Compare Sharp Instruments with Dull Ones, and Know When to Replace

New instruments serve as a gold standard when sharpening dull instruments. The gold standard serves as a reminder of the original instrument design, including proper contour, angles and cutting edges. These ideal characteristics should be maintained during the life of the instrument, even with frequent sharpening. When the instrument being maintained starts to deviate from the gold standard, replacement should be considered.3

If the thickness of the terminal edge starts to be noticeably thinner than the gold standard and the instrument has lost strength, the tip could easily break off upon activation. Similarly, if the blade edge angulation starts to deviate from the original design, the integrity of the instrument blade has been compromised and the instrument should be replaced (Figure 3).4 In some cases, clinicians may choose to alter the original instrument design with the specific purpose of customizing the instrument for use in a particular location; for example, a specific cutting angle may be created to reach into a furcation entrance or root groove.5

Figure 3. Decision to Replace an Instrument.
Illustration showing characteristics of a blade to determine when it should be replaced
When an instrument loses its original characteristics, it should be replaced. A number of factors could cause the instrument to lose its original characteristics some are shown.