Review article
Prevalence of whiplash trauma in TMD patients:
a systematic review
B . H €AG G M A N - H E N R I K S O N* †, M . R E Z V A N I† & T . L I S T† ‡ *Department of Odontology/Clinical Oral Physiology, Umea University, Umea, †Department of Orofacial Pain and Jaw Function, Malm€o University, Malm€o and‡Department of Rehabilitation Medicine, Skane University Hospital, Lund, Sweden
SUMMARY The purpose of this systematic review was to describe the prevalence of whiplash trauma in patients with temporomandibular disorders (TMDs) and to describe clinical signs and symptoms in comorbid TMD/whiplash compared with TMD localised to the facial region. A systematic literature search of the PubMed, Cochrane Library and Bandolier databases was carried out for articles published from 1 January 1966 to 31 December 2012. The systematic search identified 129 articles. After the initial screening of abstracts, 32 articles were reviewed in full text applying inclusion and exclusion criteria. Six studies on the prevalence of neck trauma in patients with TMD met the inclusion criteria and were included in the review. Two of the authors evaluated the methodological quality of the included studies. The reported prevalence of whiplash trauma ranged from 84% to 70%
(median 35%) in TMD populations, compared with
17–13% in the non-TMD control groups.
Compared with patients with TMD localised to the facial region, TMD patients with a history of whiplash trauma reported more TMD symptoms, such as limited jaw opening and more TMD pain, and also more headaches and stress symptoms. In conclusion, the prevalence of whiplash trauma is higher in patients with TMD compared with non- TMD controls. Furthermore, patients with comorbid TMD/whiplash present with more jaw pain and more severe jaw dysfunction compared with TMD patients without a history of head–neck trauma. These results suggest that whiplash trauma might be an initiating and/or aggravating factor as well as a comorbid condition for TMD.
KEYWORDS:facial pain, jaw pain, neck pain, systematic review, temporomandibular joint disorder, whiplash injuries
Accepted for publication 27 November 2013
Introduction
Pain and dysfunction are common in the population and can have a negative effect on health and well- being, especially when the oro-facial region is affected (1). Patients with temporomandibular disorders (TMDs) typically report jaw/face pain, pain on jaw movements, and impaired jaw mobility (2). The per- ceived treatment need owing to TMD is estimated within the range of 5–15% (3), which means that dentists will frequently meet patients with TMD of varying severity in their daily practice.
The aetiology of TMD is considered to be multifac- torial, with factors such as general health, systemic diseases, psychological, psychosocial, and gender fac- tors, together with local factors such as overload due to bruxism, contributing to the overall risk. It has also been reported that indirect trauma caused by a whip- lash trauma can be a contributing factor (4). It has been suggested that as many as one of four patients with TMD has a history of head/neck trauma in prox- imity to the development of their TMD pain (5) and that these patients have a poorer prognosis (6). There is however a limited number of studies reporting on Journal of Oral Rehabilitation 2014 41; 59--68
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the prevalence of TMD related to neck trauma, and thus, there is currently a gap in the knowledge in this area.
The term whiplash describes a hyperextension–flex- ion trauma to the neck. The incidence in Sweden is about 2 per 1000 inhabitants, mostly from traffic acci- dents but also from other traumas (7). Even though a majority of individuals exposed to a whiplash trauma will recover, about one in three will develop long- lasting problems; whiplash-associated disorders (WADs) (8). These patients report a range of symp- toms such as dizziness, sleeping problems, cognitive problems, and a reduced quality of life (9), in addition to the most common symptoms, headaches and neck pain (9, 10).
Neck pain is often also reported in patients with TMD pain and vice versa. Thus, patients with TMD often report pain not only in the jaws and face, but also in the neck region (11–14), and patients with neck pain often report TMD (15, 16). Recent studies have suggested that the relation between symptoms in the trigeminal and spinal regions shows a dose–response- like pattern (17) as well as a reciprocal influence on the incidence of new symptoms in both regions (18).
Furthermore, there is a functional integration between the jaw and neck regions (19, 20), and as jaw function rely on linked motor control of the jaw and neck motor systems, pain and dysfunction in the neck may impair jaw function. An association has been shown between neck pain and neck dysfunction and dis- turbed jaw function following whiplash trauma. The findings include disturbed jaw–neck motor function in terms of decreased movement amplitudes, disturbed coordination, and impaired endurance (21–23) as well as frequent jaw–face pain (24).
Various explanatory models have been presented for the development of TMD after whiplash trauma.
An early theory proposed that a whiplash trauma to the head and neck could cause a ‘mandibular whip- lash’ by overstretching or compression of the tempo- romandibular joint (TMJ) (25). Later studies refuted this idea (26) and instead suggested an indirect injury mechanism (27). The notion of a neurobiological basis is supported by prospective studies showing that about a third of individuals develop TMD pain after neck injury, despite not showing any structural dam- age to the TMJ (28). In a recent systematic review, we reported an increased prevalence of TMD pain in whiplash populations (29). This finding suggests that
a whiplash trauma could be a risk factor for the development of TMD. If this is the case, it would be reasonable to assume that among TMD populations, i.e. patients seeking care for jaw pain and dysfunc- tion, a higher prevalence of a history of head/neck trauma would be present compared with healthy con- trol groups without TMD. There is, however, limited knowledge to whether this is the case, and therefore, the aim of this review was to address this research question.
The aim of this study was to assess by systematic review of the literature, (i) the prevalence of whiplash trauma in patients with TMD and (ii) clinical signs and symptoms in comorbid TMD/whiplash compared with TMD localised to the facial region.
Materials and methods
Inclusion and exclusion criteria
Inclusion criteria for this review were clinical studies in adult patients (>18 years) reporting history of whiplash trauma in a TMD population. Articles were excluded if they were not based on a TMD population or if data from the same cohort had been reported in another article (dual publication). Experimental stud- ies and narrative reviews were excluded from the review.
Literature search
The search strategy was designed to identify studies that reported the prevalence of whiplash trauma in patient populations with TMD. The search encom- passed all articles that were (i) indexed in PubMed, the Cochrane Library, and Bandolier, (ii) published in English, Swedish, or German, and (iii) published between 1 January 1966 and 31 December 2012.
The search terms used for PubMed were as follows:
‘Whiplash injuries’ [MeSH] or ‘Whiplash Associ- ated Disorders’ or ‘Whiplash’ and
‘Temporomandibular joint disorder’ [MeSH] or
‘Craniomandibular disorders’ or
‘Temporomandibular disorders’ or ‘Temporoman- dibular Joint Dysfunction’ or
‘Jaw pain’ or ‘Facial Pain’.
For the Cochrane Library and Bandolier database, the search strategy included the terms ‘Whiplash’ and
‘Craniomandibular disorders’ or ‘TMJ’ or ‘TMD’. After the search of the databases, reference lists in original articles and review articles were hand-searched to identify additional studies.
Procedure
After the database search, two of the authors (BH and MR) independently read all titles and abstracts to identify potentially eligible articles for inclusion. All studies identified as potentially eligible by one of the reviewers were retrieved in full text and reviewed by both reviewers applying the inclusion criteria. Dis- agreement was resolved by discussion among the investigators. Authors were not contacted for missing information.
The data extracted from the studies were study set- ting, study design, study sample, number of subjects (age and gender), the diagnostic criteria for TMD and whiplash, the prevalence of whiplash trauma, main results, and author’s conclusions.
Quality assessment
Two of the authors (BH and TL) independently evalu- ated the quality of the included studies using a scor- ing system with a standardised 21-item checklist modified from MacFarlane (30). Each criterion was scored as ‘yes’, ‘no’ or ‘unable to determine’. Only criteria scored as ‘yes’ gave a score, which added up to give the total quality score, and results were pre- sented as percentages of total attainable score for each paper. After the independent assessments of the indi- vidual items, which rendered the total quality scores, the interreliability of the two reviewers was calculated with kappa statistics. All articles were discussed to verify appraisal process until consensus was reached.
Disagreements on individual item scores were resolved with discussion. The reviewers were experi- enced oro-facial pain researchers.
Results
The systematic search of three databases together with the hand search identified a total of 129 articles (Fig. 1). After the initial screening of abstracts, 32 articles were retrieved and reviewed in full text. Of these, a total of 26 articles were excluded (Table 1).
The main reasons for exclusion were that studies were
not based on TMD populations (62%), did not report original data (27%), or did not define TMD/trauma groups (11%). Six studies (5, 31–35) on the preva- lence of whiplash trauma in patients with TMD met the inclusion criteria and were deemed eligible for inclusion (Table 2).
Two of the authors independently evaluated the methodological quality of each identified study. The quality score for the included studies ranged from 20% to 65% with a median score of 50%. There was a good agreement between the two investiga- tors in the scoring of the individual items (kappa:
082), which were used to calculate the total quality score.
Fig. 1. Flow diagram of search result, screening of abstracts, and included and excluded articles.
For all included studies, the history of whiplash trauma was self-reported. The criteria for TMD diag- nosis varied between the studies, with only one study applying the research diagnostic criteria/temporoman- dibular disorders (RDC/TMDs).
The reported prevalence of whiplash trauma in the TMD groups ranged from 84% to 70% (median 35%). Two of the six included studies reported a prevalence of whiplash trauma for non-TMD control groups of 17% (32) and 13% (33).
Compared with TMD patients without a history of neck injury, TMD patients with a history of whiplash trauma reported more TMD pain, more severe jaw dysfunction, and more headaches, stress, dizziness, and sleeping problems (Table 2).
Discussion
This systematic review suggests that the prevalence of whiplash trauma is higher in patients with TMD com- pared with non-TMD control groups, suggesting that neck trauma is a comorbid condition for TMD. In
addition, the data suggest that TMD patients with a history of whiplash trauma have more TMD pain and more severe jaw dysfunction, compared with TMD patients without a history of neck injury.
In the present review, there were large variations between the primary studies in the reported preva- lence of whiplash trauma, with the highest prevalence (70% and 54%) reported in two private TMD clinics (33, 34). The other studies based in TMD clinics reported prevalence between 245% and 397% (5, 31, 32), whereas the only study not based in a TMD clinic reported the lowest prevalence of 84% (35).
This study also had the lowest quality score of all included studies, and thus there are uncertainties with regard to the reliability of the reported data from this study. It is reasonable to assume that the varia- tion between studies reflects the differences in TMD populations between the clinics, with patients with more severe TMD symptoms being more likely to seek care in, or be referred to, specialist TMD clinics. The reported median prevalence of whiplash trauma was 35%, which compared with the data from the non- TMD control groups in two of the included studies (32, 33) provide some evidence of increased preva- lence of neck trauma in TMD. There is no reliable data on the prevalence of whiplash trauma in the general population, but it has been estimated that approximately 6% of the US population have late whiplash syndrome (8).
The data from the present review indicate that TMD patients with a history of whiplash trauma have more TMD pain and more severe jaw dysfunction, compared with TMD patients without a history of neck injury (5, 31–35). These results are in line with previous studies, which suggest that patients with TMD and whiplash comorbidity have more severe TMD pain and dysfunction (36), seem to have a poorer prognosis for recovery, and seek and demand more treatment (37). Taken together, these findings together with reports of a limited effect for this patient group from the treatment modalities conven- tionally used for TMD (38) support the view that TMD after whiplash trauma has a different patophysi- ology compared with localised TMD (29).
It has been suggested that TMD after a whiplash trauma may develop over time, rather than being part of an acute syndrome (29, 39). This notion is based on the fact that most studies in acute whiplash patients report a lower prevalence of TMD pain (28,
Table 1. Papers excluded from the study (n= 26)
Study Reasons for exclusion
Abd-Ul-Salam et al. (54) Not TMD population
Boniver (55) No original data
Burgess (56) Not TMD population
Burgess & Dworkin (57) Not TMD population Burgess et al. (4) Not TMD population
Epstein (58) No original data
Freund & Schwartz (59) Not TMD population Friedman & Weisberg (60) No original data Garcia & Arrington (61) Not TMD population Goldberg et al. (36) Not TMD population Gray & Al-Ani (62) No original data
Greco et al. (63) TMD/trauma groups not defined Huang et al. (64) TMD/trauma groups not defined Kim et al. (65) TMD/trauma groups not defined Kolbinson et al. (37) Not TMD population
Kolbinson et al. (6) Not TMD population Kolbinson et al. (66) Not TMD population Kolbinson et al. (67) Not TMD population Krogstad et al. (68) Not TMD population
Lader (27) No original data
McKay & Christensen (69) No original data
Olin (70) No original data
Pressman et al. (71) Not TMD population Romanelli et al. (72) Not TMD population Seligman & Pullinger (73) Not TMD population Weinberg & Lapointe (25) Not TMD population
Table2.IncludedstudiesreportingtheprevalenceoftraumainpatientswithTMD(n=6) Authors,year Setting/ study designStudysample Subjects(n) (%females) Meanage TMDandwhiplash criteria Prevalenceof trauma Clinicalsignsand symptoms
Quality scoreAuthors’conclusionComments DeBoever& Keersmaekers, 1996
Facialpainunit Caseseries
TMDonly TMD+trauma
n=302 38years n=98 36years
TMD:Helkimosindex Whiplash:self- reportedtraumato head/neck TMDgroup: 245%
Traumagroupmore: severejawpainand dysfunction P<001 limitedjawopening P<001 52%Traumatotheheadand cervicalregionisrelatively commonasaninitiating factorinTMD.External traumatothejointorjawin generalisanimportant initiatingfactorinthe aetiologyofTMD,butthe prognosisisfavourable
Genderofsubjects notgiven Grushkaetal., 2007
Oro-facialpain centre Treatment outcomestudy
TMDonly TMD+trauma
n=82(84%) 39years n=54(80%) 41years RDC/TMD Whiplash:self- reportedtraumato thehead/neck, MVA*
TMDgroup: 397%
Traumagroupmore: headacheP<0002 jawtenderness P<003 stressP=0001 poorsleepP<0001 dizzinessP<0001
65%Widespreadandpersistentpain complaints,includingthejaw inpost-MVA,despitethefact thatmanypost-MVApatients demonstratenoevidenceof jawinjurybybonescanand MRI.Treatmentlimitedtothe TMJsinpost-traumatic patientswithTMDmayfail withoutconsiderationthat painmayoriginatein structuresotherthanthe TMJs
Varyingtimeinterval betweenclinical examinationand MRI/bonescan. Pullinger& Monteiro, 1988
TMD/Oro-facial painclinic Case–control
TMD Allcontrols: Control1 (noTMD) Control2 (mildTMD)
n=152(67%) 18–35years n=331(58%) n=116 18–35years n=215 18–35years TMD:criterianot given Whiplash:self- reportedtrauma tohead/neck
TMDgroup: 304% Control1: 17% Control2: 131%
TMDgroupvs. controls:more traumahistory P<0001 Traumaassociated with:TMDP<0025 headache/cervicalpain P=0001 50%Historyofhead–necktrauma characterisedtheTMDsample comparedwithagematched studentcomparisongroup. StudentswithmildTMD reportedmoretraumathan asymptomaticstudents. Womenseematgreaterrisk ofrespondingadverselyand irreversiblytotrauma UnclearTMD diagnosis. Inaccuraciesinthe Resultssection
Table2.(continued) Authors,year Setting/ study designStudysample Subjects(n) (%females) Meanage TMDandwhiplash criteria Prevalenceof trauma Clinicalsignsand symptoms
Quality scoreAuthors’conclusionComments Pullinger& Seligman, 1991
PrivateTMD clinic Case–control
TMD Control1 (noTMD) Control2 (mildTMD) Control3 (general patients)
n=230 n=61 n=161 n=150
TMD:criterianot given Whiplash:self- reportedMVAor otherhead/neck trauma TMDgroup: 55% Control1:13% Control2:18% Control3:11%
MoretraumainTMD group P<0001 45%PatientswithTMDhavea higherprevalenceoftrauma history.Traumamaybean importantcumulativeand precipitatingfactorinTMD
UnclearTMD diagnosis.Ageand genderofsubjectsnot given.Historyof traumainvestigated differentlyinpatients (personalinterview) andcontrols (questionnaire) Steigerwald etal.1996
PrivateTMD clinic Retrospective TMDn=50(76%) 34years TMD:criterianot given Whiplash:self- reportedtrauma tohead/neck TMDgroup: 70%
Traumagroup:more pain Symptomsimproved afterarthroscopy P=0001
50%Whiplash-inducedTMDmay differfrominsidiousTMDand evenotheronsetofTMDby theprevalenceofneckpain, intensityofneckpainand concurrenceofneckpain, shoulderpain,headache,and jawpain.Thesesymptoms resolvedaftersurgery, indicatingthatTMJpathology wastheperpetutatingforce behind,ifnotthecauseof, thesesymptoms
UnclearTMD diagnosis.No controls. Questionnairefilledin between1and104 weeksaftersurgery Uppgaard, 1992
Privateclinic Caseseries TMDn=382(79%) 10–60+years TMD:criterianot given Whiplash:self- reportedtrauma tohead/neck TMDgroup: 84%
Notclearlyreported20%Successfultreatmentis dependentontheoverall assessmentofthepatient, understandingthepatient’s totalproblemandtreatment options UnclearTMD diagnosis.Nocontrol group.Nomaterial andmethods,or statistics.Resultsnot clearlypresented *MVA,motorvehicleaccident.
40) compared with studies based on chronic WAD patient groups (28, 41–44). When comparing different study populations after whiplash injury, it should also be remembered that a majority with an acute whip- lash injury will recover and that the individuals who develop long-term symptoms report greater initial pain and disability (45). It is therefore reasonable to assume that these individuals are more at risk of developing pain also in the jaw/face region. The development of pain and dysfunction in the jaw region may reflect spread of pain related to close sen- sorimotor linkage between the jaw and neck, as well as lowered sensory and pain thresholds due to central sensitisation. There is support, both in experimental (46–49) and clinical (17) studies of spread and referral of pain between the cervical and trigeminal regions.
Disturbed jaw motor function has been demonstrated after whiplash injury, both in terms of amplitudes and coordination of head and jaw movements and endurance of chewing (50). Furthermore, a recent study shows that experimental pain in the masseter muscle in healthy individuals can affect jaw–neck motor behaviour (51). Taken together, these findings further underline the tight sensorimotor coupling between the jaw and neck regions.
In the present review, using a scoring system modi- fied from MacFarlane (30), the median score for the study quality was 50%. This is comparable with previ- ous studies using the same scoring system to evaluate the prevalence of oro-facial pain (29, 30) reporting median quality scores ranging from 55% to 70%.
However, for the present review, there were consider- able variations between the primary studies, not only in the study quality scores, but also with regard to study populations, methodology, and criteria for TMD diagnosis. To improve the diagnosis of TMD, the research diagnostic criteria/temporomandibular disor- ders (RDC/TMDs) were introduced in 1992 (2) and are now widely used by clinicians and researchers. In the present systematic review, most of the primary studies were carried out before 1992 and only one study (31) used these criteria, which have a proven reliability and validity for the diagnosis of TMD (52).
A new evidence-based DC/TMD protocol for use in both clinical and research setting has recently been developed (53). The new DC/TMD is an important step towards the goal of developing a mechanism- and aetiology-based DC/TMD that will more accu- rately direct the clinicians in providing personalised
care for their patients. In the present review, there were also uncertainties with regard to the history of whiplash trauma, as these data were collected with different methods, for example questionnaires versus personal interviews, and for all studies, were based on patients’ self-reports. Only two of the studies included control groups without TMD (32, 33). All these limi- tations need to be taken into account as it makes it difficult to draw firm conclusions from the present review. More well-designed studies on the develop- ment of TMD after whiplash trauma using the DC/
TMD criteria in epidemiological population-based studies are needed.
The results from the present review have implica- tions for assessment of patients with TMD. Examina- tion of these patients should include the neck region, which could provide a more individualised rehabilita- tion regimen. A multidisciplinary rehabilitation pro- gramme should be advocated in TMD patients with whiplash-related neck pain. As the aetiology for TMD is multifactorial, further studies on the mechanisms of the association between whiplash trauma and TMD, and to what extent a neck injury can contribute to the development of TMD, are warranted.
Conclusions
In conclusion, the prevalence of whiplash trauma is higher in patients with TMD compared with controls.
In addition, the data suggest that TMD patients with comorbid TMD/whiplash have more jaw pain and more severe jaw dysfunction, compared with TMD patients without a history of neck injury. These results suggest that whiplash trauma might be an ini- tiating and/or aggravating factor as well as a comorbid condition for TMD.
Disclosures
The authors report no conflict of interest declared.
This investigation was carried out without funding.
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Correspondence: B. H€aggman-Henrikson, Department of Odontol- ogy/Clinical Oral Physiology, Umea University, Umea SE-901 87, Sweden. E-mail: birgitta.henrikson@odont.umu.se
