Painful Temporomandibular Disorder

Abstract

In 2006, the OPPERA project (Orofacial Pain: Prospective Evaluation and Risk Assessment) set out to identify risk factors for development of painful temporomandibular disorder (TMD). A decade later, this review summarizes its key findings. At 4 US study sites, OPPERA recruited and examined 3,258 community-based TMD-free adults assessing genetic and phenotypic measures of biological, psychosocial, clinical, and health status characteristics. During follow-up, 4% of participants per annum developed clinically verified TMD, although that was a "symptom iceberg" when compared with the 19% annual rate of facial pain symptoms. The most influential predictors of clinical TMD were simple checklists of comorbid health conditions and nonpainful orofacial symptoms. Self-reports of jaw parafunction were markedly stronger predictors than corresponding examiner assessments. The strongest psychosocial predictor was frequency of somatic symptoms, although not somatic reactivity. Pressure pain thresholds measured at cranial sites only weakly predicted incident TMD yet were strongly associated with chronic TMD, cross-sectionally, in OPPERA's separate case-control study. The puzzle was resolved in OPPERA's nested case-control study where repeated measures of pressure pain thresholds revealed fluctuation that coincided with TMD's onset, persistence, and recovery but did not predict its incidence. The nested case-control study likewise furnished novel evidence that deteriorating sleep quality predicted TMD incidence. Three hundred genes were investigated, implicating 6 single-nucleotide polymorphisms (SNPs) as risk factors for chronic TMD, while another 6 SNPs were associated with intermediate phenotypes for TMD. One study identified a serotonergic pathway in which multiple SNPs influenced risk of chronic TMD. Two other studies investigating gene-environment interactions found that effects of stress on pain were modified by variation in the gene encoding catechol O-methyltransferase. Lessons learned from OPPERA have verified some implicated risk factors for TMD and refuted others, redirecting our thinking. Now it is time to apply those lessons to studies investigating treatment and prevention of TMD.

Premorbid and concurrent predictors of TMD onset and persistence

“…Indeed, in contrast to many other major diseases in which common immutable factors (gender, age, race) have substantial contributions, we note that for acute TMD the major predictor (3) thin solid arrows that indicate contributions from the stated factors into potential disease onset, transition or chronicity; (4) fat solid arrows that indicate the state shift from premorbid to acute, to transition state and to chronic state; and (5) the specific identification of disease-related person characteristics (DRPC)-particular aspects of the 'person' attached to each phase of the pain disorder, in order to emphasize that the disorder exists not alone but in the context of a person-state related to that disorder at that phase. This model builds on previously published work; see Slade et al, 2016) for summaries and results related to identified nodes in the Figure. In addition, the model extends into the post-onset period, thereby suggesting hypothesized patterns of interaction across time with moderating and mediating variables. Premorbid factors are comprised of: person-level variables of problems with stress and coping, psychological distress, general body tenderness, anxiety, impaired sleep, functional symptoms, other pain disorders, and pain sensitivity.…”

Facial Pain: A Comprehensive Review and Proposal for a Pragmatic Diagnostic Approach

“…Indeed, TMD are often associated with, for example, mood disorders. Other risk factors are bruxism, certain genetic factors, migraine, tension-type headache, other chronic pain conditions, and a history of trauma, as described in the longitudinal OP-PERA study [71][72][73][74][75]. Whether an aberrant dental occlusion is a risk factor for TMD is still debated, although the existing evidence shows no clear-cut association between TMD symptoms or signs and malocclusion [76,77].…”

Protein Signature in Saliva of Temporomandibular Disorders Myalgia

“…Temporomandibular disorders (TMD) are a cluster of conditions that cause pain and dysfunction in the temporomandibular joint, masticatory muscles, and surrounding structures, e.g., ligaments and connective tissues [1,2]. It causes high suffering to those affected in the community and is a widespread problem in clinical practice [2][3][4][5]. TMD affects 10-15% of the adult population and seems to be three times more frequent in women [1,2].…”