e. Gingival Margin Trimmers (TRIMMER, GINGIVAL MARGIN). Gingival
margin trimmers (figure 2-9) are used to bevel the enamel at the cervical seat of the
cavity preparation. They include black numbers 77, 78, 79, and 80.
Figure 2-9. Gingival margin trimmers.
2-11. MATRIX RETAINERS AND BANDS
A matrix confines the restorative material in the cavity preparation. It also
establishes proper contours in restorations replacing missing walls of the tooth.
a. Matrix Retainers (RETAINER, MATRIX, DENTAL). Matrix retainers (figure
2-10) are used to hold and adjust matrix bands on the teeth. These include Ivory
retainers numbers 1 and 9 and the contra-angle Tofflemire retainer that comes in adult
and junior sizes.
Figure 2-10. Tofflemire matrix retainer.