Which is NOT an ideal fulcrum position when providing local anesthesia?

When providing local anesthesia, an ideal fulcrum position is critical for the stability and control of the needle during the injection process. The choice where the clinician's arm is against the patient's arm is not considered an ideal fulcrum position. This is because using the patient's arm creates an unstable fulcrum; any movement from the patient can lead to variations in the clinician's hand positioning, increasing the risk of discomfort or complications during the injection.

In contrast, having the clinician's finger on the patient's face and the elbow on a stable part of the patient’s body are both considered ideal. These positions allow for a solid point of reference, maintaining control over the syringe and ensuring that the needle can be accurately placed without unexpected movements. Stability is paramount in ensuring both the effectiveness of the anesthesia and the comfort of the patient, which underlines the importance of proper fulcrum positioning in dental practices.