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Background: Pain in the orofacial region is often reported after whiplash trauma. However, prospective studies evaluating clinical signs related to orofacial pain and disability in whiplash populations are rare. The aim of the present study was to evaluate clinical signs related to pain and dysfunction in orofacial and neck regions after whiplash trauma, in a short- and long-term perspective.

Methods: In total, 84 cases (48 women) diagnosed with neck distortion after a car accident and 116 controls (68 women) were examined within 1 month, and 49 cases (27 women) and 71 controls (41 women) were re-examined 2 years later. Outcome measures were pain on palpation of jaw and neck muscles and maximal jaw opening. Analysis was performed using mixed-models.

Results: Cases and women were at higher risk for pain on palpation of jaw muscles (OR:7.7; p < 0.001 and OR:3.2; p = 0.010 respectively) and neck muscles (OR:12.7; p < 0.001 and OR:2.9; p = 0.020 respectively) but with no significant effect of time. Cases and women also had lower maximal jaw opening (−3.1; p = 0.001 and −3.3; p = 0.001 respectively). There was no significant time effect, but a significant interaction between cases and time (2.2; p = 0.004).

Conclusion: Individuals with a whiplash trauma present a higher risk for pain on palpation in jaw and neck muscles both in a short- and long-term perspective, but show normal jaw movements. No time effect suggests that cases do not spontaneously improve nor get worse. Investigating pain on palpation in the jaw and neck muscles after whiplash trauma can identify individuals at risk for developing long-term orofacial pain and dysfunction.

Significance: Orofacial pain is often reported after whiplash trauma but most previous studies concerning orofacial pain in whiplash populations have been questionnaire studies. Cases with a previous whiplash trauma and women, in general, had higher risk for pain on palpation in the jaw and neck region. Investigating pain on palpation after a whiplash trauma can help to identify individuals at risk of developing long-lasting pain in the orofacial region.

Objectives: To explore predictive factors for the development and maintenance of jaw pain over a 2-year period.

Methods: One hundred nineteen cases (73 women) and 104 controls (59 women), mean age 34.9 years (SD 13.9), attended baseline and 2-year follow-up examinations. The whiplash cases visited the emergency department at Umeå University Hospital, Sweden, with neck pain within 72 h following a car accident, and baseline questionnaires were answered within a month after trauma. Controls were recruited via advertising. Inclusion criteria were age 18–70 years, living in Umeå municipality and Swedish speaking. The exclusion criterion was neck fracture for cases and a previous neck trauma for controls. Validated questionnaires recommended in the standardized Research Diagnostic Criteria for temporomandibular disorders were used. Jaw pain was assessed by two validated screening questions answered with “yes” or “no.” A logistic regression analysis was used to predict the outcome variable jaw pain (yes/no) after 2 years.

Results: Whiplash trauma did not increase the odds of development of jaw pain over a 2-year period (OR 1.97, 95% CI 0.53–7.38). However, non-specific physical symptoms (OR 8.56, 95% CI 1.08–67.67) and female gender (OR 4.89, 95% CI 1.09–22.02) did increase the odds for jaw pain after 2 years.

Conclusion: The development and maintenance of jaw pain after whiplash trauma are primarily not related to the trauma itself, but more associated with physical symptoms.

Clinical relevance: The development of jaw pain in connection with a whiplash trauma needs to be seen in a biopsychosocial perspective, and early assessment is recommended.

Gender differences in pain reporting and prevalence have been demonstrated. As gender of examiner also affects reporting of pain on palpation, the aim of this study was to evaluate the effects of examiner gender on palpation performance using three different palpation methods. Examiners of both genders were instructed on the correct technique for each palpation method by either a female or male instructor. The target was to achieve a pressure of 100 kPa, corresponding to the 1 kg of force for muscle palpation described in the diagnostic criteria for temporomandibular disorders (DC/TMD). All examiners performed traditional palpation with the index finger, palpation with a palpometer, and a novel bimanual palpation with visual feedback, in a randomized order. The examiner's gender, and its interaction with the gender of the instructor did not significantly affect magnitude, accuracy, or precision of the pressure applied. The method of palpation was the only factor that significantly impacted all metrics. The palpometer achieved the lowest palpation magnitude (mean pressure applied = 113.7  kPa, 95% CI: 109.8-117.6), the highest accuracy (absolute difference = 15.7  kPa, 95% CI: 12.3-19.1), and the highest precision (mean coefficient of variation = 6.8, 95% CI: 6.0-7.6), followed by bimanual palpation and traditional palpation. The results suggest that gender differences in pain reporting in patients are not likely to be a result of the technical aspects associated with the gender of the examiner. Instead, these differences may be attributed to other factors, such as sociocultural influences.

Normal jaw opening-closing involves simultaneous jaw and head-neck movements. We previously showed that, in men, integrated jaw-neck movements during jaw function are altered by induced masseter muscle pain. The aim of this study was to investigate possible sex-related differences in integrated jaw-neck movements following experimental masseter muscle pain. We evaluated head-neck and jaw movements in 22 healthy women and 16 healthy men in a jaw opening-closing task. The participants performed one control trial and one trial with masseter muscle pain induced by injection of hypertonic saline. Jaw and head movements were registered using a three-dimensional optoelectronic recording system. There were no significant sex-related differences in jaw and head movement amplitudes. Head movement amplitudes were significantly greater in the pain trials for both men and women. The proportional involvement of the neck motor system during jaw movements increased in pain trials for 13 of 16 men and for 18 of 22 women. Thus, acute pain may alter integrated jaw-neck movements, although, given the similarities between men and women, this interaction between acute pain and motor behaviour does not explain sex differences in musculoskeletal pain in the jaw and neck regions.