Sickle Scalers and Subgingival Scaling
Sickle instruments are designed with parallel cutting edges, a triangular body, and a pointed toe.
Sickle instruments are designed with parallel cutting edges, a triangular body, and a pointed toe. The cutting edges and shanks are either curved or straight. Sickles are paired (same design on each end) or nonpaired (different designs on each end). A variety of a sickle designs are available to address different calculus locations and sizes, as well as gingival conditions. They can be used 1 mm to 2 mm subgingivally.
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H6/H7 Anterior Sickle
The H6/H7 is a popular anterior sickle that is double ended, relatively thin, and contra-angled. It has only one cutting edge on each end. The 5/33 anterior design has two different blades on each end; one is thinner than the other. Designed for posterior supragingival interproximal scaling, the 204 designs are double ended, triangular in shape, and wider than some anterior sickles. The Montana Jack Scaler 3 is contra-angled with a universal design.
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Nevi 1
The Nevi 1 is an anterior instrument with two different ends; one for interproximal calculus and stain and the other, a disc, for lingual stain. The Nevi 1/H5, an anterior design, has a disk end, and a larger #15 curved, thin end for interproximal and cervical areas. The Nevi 2 and 3 are double-ended posterior sickles with a curved, long, narrow blade for light to moderate interproximal calculus; the 3 is ultrathin. The Nevi 4 is the widest instrument designed for posterior heavy deposits.
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Appropriate Technique
When using a sickle subgingivally consider three things: its purpose, tissue tone, and design. The purpose should be for initial debridement and scaling, not for final debridement/root planing. Instead, curets or ultrasonic inserts/tips are indicated for finishing root surfaces. Second, evaluate the tissue tone. Gingiva that is elastic or inflamed is ideal for inserting a sickle at or subgingivally to the gingival margin. If the gingiva is tight/taut, the sickle is not indicated subgingivally. Last, consider the sickle design. A very thin diameter and curved sickle is appropriate for adapting to light deposits and subgingival root anatomy. However, a wide sickle with straight blades is for heavier deposits. For example, consider 6 mm pocket depth in the anterior or posterior with supragingival and subgingival deposits. Choose a sickle for initial debridement of supragingival calculus and subgingival deposit near the gingival margin, and follow with an ultrasonic insert/tip or curet. A sickle might also be applied after ultrasonic instrumentation and prior to final debridement. A sickle, with a triangular shape and pointed toe, cannot successfully adapt to the root near the epithelial attachment due to the proximity of the gingiva and the narrow and curved root anatomy. The back of the sickle is likely to impinge upon the gingiva and cause discomfort.
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Adaptation Is Key
Adaptation includes having the terminal shank parallel with the tooth, using the terminal 1 mm to 2 mm of the cutting edge, and applying about an 80° blade-to-tooth angle. The sickle’s pointed toe may gouge or striate the cementum; therefore, it is important to keep the terminal aspect of the blade, instead of the point, adapted to prevent root roughness.
