c. Motor-Driven Rotary Finishing Instruments.
(1) Finishing burs (BUR, DENTAL, FINISHING, AHP or SHP). Finishing burs
(figure 2-24) are used to even the margins and polish the surface of dental restorations.
They are available in round, oval, bud, sugarloaf, and tapered fissure shapes. Round and
bud shapes are available for both AHP and SHP; the remaining shapes for AHP only.
Figure 2-24. Finishing burs.
(2) Mandrels (MANDREL, DENTAL HANDPIECE). Mandrels are used to
hold disks and wheels during their use. Snap-head mandrels (figure 2-25) are used only
for sandpaper and linen-backed disks with a special brass center which snaps on to the
mandrel. Screw-type mandrels are used to mount abrasive disks and unmounted stones.
Figure 2-25. Snap-head mandrel.
(3) Abrasive and polishing disks (DISK ABRASIVE). Disks of various
diameters and surfaced with various abrasives upon different types of backings are used
for purposes ranging from rapid cutting of enamel to fine polishing of restorations (see
figure 2-26). They include sandpaper disks (abrasive on one side), double-cutting disks
(abrasive on both sides), and diamond disks. Diamond disks must be cooled with water
or air when used.
Figure 2-26. Unmounted abrasive disks, screw-in type and snap-on type.