Temporomandibular Joint Disorders and Mental Health: Unleashing the Veiled Bond

Escalating Incidence of Temporomandibular Joint Disorders

TMD symptoms can occur across a wide age range and are relatively common among children and adolescents. The prevalence of temporomandibular joint and muscle disorders (TMJD) is estimated to be between 5% and 12%, with some studies reporting higher rates, reaching up to 25% and even 33% to 40% in the general population.^[7] However, TMDs are more commonly observed in young and middle-aged adults, with peak occurrence between 20 and 40 years of age. The condition is at least twice as prevalent in women compared to men.^[8] TMD is associated with substantial morbidity, affecting quality of life and work productivity. Its prevalence in India varies widely, ranging from 18% to 61.2%, depending on the population and assessment methods. Studies indicate that females exhibit higher levels of stress and parafunctional habits compared to males, both of which are significant contributing factors to TMDs. Females in their reproductive years (ages 20–40) are at higher risk, likely due to hormonal and psychosocial factors. Further large-scale, population-based studies in India are needed to accurately determine the incidence of TMDs.

TMD’s Foreshadowing Mental Health Disorders

Pain around the temporomandibular joint can result from disorders within the joint itself, issues in nearby structures, or a combination of both.^[9] TMDs can also present with symptoms beyond the musculoskeletal system, including tinnitus, referred ear pain, headaches (such as tension headaches or migraines), toothaches, neck pain, and myofascial pain. According to a report by the World Health Organization (WHO), TMDs are the third-most prevalent stomatological condition, following dental caries and periodontal diseases.^[10]

The causes of TMD include biological, environmental (such as smoking), emotional (like depression and anxiety), social, and cognitive factors. It is frequently associated with other pain conditions, such as chronic headaches, fibromyalgia, autoimmune diseases (including Sjogren’s syndrome, rheumatoid arthritis, and lupus erythematosus), psychiatric disorders, and sleep apnea.^[11] There is a growing association between TMD symptoms and psychological factors, such as depression, anxiety, and oral parafunctional habits, particularly bruxism, in adolescents. Poor sleep quality and high stress levels are emerging as key contributing factors. Individuals with TMDs are more frequently affected by anxiety and depression compared to the general population.^[12] TMD pain has an inimical impact on the mood and mental health of patients. Mental health includes psychological, emotional, and social well-being, shaping how we think, feel, and act. It is essential for managing stress, fostering relationships, and making decisions. Mental health remains crucial at every stage of life, from childhood through adulthood. It is influenced by environmental factors and nutritional status, which reflects how dietary habits and choices fulfill an individual’s nutritional needs.^[13] Being deprived of one’s favorite foods and needing to substitute these with less satisfying food due to difficulty in chewing and eating, a grave feeling of depression and pessimism may occur.^[14] Unfortunately, healthcare providers often fail to recognize the full scope of mental distress experienced by these patients. Their focus is usually on the medical aspects of treatment, neglecting the emotional, functional, and social factors that contribute to the patients’ overall suffering.

Bidirectional Relationship between TMD and Mental health issues

TMD and mental health are closely interconnected. Research^[15] highlights a bidirectional relationship between TMD and various mental health issues, such as anxiety, depression, and stress. Psychological stress often triggers muscle tension, especially in the jaw, neck, and face. Over time, this tension can lead to teeth grinding (bruxism), clenching, or abnormal jaw movement, contributing to TMD. Depression can reduce pain tolerance and increase perception of pain, making symptoms of TMD feel more intense. It may also contribute to fatigue and poor posture, exacerbating TMD symptoms. Individuals suffering from anxiety or post-traumatic stress disorder (PTSD) may exhibit behaviors such as clenching or jaw-tightening as a response to emotional distress, putting pressure on the temporomandibular joint. A patient with TMD often exhibits central sensitization, where the nervous system tends to become overly sensitive to pain stimuli. This is also seen in conditions like fibromyalgia and depression.^[16] Dysregulation of neurotransmitters like serotonin, dopamine, and cortisol is common in both mental health disorders and chronic pain conditions like TMD. Chronic pain in TMD is associated with the sensitization of supraspinal and second-order neurons within the dorsal horn and subnucleus caudalis of the trigeminal spinal nucleus. This condition is further influenced by an imbalance in antinociceptive mechanisms and a significant genetic predisposition.^[17] The pain associated with TMD may trigger these mental disorders; both TMD and mental health disorders experienced by patients with anxiety and depression are associated with heightened stress responses, including activation of the hypothalamic-pituitary-adrenal (HPA) axis, which in turn increases the cortisol levels. Stress can lead to parafunctional habits such as bruxism (teeth grinding), which exacerbates TMD.^[18] It has been perceived that both TMD and mental health disorders involve central sensitization, where the nervous system becomes hypersensitive to stimuli, amplifying pain perception. This mechanism is common in conditions like fibromyalgia, migraines, and other chronic pain syndromes, which often coexist with TMD.^[19] Chronic stress and emotional dysregulation may increase neuroinflammatory processes, which are implicated in both chronic pain conditions and mental health disorders.^[20] Altered serotonin and dopamine pathways are implicated in both mental health conditions (e.g., depression, anxiety) and TMD-related pain processing.^[21] The link between mental and oral health has been explored through biological and behavioral mechanisms. The connection between oral health and depression is complex, involving a variety of biological, psychological, and social factors, making it difficult to identify precise mechanisms.