Spatio-temporal Effects of Standardized Palpation on Referred Sensations and Pain from the Masseter Muscle in Healthy Individuals

抄録

The aims of this study were to investigate the influence of different spatio-temporal conditions of palpation stimulus on occurrence of referred pain/sensations in healthy participants.

Participants comprised 32 pain-free individuals(mean age, 25.7±5.3 years)according to the Diagnostic Criteria for Temporomandibular Disorders. The right masseter muscle was equally divided into 15 test sites. Mechanical sensitivity was assessed with three mechanical stimuli (0.5-kg, 1.0-kg, or 2.0-kg) applied to the 15 test sites with three different durations(2-s, 5-s, or 10-s)using palpometers. Participants scored the intensity of perceived pain and unpleasantness for the three mechanical stimuli on a 0-50-100 numerical rating scale(NRS)after each stimulus. If the participant reported referred pain/sensations after a stimulus, they indicated areas of referred pain/sensations on a digital drawing.

The occurrence of referred pain/sensations was significantly higher with 10-s palpation stimulus than with 2-s palpation stimulus for 1.0-kg and 2.0-kg stimuli(P < 0.05 each).

There was no significant relationship between test site and occurrence of referred pain/sensations. Stimulus intensity, duration and test site significantly affected NRS scores for pain and unpleasantness(P < 0.05 each).

These findings showed that referred pain/sensations from the masseter muscle were time- and intensity-dependent, but not site-dependent processes originating from

standardized palpation of the masseter muscle. In addition, our results indicate that duration, intensity and test site of palpation stimuli for masseter muscle is associated with muscle pain diagnosis related to referred pain in the orofacial area.