed slightly more axial (farther
inside the DEJ) than indicated for conventional foundations.
Number of remaining vertical walls determines the indication for slots.
Slots are used to oppose retention locks in vertical walls or to provide
retention where no vertical walls remain.
61

62. Retention locks are placed
in remaining vertical walls
with a No.169L or ¼ bur.
Slots are generally 0.5mm to
1mm in depth and the
width of the No.331/2 bur.
Length is usually 2 to 4mm,
depending on the distance
between the remaining
vertical walls.
62

63. CHAMBER RETENTION
Nayyar et al has described this technique for developing
foundations in multirooted endodontically treated teeth. It is
recommended only when:-
1. Dimension to the pulp chamber is adequate to provide
retention and bulk of amalgam.
2. Dentin thickness in the region of pulp chamber is adequate
to provide rigidity and strength to the tooth.
63

64.  Kane et al demonstrated that the
extensions into the root canal space 2 to
4mm is recommended when pulp
chamber height is 2mm or less.
Retention form is provided by natural
undercuts in the pulp chamber and
divergent canals.
Resistance form is provided by ginigival
extension of crown preparation 2mm
beyond the foundation onto sound tooth
structure.
64

65. BONDED AMALGAM
RESTORATIONS
65

66. BONDED AMALGAM RESTORATIONS
Bonded amalgam restorations are
restorations, which adhere to the
underlying tooth structure through a
resin mediated inter locking.
The use of adhesive resins helps in
improving the retention, resistance,
and the marginal seal of the amalgam
restorations.
The amalgam bonding systems require
dual characteristics to achieve optimal
wetting, as amalgam is strongly
hydrophobic, whereas enamel and
dentin are hydrophilic.
So, typical dentin bonding systems
have a wetting agent of which 4-
methyloxy ethyl trimellitic anhyride(4-
META) is frequently used.
Adhesives used for amalgam must be
self-curing or dual-curing one.
66

67. INDICATIONS
In situations that warrant auxillary retention, reinforcement of
remaining tooth structure, conservative preparations and
improvement of marginal seal.
Economics/Time factor.
Low gingivo-occlusal height of the teeth.
ADVANTAGES

A treatment option for extensively carious teeth where
economics plays a part.
Use of amalgam in low gingivo-occlusal height.
It permits a more conservative tooth preparation.
It reduces marginal leakage.
Reinforces tooth structure weakened by caries and tooth
preparation.
Reduces postoperative sensitivity after an amalgam
restorations.
67

68. LIMITATIONS & DISADVANTAGES
It increases the time taken to perform and may be
technique sensitive. It is a multi-stepped procedure.
Increases the cost of amalgam restorations.
During amalgam condensation resin is displaced on to
the adjacent tooth surfaces and produce radiological
artifacts at the gingival floor of the proximal box, which
could cause errors (recurrent caries).
It has not been in use long enough to allow a proper
evaluation of its clinical performance.

68

69. PROCEDURE:
Before the placement of matrix band,
the preparation side of the matrix band
should be lubricated so that adhesive
does not adhere to it after curing.
First, etchant is applied for 15 to 20 sec
to enamel and dentin simultaneously
and rinsed from the preparation.
The preparation is dried resulting in a
“glistening” appearance of the
surface.
After that the primer is applied to
desensitize the dentin, after which a
glossy appearance is seen.
Then the adhesive is applied, before
that amalgam should be triturated and
ready to be inserted in the preparation.
Immediate condensation of amalgam
facilitates intermingling of amalgam
and unset resin before it sets.
69

70. BONDING INTERFACE
The tooth restoration
interface is composed of
the tooth, intervening resin
and amalgam.
The tooth resin bond
includes tag formation,
formation of
micromechanical locking,
In addiction the use of 10-
Methacryloxy decyl
dihydrogen
phosphate(10-MDP) the
phosphate monomer
interacts with Tin and
copper in amalgam to
provide a chemical
adhesion.
70

71. STEPS IN
RESTORATIO
N
71

72. Matrix & Amalgam Placement
The primary function of the matrix is to restore
anatomic contours and contact areas.
Confine the amalgam so that adequate
condensation forces can be applied.
Restrict extrusion of amalgam to avoid overhang.
Impart an acceptable surface, especially in the area
of contact that cannot be carved and burnished.
Matrix for the complex amalgam should provide the
shape of the missing cusps that will be formed by the
amalgam.
72

73. Tofflemire retainers use matrix material , which is not
sufficient to provide height needed so a piece of matrix
material is added to the inside of the matrix to provide
additional cusp height.
When significant amount of tooth structure is missing, the
matrix will have a opening next to the prepared surface.
Amalgam is condensed into the space and must be
removed after the matrix removal.
For proper positioning of the cut pieces of matrix band
they can be spot welded.
Spot welded matrices should be stabilized and shaped
using modeling compound. The amalgam is then
condensed against the matrix which is held by a wooden
wedge.
73

74. Modeling compound supported matrices will
stabilize and maintain the matrix shape. After the
placement of matrix, wedge and contouring the
compound is heated over aflame and softened
compound is compressed against the matrix
with a wet gloved finger. The compound
supported matrix can be shaped into the
desired form.
74

75. Copper-band matrices
can be used for providing
contour and shape for
achieving the additional
height if required.
The bands are thick so in
the areas that will form
the proximal contacts
must be thinned using a
sandpaper disk. due to its
thickness they can be
used intact only on teeth
in which both mesial and
distal contacts are to be
restored.
75

76. Finishing the amalgam restoration
After the amalgam is condensed , the matrix is removed, the
restoration is carved first in the interproximal areas and then on
the occlusal.
The shape of the restoration is produced, the occlusal anatomy
is formed and rubber dam is removed
The objectives of polishing the amalgam restoration are:
-- Refinement of the margin
-- Development of the contour
-- Smoothening of the surface
The resultant amorphous polished layer will be less susceptible to
corrosion more esthetic and comfortable, and no more liable to
collection of plaque and debris than the adjacent tooth
surface.
The polishing procedure retards tooth discoloration, minimizes
marginal breakdown and adds many years of service to the
amalgam restoration.
76

77. CONCLUSION
Complex amalgam restorations are
restorations being less frequently used
due to the advent of other restorative
materials and techniques.
Due to the increasing benefits of these
materials and techniques there are
different types of auxiliary retention
forms and different variations of tooth
preparations that requires the
operator to be familiarized with the
various techniques, that can be used
on a regular basis.
77

78. REFERENCES
THE ART AND SCIENCE OF OPERATIVE DENTISTRY– STURDEVANT 5
TH

Edition
OPERATIVE DENTISTRY— MARZOUK
OPERATIVE DENTISTRY– SCHWARTZ
PRINCIPLES AND PRACTICES OF OPERATIVE DENTISTRY– CHARBENEAU
TEXTBOOK OF OPERATIVE DENTISTRY– BAUM, PHILLIPS & LUND 3
RD

EDITION
SCIENCE OF DENTAL MATERIALS—ANUSAVICE 11
th
EDITION
78

79. DCNA– RESTORATIVE DENTISTRY APRIL 2002
JOURNAL OF PROSTHETIC DENTISTRY– MAY 1980 VOL.43 NO.5
JOURNAL OF DENTAL RESEARCH- 1998, 77 ; 453
 JOURNAL OF DENTAL EDUCATION- 0CTOBER 2007.
79

80. 80
THANK YOU
.