This topic very important during restoring tooth (ex. CL II), to prevent excess materials and provide good contact and smooth surface...
Also help during diagnosis of proximal carie...
2. INTRODUCTION
Teeth and periodontium are designed in such a manner that
mutually they significantly contribute to their own health and
support. They are complimentary to each other.
Proper form and alignment of teeth protect periodontium. During
mastication, the contours of teeth as a unit protect the
periodontium.
A breach in the continuity of contacts of teeth give rise to diseases of
periodontium resulting in loss of teeth.
3. Ideal tooth form of interproximal area
1. Interproximal embrasures extend on all the four sides of a tooth
with definite shape around each contact area. These four
embrasures are gingival, occlusal, lingual and facial.
2. Anterior teeth have less pronounced embrasures than posterior
teeth.
3. Interproximal space between the adjacent teeth is proper
triangular in shape with apex at the contact area and base towards
the outer surface. This triangle increasingly widens out in from the
contact area of all the four directions—occlusal, lingual, gingival and
facial.
4.
5. Consequences of not restoring proximal areas
• Food impaction leading
to recurrent caries.
• Change in occlusion and
intercuspal relations
• Rotation and drifting of
teeth
• Trauma to the
periodontium.
8. MATRICING
MATRICING: It is the procedure by which a temporary wall is built opposite to the axial wall,
surrounding the tooth structure which has been lost during the tooth preparation.
MATRIX: It is an instrument which is used to hold the restoration within the tooth while it is
setting.
Parts of Matrix:
1) Retainer (Matrix band retainer): It holds a band in desired position and shape.
2) Band (Matrix band): It is a piece of metal or polymeric material, intended to give support and
form to the restoration during its insertion and setting, Matrix band should extend 2 mm above
the marginal ridge height and 1 mm below gingival margin of the preparation.
9. Functions of a Matrix
1. To confine the restoration during setting.
2. To provide proper proximal contact and contour.
3. To provide optimal surface texture for restoration.
4. To prevent gingival overhangs.
10. Requirements of a Matrix Band
1. Rigidity: rigid enough so as to withstand the pressure of condensation &maintains its shape.
2. Adaptability.
3. Easy to use: it does not cause any difficulty to the patient, or hindrance to the operator during
restoration of the tooth.
4. It should be able to displace the gingiva and rubber dam for ease in working.
5. Nonreactive.
6. Height and contour: not extend more than 2 mm beyond the occlusogingival height of the crown
of tooth & helps in formation of a physiologic proximal contact relationship.
7. Application: it can be applied and removed easily.
8. Sterilization.
9. Inexpensive.
11. Classification of Matrices
Classification of Matrices
I. Based on mode
of retention
i. With
retainer, e.g.
Tofflemire
matrix.
ii. Without
retainer, e.g.
Automatrix.
II. Based on type
of band
i. Metallic
nontransparen
t matrixes.
ii. Nonmetallic
transparent
matrixes.
III. Based on type of cavity for which it is used
i. Matrix for class I
cavity preparation
– Double
banded
Tofflemire
(Barton
matrix).
ii. Matrixes for class II
cavity preparation
– Single banded
Tofflemire matrix,
Rigid material
supported
sectional matrix,
Ivory no. 1, Ivory
no. 8, Copper
band matrix,
Anatomical
matrix,
Automatrix.
iii. Matrixes for
Class III cavities
– Mylar strip
matrix.
– S-shaped
matrix.
iv. Matrixes for class
IV cavities
Custom lingual
matrix, Mylar
strip matrix,
Transparent
crown form
matrix,
Modified S-
shaped band
matrix.
v. Matrixes for class
V cavities
– Window
matrix.
– Cervical
matrix.
12. Ivory No. 1 Ivory No. 8 Tofflemire Universal Matrix Retainerless Automatrix System S-shaped
Matrix Band
Indication
For unilateral
class II (MO or
DO).
• Unilateral or bilateral
class II (MOD).
• Class II compound
tooth preparations
having more than two
missing walls.
• Class I with buccal or lingual
extensions.
• Unilateral or bilateral class II (MOD).
• Class II compound tooth
preparations having more than two
missing walls.
• In tilted and partially erupted teeth.
• In patients who cannot tolerate
retainers.
• For complex amalgam restorations.
•class III
restorations.
• class II slot
preparations.
Advantages
• Economical
• Can be
sterilized.
• Economical
• Can be sterilized.
• Economical.
• Can be sterilized.
• Can be used from both facial and
lingual sides.
• Sturdy and stable in nature.
• Provides good contact and contours.
• Can be easily removed.
• Simple to use.
• Convenient.
• Takes less time to apply.
• No interference from retainer, so
increased visibility.
Offers the
optimal
contour for
distal part of
canine and
premolar
Disadvantage
Cumbersome to
apply and
remove.
Cumbersome to apply
and remove.
• Cannot be used in badly broken
teeth.
• Does not offer optimal results with
resin restorations
• Unable to develop proper contours.
• Costly.
• Difficult to burnish because bands
are flat.
Cumbersome
to apply and
remove.
15. Tofflemire Universal Matrix Band Retainer
Designed by Dr BF Tofflemire.
Known as ‘universal’ matrix because it can be used in all types of
tooth preparations of posterior teeth.
The matrix band is fitted onto the retainer and then fitted loosely
over the tooth, which then can be tightened in position by means of
the screw.
16. Types of Tofflemire Matrix
Types
of
Tofflemire
Matrix
1. Based on type
of head
a. Straight
i. Head of matrix system is straight.
ii. Placed only from buccal side.
b. Contra-angle
i. Head is angulated.
ii. Placed either from buccal or lingual side.
2. Based on type
of dentition
a. Standard used in permanent dentition
b. Small used in primary dentition.
19. Types of Tofflemire bands
a. No. 1 Tofflemire band (universal
band).
b. No. 2 Tofflemire band (the MOD
bands): two extensions projecting at its
gingival edge to allow matrix application
in teeth with very deep gingival margins
in the proximal aspects of the tooth.
c. No. 3 Tofflemire band: used for MOD
cavities and has deeper gingival margins.
20. Retainerless Automatrix System
This matrix system can be adjusted
according to tooth shape and size.
The bands are available in different sizes,
and come in preformed and disposable
form.
The matrix is adapted over the tooth with
the clip on the buccal aspect. To tighten
the band, an automate mechanical device
is used.
Once the restoration is complete, the band
is cut with the help of cutting pliers.
23. TOOTH SEPARATION
The process of separating the involved teeth slightly away from each
other or bringing them closer to each other and/or changing their
spatial position in one or more dimensions.
24. Reason for Tooth Separation
Reason
for
Tooth
Separation 1. Examination
For initial proximal caries which is usually not seen on the
radiograph.
2. Preparation of teeth
For providing accessibility to proximal area during
preparation of CL II & CL III.
3. Polishing of restorations providing accessibility to the proximal area of CL II & CL III.
4. Matrix placement
Matrix can be placed easily during restoration of CL II
restoration.
5. Removal of foreign
bodies
Foreign bodies and objects, forced interproximally.
6. Repositioning shifted
teeth
It also helps to some extent in repositioning of shifted
teeth.
25. Methods of Tooth Separation
1. Slow or delayed separation:
◦ Separating rubber ring/bands.
◦ Rubber dam sheet.
◦ Ligature wire/copper wire.
◦ Gutta-percha stick.
◦ Oversized temporary crowns.
◦ Fixed orthodontic appliances.
2. Rapid or immediate
separation:
◦ Traction principle:
◦ a. Ferrier double bow separator.
◦ b. Non-interfering true separator.
◦ Wedge principle:
◦ A. Elliot separator.
◦ b. Wedges.
26. Methods of Tooth Separation
Methods of Tooth Separation
1. Slow or delayed separation
Separating
rubber ring/
bansss.
Rubber
dam
sheet.
Ligature
wire/copper
wire.
Gutta-
percha
stick.
Oversized
temporary
crowns.
Fixed
orthodontic
appliances.
2. Rapid or immediate
separation
Traction principle:
a. Ferrier
double
bow
separator
b. Non-
interfering
true
separator
Wedge principle:
A. Elliot
separator
b. Wedges
27. Wedges
Wedges are devices which are usually preferred for rapid tooth
separation. These are used in tooth preparation and restoration.
28. Functions of wedges
• Help in rapid separation of teeth.
• Prevent gingival overhang of restoration.
• Provide space to compensate for thickness of matrix band.
• Help in stabilization of retainer and matrix during restorative procedures.
• Provide close adaptability in cervical portions of the proximal restorations,
thereby help in achieving correct contour and shape at cervical area.
• Help in retracting and depressing the interproximal gingival area, thus help in
minimizing trauma to soft tissue.
• Help in depressing rubber dam in interproximal area.
30. Wooden wedges
• Most commonly used and preferred.
• Can be easily trimmed and can be fitted in gingival embrasure.
• Adapt well in the gingival embrasure.
• Easy to use.
• Wooden wedges absorb water, thus increase the interproximal
retention.
• Provide stabilization to matrix band.
• Available in 2 shapes {Triangular & Round}.
31. Wooden wedges
a. Triangular wedge
Most commonly used.
It has two positions—apex and the base:
• * Apex of the wedge usually lies in gingival
portion of the contact area.
• * Base lies in contact with gingiva. This helps
in stabilization and retraction of Gingiva.
Used in tooth preparations with deep gingival
margins.
b. Round wedge
Not so commonly used.
Made from wooden tooth picks by
trimming the apical portion.
It has uniform shape.
Used in class II tooth preparation.
33. Plastic wedges
Though commercially available, they are not much preferred
because:
• Trimming is difficult
• Adaptability is difficult in some cases.
a. Normal wedge: Similar to the wooden wedges in configuration
and usage.
b. Wave-shaped wedges.
35. Light-transmitting wedge
• As the name indicates this type of wedge transmits 90-95% of incident light.
• It is a type of plastic wedge.
• Transparent in nature.
• Designed for use in cervical area of class II composite resin restoration.
• Advantages of light-transmitting wedges over other wedges in composite
restorations:
◦ – Help in reducing the polymerization shrinkage as these transmit light.
◦ – Better adaptability.
37. Important points regarding wedges
1) Select the type and shape according to requirement.
Type of wedge Indications
Round wooden Conservative class II preparations
Triangular wooden Preparation with deep gingival margin
Plastic Preparation with deep gingival margin
Light transmitting Cervical portion of class II composite
38. Important points regarding wedges
2) Length of the wedge should be in the range of 1-1.2 cm.
3) It should not irritate tongue, cheek and gingival tissue.
4) Wedge should be inserted beneath the contact area in the gingival
embrasure.
5) Usually inserted from lingual embrasure area as it is wider than buccal area.
Sometimes when it irritates tongue; it can be inserted from buccal area also.
6) Wedge should be firm and stable during restorative procedure.
7) Should not be forcibly inserted in the contact area leading to pain and
swelling.
