Investigating the relationship between temporomandibular disorders and personality traits

1. Introduction

Temporomandibular disorders (TMD) are complex clinical conditions characterized by orofacial pain, joint dysfunction and muscular impairments, significantly impacting patients’ quality of life. It is one of the main causes of chronic non-odontogenic pain in the general population and can be associated with functional limitations, masticatory difficulties, and sleep disturbances, thus negatively influencing the psychophysical well-being of the individual [1]. Scientific literature has widely demonstrated the influence of psychological factors, such as stress and negative emotions, on pain perception in TMD [2, 3, 4]. Stressful life events, anxiety and depressive traits have been identified as triggers, aggravators, and perpetuators of symptoms, also affecting treatment responses [5, 6, 7]. These findings highlight the need for a multidimensional approach in evaluating and managing TMD. While the role of emotions in chronic pain modulation is well-established, few studies have specifically explored the correlation between TMD and personality disorder conditions marked by dysfunctional emotional regulation, affective instability and interpersonal difficulties [8]. Personality disorders are often associated with heightened emotional dysregulation, which may influence the central pain process. Emerging evidence suggests that individuals with dysfunctional personality traits may exhibit lower pain thresholds, increased sensitivity to nociceptive stimuli, and a tendency toward pain catastrophizing, potentially contributing to TMD symptom chronicity [9, 10, 11]. However, the relationship between personality traits and TMD remains understudied.

This study aims to investigate the association between dysfunctional personality traits and TMD symptoms, filling a gap in the current literature. Through a multidisciplinary analysis integrating dental and psychological assessments, this research explores the potential impact of personality traits on pain perception, symptom severity and clinical management. Identifying such correlations may offer new insights for targeted, personalized therapeutic approaches, ultimately improving the quality of life for TMD patients [12].

2. Materials and methods

The present study is an analytical observational case-control design conducted over 1.5 years between April 2023 and October 2024 at the Operative Unit of Odontostomatology of ASST Santi Paolo e Carlo, directed by Professor Andrea Sardella. The case group included symptomatic TMD patients recruited from the Gnathology department of the G. Vogel Dental Clinic on Via Beldiletto, while the control group comprised individuals not affiliated with this department. Both groups were administered the Personality Inventory for Diagnostic and statistical manual of mental disorders (DSM)-5-Brief Form (PID-5-BF) questionnaire to assess the prevalence of potential personality dysfunctions or specific personality domains. All subjects participating in the research signed a written or digital consent.

3. Results

The questionnaire scores were analyzed as previously described by a single examiner. After confirming compatibility with general population norms by comparing results to normalized T-scores, statistical analysis was performed (Table 1). The p-values indicate that the data does not follow a normal distribution, consistent with the nature of introspective analyses of individual emotions and perceptions, where conflicts between self-perception and social conformity may emerge. Comparison with standardized T-scores revealed no deviations from normative values, suggesting no significant personality disorder prevalence in the sample. However, differences between cases and controls were observed.

We analyzed the Independent Samples Test in Table 2: a statistically significant difference was found between case and control groups for total raw score (p: 0.016), mean total score (p: 0.016), and the domains of negative affectivity (p: 0.017), detachment (p: 0.052), and antagonism (p: 0.012). No significant differences were observed for disinhibition or psychoticism.

The case group exhibited higher scores than the control group in total raw score, mean total score, negative affectivity, detachment and antagonism (Table 3).

Table 4 shows the Non-Parametric Mann-Whitney Test. Consistent with prior results, the case group showed statistically significant differences in mean total score (p: 0.021), negative affectivity (p: 0.024), and antagonism (p: 0.039). Detachment differences, however, were marginally significant (p = 0.094), suggesting low-level significance.

Age- and sex-stratified analyses revealed no statistically significant differences.

4. Discussion

This study explored the correlation between temporomandibular disorders (TMD) and personality traits, focusing on psychological and somatic factors influencing symptom onset and chronicity. While T-scores aligned with normative data, deeper analysis revealed higher personality dysfunction in TMD patients, particularly in negative affectivity and antagonism. These traits marked by intense negative emotions, hostility and relational difficulties may perpetuate pain by amplifying emotional dysregulation. Emotional dysregulation is hypothesized to alter pain perception, contributing to TMD onset and chronicity [20, 21]. Negative affectivity and chronic stress may act as risk factors, especially in patients without global somatic symptoms [22, 23]. Emerging evidence suggests that unrecognized or mismanaged emotions exacerbate pain perception [24], highlighting the role of emotional regulation in TMD prevention and treatment [25, 26]. The results suggest that emotions influence pain perception in patients, independently of the presence of a personality disorder. However in these subjects, emotional dysregulation is intrinsic, so the removal of stressogenic factors might not be sufficient to alleviate symptomatology. Several studies support the importance of psychological aspects in pain management, highlighting the efficacy of Pain Neuroscience Education (PNE) in musculoskeletal pain management [27]. This educational approach uses metaphors and visuals to reframe pain neurobiology, reduce fear, and correct structural misconceptions [28, 29, 30]. Cognitive-Behavioral Therapy (CBT) has also proven effective in treating TMD; it teaches stress management and emotional regulation strategies, thus reducing pain impact and muscle activity in TMD [31]. In conclusion, the study highlights the relevance of psychological and personality factors in the treatment of TMD. Further research is necessary to clarify the role of negative emotions, stress and emotional dysregulation in the chronicization of symptoms, but current data suggest that integrating psychological approaches into therapeutic protocols could significantly improve clinical outcomes.

It is essential to consider the limitations of this study: a significant obstacle is the difficulty in completely isolating confounding variables (e.g., sociodemographics, lifestyle, preexisting conditions). The use of a brief questionnaire, while pragmatic, might have limited some relevant details. Furthermore, emotional and psychological data are inherently influenced by social context, health, and life experiences, thereby complicating TMD correlation analyses. Larger samples and more detailed assessment tools could enhance validity and further clarify the complexity of the relationship between psychological factors and TMD.

5. Conclusions

These findings underscore the importance of integrating psychological and physical approaches in TMD management. Recognizing emotional components as key factors enables the inclusion of therapies like cognitive-behavoral therapy alongside traditional gnathological treatments, thereby improving symptom relief, stress management and emotional regulation. A holistic, multidisciplinary framework may optimize clinical outcomes and patient well-being and may be inspiration for future research on psychological factors in TMD chronicity.

Abbreviations

TMD, Temporomandibular Disorder; CBT, Cognitive Behavioral Therapy; PNE, Pain Neuroscience Education; DSM, Diagnostic and statistical manual of mental disorders; PID-5-BF, Personality Inventory for DSM-5-Brief Form.

Availability of data and materials

Data is available by corresponding email: alessandro.marchesi@unimi.it.

Author contributions

AM—the conception of the manuscript, the acquisition of the data, the analysis and interpretation of the statistical data and the processing of the manuscript. RB and AS—the acquisition of the data, the analysis and interpretation of the statistical data and the processing of the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

The study was carried out following the Helsinki Declaration on Human Clinical Research. The authors confirm that the Ethics Committee of University of Milan is aware of the work carried out. Nevertheless, written approval from Committee was not considered necessary and therefore not requested given the fact that the procedures applied in this study were observational only and did not include treatment of the patient. All subjects participating in the research signed a written or digital consent.

Acknowledgment

Not applicable.

Funding

This research received no external funding.

Conflict of interest

The authors certify that there are no conflicts of interest with any financial organization with reference to the material discussed in the manuscript.