The disc end of the Nevi 1 scaler can be used to remove heavy lingual deposits in the anterior areas using a pull stroke. This is similar to the hoe, but it has a curved blade. Due to the curved disk shape and cutting edge along the entire disk, it is more universal and can be used with horizontal, vertical and oblique strokes.
The other end is a sickle type scaler and is good for use on the lingual surface. The thin tip adapts easily and is strong enough to tackle interproximal deposits and line angle stain (Figures 51‑55).
In use, the Nevi 2 scaler easily reaches under the contact points in posterior areas to remove calculus with minimal tissue trauma due to its very thin, contra-angle design. Often, sickle scalers are thicker and are difficult to navigate under the contact areas without traumatizing the tissue. In addition, sickle scalers typically have a straight design on the working end. This straight design makes it difficult to adapt to many of the posterior surfaces and maintain correct hand and instrument position. The contra angle design in the Nevi 2 scalers allows for a neutral wrist position while scaling and thus aids in ergonomic practice (Figures 56‑57).
Nevi 3 and 4 are posterior scalers. The Nevi 3 (Figure 58) has dual cutting edges and a slim shank with a slight contra-angle to get into posterior areas. Nevi 4 (Figure 59) has a stronger shank and longer, tapered dual blades to get under heavier deposits in the posterior.