Establishing an Effective Extraoral Fulcrum

QUESTION: I find scaling deep pockets on maxillary posterior teeth difficult. I use an intraoral rest but I feel like my stroke is not very powerful and I cannot go deep enough. Do you have any suggestions?

ANSWER: A common problem when using intraoral fulcrums for the maxillary posterior teeth is the split fulcrum. Whenever you are forced to separate your fulcrum finger from your grasping fingers, the resulting split causes a loss of stability and strength in your working stroke (Figure 1). Even if you switch to a palm up intraoral rest (Figure 2), you still have to split your fulcrum to scale to the base of a deep pocket.

Intraoral rests are most stable and powerful when your fulcrum and middle fingers stay close together and wrist motion is used to activate your stroke. This is virtually impossible when scaling deep pockets on the maxillary molars. When you reach back, the separation of your fingers makes it difficult to insert your instrument deeply into the pocket. You lose power because you must “finger flex” in order to make a longer, deeper stroke (Figure 2). Intraoral rests in this area limit your stroke’s arc of movement and often force you to bend your wrist in an awkward, ergonomically unsound position. A better alternative is to use an extraoral fulcrum to allow your whole hand to activate a more powerful stroke (Figures 3 and 4). Note that your wrist can be kept in a neutral position.

First, you must approach from a 9:00 position. Second, adjust your grasp so you’re using an extended grasp further down the handle than usual, away from the working end. For the maxillary right posterior teeth, the extraoral rest is palm up on the right side of the face (Figure 3). For the maxillary left posterior teeth, establish a palm down extraoral rest on the left side of the face (Figure 4). This is the same extraoral rest that you use with ultrasonic scaling. Rest on the skin overlying the mandible and avoid pinching the lip against the teeth. If you are using Gracey curets, make sure the lower shank is parallel to the surface you’re scaling before starting your stroke.

Sitting at 9:00 when using these ex tra oral rests allows the handle to rest on the bone between the second and third knuckles of your in dex finger, instead of on the soft web of your hand. This is a more stable grasp that allows maximum force when making your stroke. If you approach from the 7:00 or 8:00 position, your arm and hand will be in a too far forward position. This will force you to drop the instrument handle into the web of your hand, resulting in a weaker grasp and a less stable stroke.