This study examined the hypothesis that instructing patients to focus on their sensations (sensory focus) during root canal therapy reduces painful response. Before dental treatment, patients were randomly assigned to one of four audiotaped conditions: sensory focus with and without procedural information, procedural information, or no-intervention. Patients were categorized as to how much control they desired and felt. The "high desire for control/low felt control" subgroup's sensory pain intensity scores in the sensory focus condition were significantly lower than the "high desire for control/low felt control" subgroup's sensory intensity scores in the no-intervention comparison condition. This was true immediately after treatment (F(1,303) = 13.37; p < or = .001) and 1 week after treatment (F(1,303) = 14.30; p < or = .001). Immediately after treatment, the high desire for control/low felt control subgroup in the sensory/procedural condition was significantly lower on sensory pain intensity scores than the high desire/low felt subgroup in the no-intervention condition (F(1,303) = 3.75; p < or = .001). This difference was not observed on the 1-week recall of pain. Adding procedural information to the instructions to focus on sensation did not increase the pain-reducing effects. Results extend prior findings that sensory focus significantly reduces sensory pain intensity only among patients who are classified as having a high desire for control and low perceived control. These results are congruent with theoretical arguments that coping preferences moderate the reaction of patients to various therapeutic strategies.