A matrix band is used to temporarily provide the missing walls of the tooth and the shape of the restoration. The most popular matrix system is called the Tofflemire matrix. Tofflemire matrix band are manufactured out of stainless steel in two different thicknesses—.002 inch and .0015 inch. Different styles are available to meet the needs of most tooth restorations.
The thicker matrix band (.002”) provides more resistance when packing a cavity preparation, while the thinner band (.00 15”) is more adaptable. Most bands are flat pieces (strips) of stainless steel that are adapted by the operator to the contour of the tooth being restored. Preconditioned versions of the Tofflemire band are also available.
The Tofflemire matrix band is held in place in the mouth by a Tofflemire retainer. The retainers are available in three styles: adult universal, adult contra-angle, and pedodontic universal.
A wedge is used to hold the matrix band in contact with the interproximal area of the preparation, to separate the teeth, and to compensate for the thickness of the matrix. Once the wedge and matrix band are removed, the contact point to the adjacent tooth is restored. This ensures a smooth surface without overhang when packing the restorative material.
Wedges are commercially available in various styles, both wooden and plastic. The anatomical pattern wedges are designed to adapt better to the tooth structure. Wedges are available under the trade names of Wizard, Wizard Anatomical, Nylon, and Sycamore Wood.
PLACEMENT OF THE TOFFLEMIRE BAND
To place a Tofflemire band, the dentist and assistant perform the following steps:
1. After a matrix band of the appropriate style is selected, it is wrapped so the ends are placed together. While the band is held in that fashion, the occiusal edge of the band is placed in the diagonal slot on the box of the retainer. The outer nut of the retainer is turned slightly clockwise to hold the band. The band is closed slightly by turning the inner nut of the retainer.
2. The assembled matrix band is placed over the prepared tooth and sized. Any necessary adaptation is now made to the band to make it fit flush to the prepared tooth surfaces. It must also make contact with the adjacent tooth. A ball burnisher may be used for contouring the band.
3. The matrix band is then carefully seated in place below the open gum margin. While gentle pressure is applied to the top of the band, the inner knob of the retainer is tightened clockwise until the band fits snugly around the tooth. A check is made to ensure that the band is adapted tightly to the prepared tooth and that the contact area—is made to the adjacent tooth. Note that the slot side of the box is placed toward the tooth and the retainer handle extends from the mouth on the buccal side of the tooth.
4. A wedge is then selected and placed interproxirnally to ensure that the mesioproximal and/or disto-proximal contact of the band is maintained and that the two teeth are slightly separated. This separation assures the firmness of the contact to the adjacent tooth by compensating for the thickness of the matrix band.
5. After completion of the restoration’s placement, the wedge is removed. The retainer is released by rotating the outer knob counterclockwise. The retainer is removed, and the matrix band is carefully lifted free of the preparation. The matrix must not be removed until the restoration has had sufficient time to set.
A Note of Caution: Since a matrix is made of steel, it can cut your finger, similar to a paper cut.
Specialized Matrix band
Nonmetallic (Mylar) strips are available for use with resin restoratives. Many other specialized matrix band are also available such as:
• Auto matrix. A retainerless version of a metal matrix band.
• Omni-matrix. A disposable version of the Tofflemire system featuring a metal band in a plastic retainer.
• Dead soft stainless steel. Thinner than conventional Tofflernire matrix band with no memory so they all hold their shape.
• Cervical matrices. Metal or nonmetallic specialized matrices for Class V (cervical) restorations.
• Bond-a-Band. A nonmetallic band that becomes a part of the composite restoration and does not require a retainer.
• Cure-Thru squeeze matrices. A retainerless version of an anatomical non-metallic matrix.
• Mylafonns. An anatomical retainerless matrix band system for cosmetic bonding of the anterior teeth.
• Mylar strips. Clear plastic bands for anterior composite resins, dental radiology.