Referred Pain and Sensations Evoked by Standardized Palpation of the Masseter Muscle in Healthy Participants

Aims: To determine if standardized palpation of the masseter muscle can evoke referred pain and/or sensations in healthy individuals and to compare the mechanical sensitivities in response to three different levels of palpation force. Methods: A total of 32 pain-free individuals participated. The right masseter muscle was divided into 15 test sites. Mechanical sensitivity of the masseter was assessed with three mechanical stimuli (0.5 kg, 1.0 kg, or 2.0 kg) applied by palpometers to the 15 test sites for 5 seconds each site. Participants scored the perceived intensity of pain and unpleasantness of each of the three mechanical stimuli on 0–100 numeric rating scales (NRS). After each stimulus, the duration of aftersensation was measured, and the participants were also asked to indicate areas within the orofacial region with referred pain/sensations. Data were tested using analysis of variance, Tukey post hoc, and McNemar’s tests with a 5% level of significance. Results: Referred pain/sensations were most commonly evoked with the 2.0-kg stimulus (34.4% of participants; P < .05) compared to the 1.0-kg (12.5%) and 0.5-kg stimuli (3.1%). There were significant effects of stimulus intensity on NRS scores for pain and unpleasantness, as well as for aftersensation (P < .05). There were significant effects on NRS scores for pain and unpleasantness for the 1.0- and 2.0-kg stimuli (P < .05) and on aftersensation for the 2.0-kg stimulus (P < .05). Conclusion: These results indicate that referred pain/sensations in the orofacial region are frequent phenomena among healthy individuals during standardized palpation of the masseter muscle.

aftersensation;masseter muscle;mechanical sensitivity;palpation;referred pain

1.Salonen L, Helldén L, Carlsson GE. Prevalence of signs and symptoms of dysfunction in the masticatory system: An epide-miologic study in an adult Swedish population. J Craniomandib Disord 1990;4:241–250.

2.De Kanter RJ, Truin GJ, Burgersdijk RC, et al. Prevalence in the Dutch adult population and a meta-analysis of signs and symp-toms of temporomandibular disorder. J Dent Res 1993;72: 1509–1518.

3.Gesch D, Bernhardt O, Alte D, et al. Prevalence of signs and symptoms of temporomandibular disorders in an urban and ru-ral German population: Results of a population-based Study of Health in Pomerania. Quintessence Int 2004;35:143–150.

4.Bonjardim LR, Lopes-Filho RJ, Amado G, Albuquerque RL Jr, Goncalves SR. Association between symptoms of temporo-mandibular disorders and gender, morphological occlusion, and psychological factors in a group of university students. Indian J Dent Res 2009;20:190–194.

5.Skootsky SA, Jaeger B, Oye RK. Prevalence of myofascial pain in general internal medicine practice. West J Med 1989;1 51:157–160.

6.LeResche L, Mancl LA, Drangsholt MT, Huang G, Von Korff M. Predictors of onset of facial pain and temporomandibular disorders in early adolescence. Pain 2007;129:269–278.

7.Dworkin SF, Huggins KH, LeResche L, et al. Epidemiology of signs and symptoms in temporomandibular disorders: Clinical signs in cases and controls. J Am Dent Assoc 1990;120: 273–281.

8.Benoliel R, Svensson P, Heir GM, et al. Persistent orofacial muscle pain. Oral Dis 2011;17(suppl):s23–s41.

9.Mense S. Nociception from skeletal muscle in relation to clini-cal muscle pain. Pain 1993;54:241–289.

10.Svensson P, Arendt-Nielson L. Clinical and experimental as-pects of temporomandibular disorders. Curr Rev Pain 2000; 4:158–165.

11.Craig AD. Pain mechanisms: Labeled lines versus convergence in central processing. Annu Rev Neurosci 2003;26:1–30.

12.Perl ER. Pain mechanisms: A commentary on concepts and issues. Prog Neurobiol 2011;94:20–38.

13.Hombrebueno JR, Chen M, Penalva RG, Xu H. Loss of synap-tic connectivity, particularly in second order neurons is a key feature of diabetic retinal neuropathy in the Ins2Akita mouse. PLoS One 2014;9:e97970.

14.Sessle BJ, Hu JW, Amano N, Zhong G. Convergence of cu-taneous, tooth pulp, visceral, neck and muscle afferents onto nociceptive and non-nociceptive neurones in trigeminal sub-nucleus caudalis (medullary dorsal horn) and its implications for referred pain. Pain 1986;27:219–235.

15.Mørch CD, Hu JW, Arendt-Nielsen L, Sessle BJ. Convergence of cutaneous, musculoskeletal, dural and visceral afferents onto nociceptive neurons in the first cervical dorsal horn. Eur J Neurosci 2007;26:142–154.

16.Schiffman E, Ohrbach R, Truelove E, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for clinical and research applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral Facial Pain Headache 2014;28:6–27.

17.Tunks E, McCain GA, Hart LE, et al. The reliability of exam-ination for tenderness in patients with myofascial pain, chronic fibromyalgia and controls. J Rheumatol 1995;22:944–952.

18.Svensson P, Baad-Hansen L, Pigg M, et al. Guidelines and recommendations for assessment of somatosensory function in oro-facial pain conditions—A taskforce report. J Oral Rehabil 2011;38:366–394.

19.de Wijer A, Lobbezoo-Scholte AM, Steenks MH, Bosman F. Reliability of clinical findings in temporomandibular disorders. J Orofac Pain 1995;9:181–191.

20.John MT, Zwijnenburg AJ. Interobserver variability in assess-ment of signs of TMD. Int J Prosthodont 2001;14:265–270.

21.Chaves TC, Nagamine HM, de Sousa LM, de Oliveira AS, Grossi DB. Comparison between the reliability levels of man-ual palpation and pressure pain threshold in children who re-ported orofacial pain. Man Ther 2010;15:508–512.

22.Bernhardt O, Schiffman EL, Look JO. Reliability and validity of a new fingertip-shaped pressure algometer for assessing pressure pain thresholds in the temporomandibular joint and masticatory muscles. J Orofac Pain 2007;21:29–38.

23.Futarmal S, Kothari M, Ayesh E, Baad-Hansen L, Svensson P. New palpometer with implications for assessment of deep pain sensitivity. J Dent Res 2011;90:918–922.

24.Kothari SF, Kothari M, Baad-Hansen L, Svensson P. Comparison of techniques for evaluation of deep sensitivity in the craniofacial region. J Orofac Pain 2012;26:225–232.

25.Kothari SF, Kothari M, Zambra RF, Baad-Hansen L, Svensson P. Standardization of muscle palpation—Methodological con-siderations. Clin J Pain 2014;30:174–182.

26.Blanksma NG, van Eijden TM. Electromyographic heterogene-ity in the human temporalis and masseter muscles during static biting, open/close excursions, and chewing. J Dent Res 1995; 74:1318–1327.

27.Korfage JA, Brugman P, Van Eijden TM. Intermuscular and intra-muscular differences in myosin heavy chain composition of the human masticatory muscles. J Neurol Sci 2000;178:95–106.

28.Widmer CG, English AW, Morris-Wiman J. Developmental and functional considerations of masseter muscle partitioning. Arch Oral Biol 2007;52:305–308.

29.Shannon CE. A mathematical theory of communication. Bell Syst Tech J 1948;27:379-423.

30.Zhou X, Ding H, Ung B, Pickwell-MacPherson E, Zhang Y. Automatic online detection of atrial fibrillation based on symbolic dynamics and Shannon entropy. Biomed Eng Online 2014;13:18.

31.Castrillon EE, Exposto FG, Sato H, et al. Entropy of masseter muscle pain sensitivity: A new technique for pain assessment. J Oral Facial Pain Headache 2017;31:87–94.

32.Svensson P, Graven-Nielsen T, Arendt-Nielsen L. Mechanical hyperesthesia of human facial skin induced by tonic painful stimulation of jaw muscles. Pain 1998;74:93–100.

33.Zagury JG, Eliav E, Heir GM, et al. Prolonged gingival cold allo-dynia: A novel finding in patients with atypical odontalgia. Oral Surg Oral Med Pathol Oral Radiol Endod 2011;111:312–319.

34.Wang H, Cao Y, Chiang CY, Dostrovsky JO, Sessle BJ. The gap junction blocker carbenoxolone attenuates nociceptive behavior and medullary dorsal horn central sensitization induced by partial infraorbital nerve transection in rats. Pain 2014;155:429–435.

35.Torstensson T, Butler S, Lindgren A, Peterson M, Eriksson M, Kristiansson P. Referred pain patterns provoked on intra-pelvic structures among women with and without chronic pelvic pain: A descriptive study. PLoS One 2015;10:e0119542.

36.Hsieh CY, Hong CZ, Adams AH, et al. Interexaminer reliability of the palpation of trigger points in the trunk and lower limb muscles. Arch Phys Med Rehabil 2000;81:258–264.

37.Torebjörk HE, Ochoa JL, Schady W. Referred pain from in-traneural stimulation of muscle fascicles in the median nerve. Pain 1984;18:145–156.

38.Graven-Nielsen T, Arendt-Nielsen L, Svensson P, Jensen TS. Stimulus-response functions in area with experimentally in-duced referred muscle pain—A psychophysical study. Brain Res 1997;744:121–128.

39.Rainville P, Feine JS, Bushnell MC, Duncan GH. A psycho-physical comparison of sensory and affective responses to four modalities of experimental pain. Somatosens Mot Res 1992;9:265–277.

40.Sung PS, Zurcher U, Kaufman M. Comparison of spectral and entropic measures for surface electromyography time series: A pilot study. J Rehabil Res Dev 2007;44:599–609.

41.Vierck CJ Jr, Staud R, Price DD, Cannon RL, Mauderli AP, Martin AD. The effect of maximal exercise on temporal summation of second pain (windup) in patients with fibromyal-gia syndrome. J Pain 2001;2:334–344.

42.Greenspan JD, Slade GD, Bair E, et al. Pain sensitivi-ty and autonomic factors associated with development of TMD: The OPPERA prospective cohort study. J Pain 2013; 14(suppl):T63–T74.

43.Price DD, Staud R, Robinson ME, Mauderli AP, Cannon R, Vierck CJ. Enhanced temporal summation of second pain and its central modulation in fibromyalgia patients. Pain 2002;99:49–59.

44.Staud R, Robinson ME, Vierck CJ Jr, Price DD. Diffuse nox-ious inhibitory controls (DNIC) attenuate temporal summation of second pain in normal males but not in normal females or fibromyalgia patients. Pain 2003;101:167–174.

45.Dickenson AH, Sullivan AF. NMDA receptors and central hy-peralgesic states. Pain 1991;46:344–346.

46.Li J, Simone DA, Larson AA. Windup leads to characteristics of central sensitization. Pain 1999;79:75–82.