Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Dental Matrices

Piece of metal or non-metal which is used to support and give form to the restoration during its packing

and hardening.

Matricing is the Procedure whereby a temporary wall is created opposite to axial walls, surrounding area

of tooth structure that were lost during preparation

Importance of

matrices

1. Serve as a temporary wall during condensation of any restorative material.

2. Give shape and contour to the restoration and prevent marginal overhangs.

3. Maintain the form of the restoration until hardening.

4. Keep the gingival tissues and rubber dam away from the cavity margins during the whole

procedures.

Requirements

1. Easy to adapt to the teeth.

2. Easy to contour

3. Easy to introduce and remove.

4. Smooth and highly polished.

5. Rigid enough to resist condensation pressure.

6. Compatible with the restorative material.

7. Thin enough to not interfere with the tightness of contact.

Types

Classification

Based on mode of retention

1. With retainer, e.g. Tofflemire matrix

2. Without retainer, e.g. Automatrix

Based on type of band

1. Metallic non-transparent matrixes

2. Non-metalic transparent matrixes

Based on type of cavity for which it is used

1.Matrix for class I cavity preparation Double banded Tofflemire (Barton matrix) 2.Matrices for class II cavity preparation

Single banded Tofflemire matrix

Rigid material supported sectional matrix

Ivory matrix no. 1

Ivory matrix no.8

Copper band matrix

Anatomical matrix

Automatrix

3. Matrices for Class III cavities

Mylar strip matrix

S-shaped matrix

4. Matrices for class IV cavities

Custom lingual matrix

Mylar strip matrix

Transparent crown form matrix

Modified S-shaped band matrix

5. Matrices for class V cavities

Window matrix

Cervical matrix

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Metallic Matrices

Circumferential Sectional

1. Tofflemire (universal)

2. Automatrix

3. Siquveland

4. T-band

1. Palodent

2. Composi –tight

3. Ivory

4. Strip-T matrix

Ivory Matrix Holder No.1

Provide one proximal wall.

Used in compound class II cavity preparation.

Ivory Matrix Holder No.8

Consists of a band that encircles the entire crown

Used for compound and complex cavity preparation

Universal (Tofflemire) Matrix

Indicated for compound or complex class II restoration.

Provide good stability, anatomic adaptation and ease of insertion and removal.

The Tofflemire matrix assembly consists of the following:

1. Matrix bands

2. Matrix retainer

3. Wedge

Retainer Components Matrix Bands

Made of flexible stainless steel

Available in different thicknesses: 0.001, 0.0015 and

0.002 inch

Available in various occluso-gingival widths.

Pre-contoured bands, dead-soft bands and coated bands

are also available.

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Burnishing Matrix Band

1. With band on pad, use small burnisher to deform band.

2. Use large burnisher to smooth band contour.

3. Burnished matrix band used for MOD tooth preparation

Rules of application

1. When the matrix band is folded, the loop will have two circumferences:

The larger circumference of the band is the occlusal edge and is always placed toward the occlusal surface.

The smaller circumference of the band is the gingival edge and it is always placed toward the gingiva.

The matrix band placed in the slotted side of the retainer is placed gingivally.

The straight retainer placed on the buccal side.

The loop of the band could be placed:

1. Centralized 2. From right 3. From left

Depending on the location of the tooth so that the retainer be parallel to buccal surfaces of teeth and not disturbed by

cheek movement.

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Double matrix technique

Indicated when using tofflemire matrix for compound class I (OP / OB)

A piece of stainless matrix material is cut and fitted between the tooth surface and the band a compound coated wedge

is inserted in between and adapted by a burnisher

To provide well-adapted matrix bucally and palataly

Omni-matrix Is a pre-assembled disposable tofflermire retainer and band

Automatrix

It is a retainer-less matrix

It is ready-made bands formed into a circle and are available in three widths

Each band has a coil like autolock loop

A tightening wrench is inserted into the coil and turned clockwise to tighten the band

When finished the tightening wrench is inserted into the coil and turned counterclockwise to lossen the band

Removing pliers are used to cut the band

It is convenient saves time and improves visibility

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Copper band matrix

Assorted sizes make excellent matrices

Cylindrical shape

Bands are heated to redness in flame and quenched alcohol

With contouring pliers band is contoured

Festooned with scissors so gingival periphery of it corresponds to gingival curvature and CEJ

To stabilize wedges are placed

Indications Advantages Disadvantages

1. Badly broken tooth

2. Class II with large buccal or lingual

extension

Provide excellent contour Time consuming

Non-patented matrices The Wedged Matrix The Compound Wedged Matrix

Piece of well-contoured band material is cut to slightly

extend past the cavity margins buccally and lingually

and then stabilized in place by means of wooden

wedge.

The same as with the wedged type, but with further

stabilization using modeling compound.

Window Matrix

Universal matrix with the band having custom made trapezoidal hole related to the position of class V as it is

suitable for wide class V cavities with amalgam restoration.

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Dental Wedges (Rapid Tooth Separation Method)

Devices that stabilize the matrix band in place during condensation and hardening of the restorative material

Role of wedge

1. Hold the matrix band firmly in position cervically.

2. Prevent marginal overhangs

3. Maintain adequate teeth separation to compensate for the thickness of the matrix to provide tight contact.

Types of wedges

Wooden Wedge Plastic Wedge

Made of orange wood, absorbs saliva and increases in size.

Provide more stabilization to the matrix band with adequate temporary

separation of adjacent teeth.

Could be rounded, triangular, or anatomical.

Color-coded

Available in different sizes.

Wooden wedges better than plastic as it absorb water and increase in size

which potentiate its function.

Anatomical (triangular wedges) are recommended for deeper and / or wider

proximal preparations.

Rounded wedges are recommended for shallower and / or narrower

proximal preparations.

Similar to wooden wedge but made

of plastic.

Color-coded.

Placement of wedges:

1. Length of the wedge should be in the range of 1-1.2 cm.

2. It should not irritate tongue, cheek and gingival tissue.

3. Wedge should be inserted beneath the contact area in the gingival embrasure

4. Usually inserted from lingual embrasure area as it is wider than buccal area.

Operative II Lecture ( 8 ) Dr Ashraf Dr SaGeD Triangular VS Round wedge

Round Wedge of choice in conservative class II, however its wedging action is more Occlusal

Triangular

1. Preparation with deep gingival margin

2. With tofflemire MOD matrix band

3. Deep gingival margin

Modified Triangular

wedge (anatomic wedge)

Modified to conform to the approximating tooth contours

Prevents distortion of matrix contour

Preferred for deeply extended gingival margins

Modified Wedging Techniques

Double Wedging Wedge Wedging Piggyback wedging 2 wedges are used: one is inserted from

buccal embrasure and another is inserted

from lingual embrasure.

Indicated in Spacing between adjacent

teeth where single wedge is not

sufficient

Widening of proximal box in bucco-

lingual dimension.

2 wedges are used

one wedge is inserted from lingual

embrasure area while another is

inserted between the wedge and

matrix band at right angle to first

wedge.

Indicated while treating mesial

aspect of maxillary first premolar

because of presence of flutes in root

near the gingival area.

2 wedges are used, one (larger)

wedge is inserted as used normally,

while the other smaller wedge

(piggyback) is inserted above the

larger one.

Indicated in cases of shallow

proximal box with gingival

recession.

This technique provides closer

adaptation and contour of the matrix

band

العم ساجد ^_^ تم بحمد الله ,,,,,