QUESTION: I am having trouble generating strokes that are powerful enough to remove tenacious calculus. Do you have any suggestions?
ANSWER: Grasp is key to generating powerful working strokes, and the position of the middle finger is crucial to achieving this ideal grasp. When grasping any bladed scaling instrument, the shank or handle should rest on the side of the middle finger, on the corner of the pad, next to the fingernail (Figure 1). If the shank or handle is rested on the fleshy, soft center of the pad of the middle finger, a light deplaqueing stroke is possible, but significant effort is then needed to create a firm stroke suitable for calculus removal (Figure 2). This may seem like a small difference, but the position of the middle finger is critical for control, leverage, and lateral pressure. For example, when positioned at 9 o’clock to scale the distal surface of the mandibular right second molar from the buccal aspect with a Gracey 13/14 or universal curet, the shank or handle should rest on the bony side of the middle finger, while the stroke is activated with a side-to-side wrist motion, to create a firm, well controlled stroke (Figure 3). During scaling, gloved fingers can sometimes become slippery, and the curet shank can slip down onto the fleshy middle part of the pad of the middle finger (Figure 4). If this happens while scaling across the distal surface, a substantial amount of lateral pressure will be lost, and the stroke will become weak. The bony side of the middle finger must remain underneath the instrument shank or handle so you can pivot on the fulcrum and attain the leverage necessary to make the instrument work.
Using the side of the middle finger is an effective position for two reasons. First, it lifts the handle so you get proper working angulation. If you grasp with the soft pad of the middle finger, the handle drops too low and the blade angulation tends to be too closed on the distal or too open on the mesial. The handle needs to be uprighted by resting it on the top of the side of the middle finger. The second reason is the need for resistance from the fulcrum. By placing the bony part of the finger underneath the instrument, a strong pivot point is created. When you slip down onto the soft fleshy part of the finger, there is nothing to lean against, leaving you with inadequate leverage and pressure. This problem also occurs when a Gracey 11–12 curet or universal curet is used on the mesial surface of a mandibular first molar from the buccal or lingual approach. Scaling with the shank resting on the fleshy, middle part of the pad will result in a weaker stroke, and the blade will be too open as you scale across the mesial surface.
So remember that when scaling with all curets and scalers, the shank or handle of the instrument should always rest on the bony corner of the middle finger, next to the fingernail. This offers the firmest fulcrum point—providing the best control, leverage, and lateral pressure.
From Dimensions of Dental Hygiene. December 2011; 9(12): 62.