Temporomandibular Disorders: Prevalence and Associated Biopsychosocial Factors

An Analysis of Data From the NAKO Health Study

Background: “Temporomandibular disorders” (TMD) is an umbrella term for symptoms in the area of the temporomandibular joints and muscles of mastication. TMD constitute one of the more common types of musculoskeletal pain. Previous estimates of the prevalence of TMD suffered from methodological limitations. The NAKO Health Study enables, for the first time, an examination-based estimate of the prevalence of painful TMD in a large population sample.

Methods: The baseline survey (2014–2019) was carried out in a partial population sample and involved standardized examinations of jaw mobility and palpation of the muscles of mastication. Painful TMD was recorded when a positive pain history was combined with pain that could be localized and induced on examination. Crude and adjusted prevalences were calculated, and associations with putative etiological and associated factors were analyzed by logistic regression.

Results: Of the 20 603 participants, 10.9% reported jaw or facial pain in the preceding month. The point prevalence of painful TMD was 3.7% overall and 6% among persons aged 20–29. TMD was more common in women, with an odds ratio of 2.72 (95% confidence interval: [2.28; 3.25]), as well as in smokers (1.42 [1.16; 1.74]) and in participants reporting sleep disturbances (1.96 [1.6; 2.4]), childhood trauma (1.11 [1.08; 1.14] per scale point), anxiety (1.12 [1.09; 1.14] per scale point), or depression (1.11 [1.09; 1.13] per scale point). Orthodontic treatment before the age of 19 did not increase or decrease the likelihood of painful TMD. Abnormal tooth and jaw positions were associated with a lower prevalence.

Conclusion: Painful TMD is a common health problem that is not associated with dental morphological abnormalities, but rather with various biopsychosocial factors. These findings underscore the need for interdisciplinary diagnosis and treatment.

Cite this as: Herpel C, Becher H, Aarabi G, Borof K, Castell S, Ciardo A, Finke H, Hellmann D, Hertrampf K, Holtfreter B, Karch A, Keil T, Kemmling Y, Kim TS, Leitzmann M, Pischon N, Pischon T, Reckelkamm S, Rupf S, Rütters M, Samietz S, Schipf S, Schmitter M, Schulze MB, Schwindling S, Schwichtenberg J, Tesarz J, Völzke H, Willich SN, Rammelsberg P: Temporomandibular disorders: Prevalence and associated biopsychosocial factors. An analysis of data from the NAKO Health Study. Dtsch Arztebl Int 2026; 123: 63–70. DOI: 10.3238/arztebl.m2025.0219

The umbrella term “temporomandibular disorders” (TMD) has evolved over time to refer to the most common musculoskeletal complaints in the temporomandibular and facial region. These disorders are characterized by restricted movement and function-related pain in the temporomandibular joints or muscles of mastication. This may involve both primary/idiopathic pain and secondary/symptomatic disorders arising from temporomandibular joint pathology (1, 2). The term more commonly used in German-speaking countries, “craniomandibular dysfunction” (CMD), includes disorders attributable to occlusion (3). Many individuals with TMD experience significant pain and psychosocial burden, and the pain may persist for many years (4). In a longitudinal study, only about one third of patients exhibited a sustained reduction in symptoms within 5 years. Another third experienced recurrent or persistent pain (5). In a cross-sectional study, one third of individuals with chronic painful TMD experienced severe limitations in work and daily activities (6). TMD often presents not as a regionally confined pain disorder but as a combination of several comorbid, overlapping pain syndromes (7).

Prevalence estimates to date are largely based on self-reported pain in the temporomandibular or facial regions (8). This is unreliable, since many other disorders can cause non-dentogenic orofacial pain (9). For the prevalence of painful TMD based on clinical criteria, the largest available studies reported estimates of 2.8% (N = 895 [10]), 14% (N = 241 [11]), and 29.5% for myalgia (N = 1643 [12]). Thus, these estimates were, at times, in marked disagreement with questionnaire-based surveys. They showed significant inconsistencies, were based on smaller samples, and are therefore not informative (13).

As part of the NAKO baseline survey, a comprehensive dental examination was conducted in a subsample, thereby enabling, for the first time, an examination-based prevalence estimate for painful TMD in a large, population-based cohort. In addition, multiple potential influencing factors were assessed. Although morphological factors such as jaw and dental misalignment were long regarded as principal causes, our understanding of TMD has gradually evolved toward a multifactorial biopsychosocial disease model that takes into account the complex interplay between biological, psychological, and social factors (7, 14).

The aim of this study was to determine the prevalence of painful TMD in the baseline survey and to analyze its relationship with dental and biopsychosocial influencing factors.

Methods

Study design

The German NAKO (Nationale Kohorte) Health Study is a longitudinal, multicenter cohort study with approximately 200 000 participants at 18 different study centers across Germany (15). Participants underwent comprehensive medical examinations and questionnaires (Level-1 examination). A subgroup additionally underwent a thorough oral and dental examination (Level-2 examination) (16, 17).

Examinations

A more detailed description of the dental examination (18) and the variables analyzed can be found in the eSupplement. The sociodemographic variables analyzed included sex, age group, migration background, and socioeconomic status.

A diagnosis of “painful TMD” (pTMD) was made if temporomandibular arthralgia or myofascial orofacial pain was present. Prerequisites included a history of orofacial pain and pain elicited by maximal mouth opening or by palpation of the masticatory muscles using a pressure algometer (4.5 N).

Dental variables included overjet (horizontal distance between corresponding incisal edges) and overbite (vertical distance), each classified into five groups (0 mm, 0–1 mm, 2–3 mm, 4–5 mm, > 5 mm), with 2–3 mm considered the normal range (19). Loss of posterior support in the molar region was assumed if, on at least one side, all molars in a jaw (maxilla or mandible) were missing and had not been replaced. Since only one side of the jaw was examined, it was possible to distinguish between “confirmed absence” and “possible absence” of posterior support. Orthodontic treatment was classified as “none,” “completed before age 18,” “completed after age 18,” or “ongoing.” Dental prostheses were categorized as “removable prostheses in one jaw,” “in both jaws,” or “no removable prostheses.”

All potentially associated and confounding variables were selected a priori based on the existing literature on TMD. This selection was limited by the quality-assured data available at the time the data access application was submitted as part of the NAKO Health Study. The lifestyle factors considered included physical activity (meeting WHO recommendations, yes/no) and current smoking status (smoker, yes/no). Other parameters recorded included sleep quality (sleep initiation or maintenance disorders or early awakening and subjectively poor sleep at least three times per week, yes/no), depression (PHQ-9, 0–27), anxiety (GAD-7, 0–21), childhood trauma (Childhood Trauma Screener, 5–25), and social integration (abbreviated Social Network Index).

Statistical analysis

The prevalence of painful TMD was calculated as a simple proportion as well as taking center-specific weighting factors into consideration. The weighting factors capture age and socioeconomic status (education) in addition to the design-specific age distribution of the total study population (20), thereby enabling an approximately representative estimate of population prevalence. A complete-case analysis was performed as the primary analysis (21). The association between TMD (yes/no) with dental variables and the other abovementioned factors was examined with logistic regression. For each variable, two different regression models were calculated. Model 1 was adjusted for the (socio-)demographic variables age, sex, study center, migrant background, and socioeconomic status. Model 2 describes the multivariable association with TMD in a comprehensive model of all variables. Data analyses were performed using SPSS version 29.

Results

Study results and demographic variables

Between 2014 and 2019, a total of 20 603 (9831 females, 10 772 males) aged between 20 and 73 years participated in the Level-2 baseline dental survey at 14 of the 18 study centers. The mean age was 49.9 years in women and 49.5 years in men. A total of 10.1% of participants reported jaw or facial pain in the preceding month. Maximal mouth opening elicited pain in 15.1% and palpation of the masticatory muscles in 2.7% of participants. The combination of a positive pain history and pain elicitation required for the diagnosis of painful TMD was met by 2.9% (95% confidence interval: [2.7; 3.2] (Table 1, eTable, eFigure). Using the correction weights, the prevalence increased by approximately 30% to 3.7% [3.4; 4.0]. The Figure shows the prevalence of facial pain (based on patient history) and painful TMD by sex and age group. Overall, the adjusted prevalence was highest in the 20–29 age group (6%) and declined steadily with increasing age. Women were significantly more frequently affected (5.5%) compared to men (2%; odds ratio [OR] 2.72; [2.28; 3.25]; p <0.001). Individuals with a migrant background and lower socioeconomic status also had a higher prevalence (Table 2).

Figure

Weighted prevalences of purely self-reported jaw or facial pain (1-month prevalences) as well as painful TMD based on clinical examination (point prevalences) in the different age groups in the baseline survey of the NAKO Health Study

Table 1

Prevalence of jaw or facial pain and of the diagnostic criteria for painful temporomandibular disorders

Table 2

Unweighted prevalence of painful TMD and its distribution by demographic variables in the NAKO Health Study

eFigure

Distribution of pain diagnoses by lateralization and location.

eTable

Number of participants and prevalence of painful temporomandibular disorders (unweighted) by study center

Associations with dental variables

Overjet and overbite values deviating from the reference range (2–3 mm) were each associated with a tendency toward lower prevalence (Table 3). Confirmed loss of posterior tooth support was found in 1049 participants (5.1%) following unilateral occlusal examination. After adjustment for age, sex, and demographic variables (Model 1), confirmed loss of posterior tooth support had no effect on the prevalence of painful TMD. In cases of orthodontic treatment after the age of 18 or ongoing treatment, the OR was increased (reference: no orthodontic treatment). For removable dental prostheses, an increased OR was only observed for dental prostheses in one jaw. In the combined regression model (Model 2), orthodontic treatment completed after age 18 was positively associated with TMD, while an overjet >5 mm was inversely associated with TMD.

Table 3

Association between dental variables and the prevalence of painful temporomandibular disorders in the NAKO Health Study

Associations with biopsychosocial factors

After adjusting for all demographic variables (Model 1), all investigated biopsychosocial variables (smoking, poor sleep quality, low social integration, depression, anxiety, childhood trauma), with the exception of physical inactivity, were associated with the presence of painful TMD. When all variables were included in an exploratory, combined model (Model 2), anxiety symptoms, depression, childhood trauma, and poor sleep quality in particular remained associated with an increased OR (Table 4).

Table 4

Association between dental variables and the prevalence of painful temporomandibular disorders in the NAKO Health Study

Discussion

The NAKO Health Study provides, for the first time, clinically standardized prevalence data on painful TMD in a large population sample. Compared with earlier, purely questionnaire-based studies that reported a higher prevalence, data from the NAKO Health Study yield a closer estimate of the actual disease burden. All biopsychosocial factors considered, with the exception of physical inactivity, were associated with a higher prevalence.

The unadjusted point prevalence of painful TMD was 2.9%, with young adults (20–29 years) representing the most frequently affected group (5.1%). Adjustment using the correction weights from Rach et al. (20) increased the estimate to 3.7% and 6.0%, respectively. Women had an OR of 2.7. The correction weights developed in Rach et al. are suitable for an adjusted estimation with respect to age and social structure, assuming the entire NAKO study population is considered. Therefore, they are only of limited suitability for the present subsample analysis. We present selected adjusted estimates, since we can assume a similar distribution with regard to age and social structure. In the literature, prevalence estimates of jaw or facial pain based purely on self-reported symptoms range from 6.3% to 15% in women and from 3.2% to 10% in men, with point and 6-month prevalences being assessed in some cases (8). The ratio of women to men varied between 1.4: 1 and 2.6: 1. The US National Health Interview Surveys (NHIS) reported a 6-month prevalence of 6.7% (8.8% women; 4.4% men; N = 42 370) in 1989 (22) and a 3-month prevalence of 4.6% (6.3% women; 2.8% men; N = 30 978) in 2002 (23). Thus, in comparison, the prevalence rates in the NAKO baseline survey are at the lower end of the data reported in the literature. Prevalences based on a clinical examination have thus far only been available from smaller, poorly representative samples. A systematic review (six studies, N = 2491) estimated myofascial pain of the masticatory muscles at 9.7% and temporomandibular joint arthralgia at 2.6%. All investigations were based on validated diagnostic criteria, but varied significantly (13). The largest included sample, also from Germany, reported a prevalence of 2.8% (myalgia or arthralgia, N = 895) (10). Since the examination-based prevalence estimate for painful TMD was approximately one-third of the 1-month self-reported prevalence, a relevant proportion of self-reported jaw or facial pain may not have a musculoskeletal etiology or may occur only intermittently. However, the comparability of prevalence estimates is limited, since the individual estimates are not age-adjusted.

Deviations in overjet or overbite and missing posterior tooth support were previously considered risk factors for TMD and served as the basis for preventive or curative orthodontic or prosthetic treatment (e12, e13). Currently, the prevailing view is that there are insufficient data to support this (14, 19) (e14, e15, e16). Consistent with this, orthodontic treatment before the age of 19 was not associated with reduced odds of TMD pain. Prosthetic treatment is likewise not considered a relevant risk factor in the literature, although the evidence for both treatments is limited (24, 25, 26).

The findings of the NAKO Health Study support the move away from older paradigms, but paint a more nuanced picture. The fact that deviations in overbite or overjet were even associated with a lower prevalence is a new finding that will need to be confirmed in follow-up NAKO studies or future cohort studies. There does not appear to be any evidence to date to suggest a causal link.

The fact that only a single removable prosthesis was associated with an increased risk is consistent with studies on oral health-related quality of life: These show that certain dental prosthetic and tooth-loss patterns are associated, to varying degrees, with oral impacts on daily performance. The use of complete dentures in both jaws appears to be associated with a lower oral impact (27). The fact that orthodontic treatment after the age of 18 was associated with higher odds of painful TMD may be attributable to outdated therapeutic approaches in adult treatment. It is possible that a relevant proportion of individuals with painful TMD undergo orthodontic treatment in the hope that their symptoms will improve. Treatments of this kind are still widespread in Germany today, despite the complete lack of reliable evidence for such interventions (28).

The spectrum of TMD includes, among other conditions, temporomandibular joint disorders that are predominantly caused by displacement of the articular disc. In most affected individuals, these conditions are generally self-limiting and usually do not require specific treatment. Even when permanent changes to joint mechanics remain, the associated pain is typically only temporary. However, in a large proportion of individuals with TMD, symptoms take the form of a chronic pain syndrome. As with other pain disorders, a variety of biopsychosocial contributing factors have been identified for this pain (29). All variables investigated here (with the exception of physical inactivity) were associated with a higher odds ratio for painful TMD. The weak effect sizes are consistent with the evidence for many musculoskeletal pain disorders. Rather than individual dominant predictors, a multifactorial etiology with numerous contributing factors, each having only a small individual effect, has been described (30). In addition, the relevance of psychosocial factors varies in the subgroups: TMD pain affects patients with primary chronic pain as well as those with secondary, structurally mediated pain. The latter show a lower psychosocial burden profile despite comparable functional limitations and sometimes long disease courses, and less frequently meet the stricter criteria for chronic pain (31).

The effect of psychological stress, for which an association with TMD pain has also been demonstrated, was not explicitly taken into consideration, although relevant overlap with the constructs of anxiety and depression can be assumed. Data on bruxism or previous trauma were not collected in the NAKO Health Study. According to current evidence, orofacial trauma plays only a minor role in the etiology of TMD (32). The association with bruxism has not been convincingly demonstrated to date; robust evidence is lacking, particularly for awake bruxism, and polysomnography in cross-sectional studies failed to show an association for sleep bruxism. Longitudinal studies of high methodological quality are still lacking (33).

In the combined model, the effects of low social integration, smoking, and poor sleep quality were attenuated, which is attributable to positive correlations between these variables. All variables investigated—with the exception of childhood trauma burden—can be both a cause and a consequence of chronic pain. Thus, the findings of the NAKO provide important confirmation regarding which comorbidities in individuals with painful TMD frequently require co-management and which factors may constitute targets for therapeutic interventions. Many individuals will benefit from improved sleep, greater social integration, and psychotherapeutic support for pain (34, 35, 36). Physical activity is a key component in the treatment of chronic pain, including TMD (37, 38).

This analysis was based on the WHO minimum criteria and relied on self-reports, thereby capturing only a basic measure. The proportion of missing values was moderate, allowing a complete-case analysis to be performed. Multiple imputation was additionally conducted and yielded no significant differences in the results (data not shown). A unique feature of the NAKO data is that painful TMD could be determined by clinical examination. All examiners were trained to conduct standardized examinations (18). However, a complete examination protocol conforming to the gold standard of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) was not used (39). The history-based criterion of pain influenced by jaw function and the agreement between clinically provoked and self-reported pain (“known pain” criterion) were not assessed. The examination largely corresponded to the brief DC/TMD, particularly with regard to limiting it to jaw opening movements and palpation of the masseter and temporalis muscles (40).

Summary

The results of the baseline survey of the NAKO Health Study provide the best evidence available to date on the prevalence of painful TMD. Anomalies in tooth and jaw positions tend to be associated with a lower prevalence. In contrast, therapeutic dental interventions appear to pose a risk. Various biopsychosocial factors, in particular psychological distress and sleep problems, play a crucial role. These findings support a paradigm shift toward multifactorial explanatory models and underscore the need for interdisciplinary diagnosis and treatment.

Additional contributing authors
Ghazal Aarabi, Katrin Borof, Stefanie Castell, Antonio Ciardo, Hannah Finke, Daniel Hellmann, Katrin Hertrampf, Birte Holtfreter, André Karch, Thomas Keil, Yvonne Kemmling, Ti-Sun Kim, Michael Leitzmann, Nicole Pischon, Tobias Pischon, Stefan Reckelkamm, Stefan Rupf, Maurice Rütters, Stefanie Samietz, Sabine Schipf, Marc Schmitter; Matthias B. Schulze, Sebastian Schwindling, Julia Schwichtenberg, Jonas Tesarz, Henry Völzke, Stefan N. Willich

Funding
This project was conducted using data from the NAKO Health Study (Gesundheitsstudie; data access application No. NAKO-937) (www.nako.de). The NAKO Health Study is funded by the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) (Grant Nos. 01ER1301A/B/C, 01ER1511D, 01ER1801A/B/C/D, and 01ER2301A/B/C), the German federal states, and the Helmholtz Association, and receives financial support from the participating universities and institutes of the Leibniz Association. We would like to thank all participants and staff of the NAKO Health Study.

The research was also funded by the Clinician Scientist Program of the Medical Faculty of Heidelberg University, Germany.

Artificial intelligence
Artificial intelligence (GPT-4o, OpenAI) was used solely for language editing of selected text passages. It was not used for content development, text structuring, or data analysis.

Conflict of interest statement

André Karch is a member of the Scientific Council of the International Agency for Research on Cancer (IARC).

Tobias Pischon is an honorary member of the Executive Board of NAKO e.V., which heads the NAKO Health Study.

Stefan Rupf is Head of the Expert Group “Dental Medicine” (“Zahnmedizin”) of the NAKO Health Study.

Jonas Tesarz received travel cost reimbursement from the German Federal Ministry of Education and Research (BMBF) and the following specialist societies in the field of psychosomatic medicine and pain therapy: IGPS, EMDRIA, and DGSS. He received study support (third-party funding) from the German Research Foundation (DFG) and the BMBF.

The remaining authors declare that no conflict of interest exists.

Manuscript submitted on 2 August 2025, revised version accepted on 19 November 2025.

Translated from the original German by Christine Rye.

Corresponding author
PD Dr. med. dent. Christopher Herpel

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