Assessment of Mechanical Pain Thresholds in the Orofacial Region: A Comparison Between Pinprick Stimulators and Electronic Von Frey Device

Aims: To compare mechanical pain thresholds (MPTs) in the orofacial region assessed with two different approaches: with an electronic von Frey (EvF) device and with custom-made weighted pinprick stimulators. The test-retest reliability, variability of MPTs, and time duration of each test were also compared, as well as the ability of each test to create stimulus-response (S-R) curves. Methods: A total of 16 healthy volunteers participated. The MPT and S-R curve measurements were done with the two different techniques at three sites: on the skin of the right cheek (face), on the buccal gingival mucosa of the right upper premolar region (gingiva), and on the tip of the tongue (tongue). The same protocol was repeated 1 to 2 weeks later to determine test-retest reliability. Results: The MPT measurements with the EvF device were significantly faster (74.4 +/- 20.8 seconds) than those with the pinprick stimulators (196.1 +/- 33.0 seconds; P<.001). The absolute MPT values obtained with the EvF device were significantly higher than the values obtained with the pinprick stimulators at all test sites (P<.001). MPTs assessed with the EvF device showed higher reliability (intraclass correlation coefficient [ICC] = 0.77-0.94) than MPTs assessed with the pinprick stimulators (ICC = 0.57-0.84; P =.041). The reliability of the S-R curves was excellent for both methods with no significant differences between the methods (P =.403). Conclusion: This study indicates that MPTs tested in the orofacial region with the EvF device were significantly higher than MPTs tested with the pinprick stimulators. However, the EvF device can be used with higher reliability and less time consumption for assessment of MPTs in the orofacial region than the pinprick stimulator technique, and also allows comparable construction of S-R curves.