Pain related to mandibular block injections and its relationship with anxiety and previous experiences with dental anesthetics

Objective. Anesthetic injections should reassure patients with the prospect of painless treatment, but for some patients it is the main source of their fear. We investigated pain resulting from mandibular block injections in relation to anxiety and previous experience with receiving injections.
Study Design. Patients (n = 230) filled out questionnaires before oral surgery. They were then asked to raise their hand when they felt pain as a result of the injection. The injection was administered, and pain intensity (11-point numeric rating scale) and pain duration (in seconds) was measured.
Results. In general, patients expected (mean 4.2, SD 2.7) significantly more pain than they experienced (2.4 + 2.2). About 8.3% of patients reported a score in the range of 7 to 10. On average, pain lasted for 6.2 seconds (range 1-24.5 s), ~36% of patients raised their hand for <2 seconds, and 14.6% raised their hand for >10 seconds. Pain was significantly positively associated with anxiety and the way previous injections were experienced.
Conclusions. Mandibular block injections can be considered to be mildly painful, with pain lasting only a few seconds. The pain experience of a mandibular block seems only partly dependent on experienced anxiety and previous experiences with receiving injections.