TMJ

Temporomandibular Disorders (TMD / TMJ): A Natural-Health and Nutritional Reference

1. Definition and Nomenclature

Temporomandibular disorders (TMDs) are a group of more than 30 conditions that cause pain and dysfunction in the jaw joint and muscles that control jaw movement. "TMDs" refers to the disorders, while "TMJ" refers only to the temporomandibular joint itself. In common usage, "TMJ" is widely employed as shorthand for the full spectrum of these conditions, and that convention is followed throughout this article.

The term temporomandibular disorders is an umbrella term for a group of musculoskeletal and neuromuscular conditions that involve the temporomandibular joint (TMJ), the masticatory muscles (e.g., temporalis, masseter, and pterygoids), and the surrounding nerves and ligaments.

The prevalence of temporomandibular disorders is thought to be greater than 5% of the population, and Lipton and colleagues showed that about 6–12% of the population experience clinical symptoms of TMD.

2. Anatomy and the Body Systems Involved

The temporomandibular joint is a synovial hinge joint that connects the jaw to the skull, located just in front of each ear. Each joint is composed of the condyle of the mandible, an articulating disk, and the articular tubercle of the temporal bone.

The movements allowed are side to side, up and down, as well as protrusion and retrusion. This complicated joint, along with its attached muscles, allows the movements needed for speaking, chewing, and making facial expressions.

The TMJs are unusual because they are one of the only synovial joints in the human body comprising a disc meniscus. The disc separates the lower joint compartment (allowing rotational movement) from the upper joint compartment (allowing translational movements).

The disc, which is composed of dense fibrous connective tissue and shaped like a mature red blood cell, serves as a cushion between the bone surfaces. Unlike most joints, which are lined with hyaline cartilage, the TMJ bone surfaces are lined with fibrocartilage.

The body systems principally involved in TMD are:

• Musculoskeletal system: the masticatory muscles (temporalis, masseter, and pterygoids) and the ligaments of both joints.
• Nervous system: although the etiology remains obscure, various inflammatory mediators have been implicated; synovial fluid analysis indicates a role of cytokines and proteinases, and interleukins have been detected in both internal derangement and rheumatoid arthritis of the TMJ.
• Endocrine/hormonal system: the pain and dysfunction associated with TMDs are more prevalent among women during reproductive years, suggesting estrogen plays a role in TMD pathophysiology.
• Immune/inflammatory system: autoimmune and inflammatory disorders could potentially play a role in the development of TMD.

3. Clinical Presentation

Temporomandibular disorder refers to a group of conditions involving the orofacial region, divided into those affecting the masticatory muscles and those affecting the temporomandibular joint (TMJ). Typical features include TMJ pain, restricted mandibular movement, and TMJ sounds.

Temporomandibular disorders often present with pain in the jaw, face, and neck and/or with dysfunction of the jaw joint — often joint sounds and/or a decreased range of motion — that is frequently accompanied by other comorbidities including headache or ear pain.

Anterior disc displacement, with or without reduction, perforation of the retrodiscal tissue or the articular disc, and degenerative changes of the disc and/or the joint surfaces may be present. Clinically, it may be accompanied by pain, limitation of mouth opening, clicking, and locking.

Many TMDs last only a short time and go away on their own; however, in some cases they can become chronic, or long-lasting.

4. Contributing and Associated Factors

4.1 Multifactorial Etiology

The etiology of temporomandibular disorder (TMD) is multidimensional: biomechanical, neuromuscular, bio-psychosocial, and biological factors may contribute to the disorder.

The pathophysiology of TMJ syndrome is not entirely understood. The etiology is thought to be likely multifactorial, with contributing factors from multiple categories; both local insults and systemic disorders may be involved.

4.2 Biomechanical and Structural Factors

Local problems frequently arise from articular disc displacement and hereditary conditions affecting the structures of the joint itself, such as hypoplastic mandibular condyles. A study by Tallents et al. found TMJ displacement in 84% of patients with symptomatic TMJ versus 33% of asymptomatic subjects.

The TMJs can also be affected by conditions such as rheumatoid arthritis, juvenile idiopathic arthritis, osteoarthritis, and diseases of the articular disks.

A systematic literature review revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD, with variations in TMJ factors observed across different malocclusion classes. Additionally, the occurrence and attributes of TMD are influenced by the number of tooth-loss quadrants and the frequency of missing teeth.

4.3 Parafunctional Behaviors: Bruxism and Clenching

Oral behaviors can cause microtrauma or mechanical overload of the TMJ, which can result in joint disc displacement. Additionally, excessive joint activity deprives the orofacial muscles of necessary rest, resulting in pain. Bruxism, a common oral behavior, is believed to cause microtrauma to the TMJ and surrounding muscles, potentially leading to inflammation and pain.

Hypermobile TMJs, nocturnal jaw clenching, nocturnal bruxism, jaw clenching due to psychosocial stresses, and local trauma also play a significant role.

A systematic review found a correlation between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders.

4.4 Psychosocial Stress and Psychological Factors

Anxiety stands out as a comorbidity frequently associated with TMJ disorders, as it can change pain sensations and release neurotransmitters related to parafunctional habits. Anxiety can also potentiate the hyperactivity of chewing muscles associated with TMJ, resulting in joint overload.

Anxiety has an important role in TMD, and a person's general disposition to be anxious can be considered as a risk factor for TMD pain.

In addition to local pain, TMD has been implicated as being related to factors such as psychosocial stress, emotional disorder, and sleep disturbances. Sleep disturbances including insomnia, poor sleep quality, obstructive sleep apnea (OSA), and bruxism are commonly observed in the general population and are established contributors to chronic pain disorders.

4.5 Sex, Hormonal, and Reproductive Factors

Temporomandibular joint disorders affect women with greater frequency than men, and sex hormones may contribute to this female predominance.

Fluctuating levels of estrogen during childbearing age potentiates facial pain, high estrogen levels during pregnancy promote gingivitis, and low levels of estrogen during menopause predispose the TMJ to degeneration and increases alveolar bone loss.

A systematic review found that polymorphism in the alpha estrogen receptor appears to be significantly more prevalent in women with temporomandibular dysfunction, suggesting a genetic predisposition. There is a significant role of estrogen in the physiopathology of TMD-related pain. Women with polycystic ovary syndrome (PCOS) have a significantly higher incidence of TMD, accompanied by elevated inflammatory factors and decreased progesterone levels. In premenopausal women, there is scientific relevance to the association between beta-estradiol levels and TMD development and progression.

Recent studies in Europe and the US with larger patient sample sizes have shown that the prevalence for TMD peaks between 45 and 64 years of age and then gradually decreases. In the US study, TMD prevalence peaked at around 6% in 35–64 year-olds and then decreased to 4% in 65–84 year-olds.

4.6 Genetic Factors

It has been postulated that women and adolescents have a higher risk for TMDs compared to men. TMJ osteoarthritis (OA) is also diagnosed at the later stages of severe cases of TMDs.

Increasing scientific evidence suggests that genetic factors may play a significant role in the pathology of TMDs; however, the underlying mechanism of TMDs remains largely unknown.

4.7 Systemic and Inflammatory Conditions

The literature reports on the effect of raised blood pressure on the impairment of central pain regulatory systems and its potential contribution to painful TMD. Patients with temporomandibular disorder exhibit heightened sensitivity to aversive stimuli, implying that the presence of painful TMD may arise, to some extent, from dysfunction in central pain modulation mechanisms influenced by baseline arterial blood pressure.

Generalized joint hypermobility (GJH) is one of the pathophysiological contributing factors for the development of temporomandibular disorders (TMD).

5. Nutrients Studied in Relation to TMD

5.1 Omega-3 Fatty Acids

Mechanism of potential relevance: Preclinical studies have provided evidence supporting the effectiveness of omega-3 fatty acids in managing TMJ inflammation. Marana et al. demonstrated that systemic administration of omega-3 fatty acids led to a decrease in TMJ damage and reduced levels of proinflammatory cytokines, such as IL-1 beta and TNF-alpha, in rats subjected to ovariectomy and rheumatoid arthritis induction.

Preclinical evidence: Systemic administration of omega-3 fatty acids exhibited anti-inflammatory effects, as evidenced by decreased levels of various proinflammatory cytokines in facial inflammatory models. These findings highlight the potential of omega-3 fatty acids to inhibit local inflammation within the TMJ.

Evidence characterization: Evidence for omega-3 fatty acids and TMD specifically remains largely preclinical (animal models). No large-scale randomized controlled trials in human TMD populations have been identified in the peer-reviewed literature. The overall anti-inflammatory properties of omega-3 fatty acids are well-established in other joint conditions, but direct extrapolation to TMD requires caution.

5.2 Vitamin D

Observational research: A cross-sectional study with 110 subjects (55 TMD patients, 55 controls) found that the mean serum level of vitamin D was 18.13 ± 6.38 ng/mL in the TMD study group and 31.83 ± 7.00 ng/mL in the control group. Analysis demonstrated a significant difference between the two groups (p = 0.001), suggesting the serum level of vitamin D is lower in TMD patients than in healthy controls.

Parathyroid hormone levels were statistically significantly higher in patients with TMDs versus healthy control patients. In patients with temporomandibular disorders, increased parathyroid hormone levels in response to vitamin D deficiency were significantly more prominent. These data suggest that, in patients with temporomandibular disorders, vitamin D deficiency should be assessed and corrected. Vitamin D is a key element in calcium metabolism, and previous studies have shown that reduced serum levels of 25(OH)D are associated with musculoskeletal disorders such as chronic low back pain and fibromyalgia.

Interventional evidence: A double-blinded, parallel-group, randomized, placebo-controlled trial was conducted to comparatively evaluate vitamin D supplementation and stabilization splint therapy in patients exhibiting TMDs. Thirty-six participants aged 18–45 years with vitamin D deficiency and TMD were included. The study authors concluded that patients with TMD and vitamin D deficiency should be supplemented with vitamin D alongside splint therapy to provide faster relief in symptoms.

Conflicting and cautionary evidence: A bidirectional Mendelian randomization analysis revealed that within a European population, higher levels of vitamin D were associated with higher risks of developing temporomandibular disorders, but found no obvious evidence that TMDs are causally associated with vitamin D. Notably, existing research indicates a U-shaped correlation between vitamin D levels and their impact on the skeletal muscle system, implying the existence of an optimal level, beyond which both deficiency and excess can be detrimental.

Evidence characterization: Among the observational studies published to date investigating the role of vitamin D in the etiology of TMDs, six of them suggest a connection between the two aspects. However, the evidence is mixed, and the Mendelian randomization study introduces significant uncertainty. Results should be interpreted cautiously pending larger, well-designed trials.

5.3 Magnesium

Relevance to bruxism and muscle function: The present literature indicates potential negative effects of magnesium deficiency on the central nervous system; in animal studies, stress-induced muscle hyperactivity was associated with muscle dysfunction and pain.

In a study by Sarchielli et al., patients who suffered from migraine and tension-type headaches — very common symptoms in patients with bruxism and TMD — presented with significantly lower levels of serum and salivary magnesium. Hypomagnesaemia makes cerebral arteries more sensitive to CO₂, which promotes cerebral vasospasm and headache.

One prospective observational study found no statistically significant between-group differences in serum magnesium levels between TMD patients and healthy controls, though the same study did observe elevated parathyroid hormone, suggesting secondary effects on mineral metabolism. Evidence directly linking serum magnesium to TMD remains inconsistent and preliminary.

Evidence characterization: The connection between magnesium and bruxism/TMD is biologically plausible (via muscle relaxation and stress-pathway modulation) but current human clinical evidence is limited, with observational studies producing mixed results. Well-powered randomized trials specifically targeting magnesium in TMD populations are lacking.

5.4 Glucosamine and Chondroitin Sulfate

Background use in joint conditions: For years in veterinary medicine, glucosamine and chondroitin sulfates have been used to treat symptoms of osteoarthritis. Recently, the use of these two supplements has been recommended for human beings as well; reports of decreased joint noises, pain, and swelling after the administration of therapeutic doses of these supplements have sparked an interest in their possible use in the treatment of osteoarthritis.

Clinical trial in TMD: A randomized double-blind pilot study aimed to evaluate a daily dose of 1,500 mg of glucosamine hydrochloride and 1,200 mg of chondroitin sulfate taken for twelve weeks in subjects diagnosed with capsulitis, disk displacement, disk dislocation, or painful osteoarthritis of the TMJ. Forty-five subjects were enrolled; subjects taking the combination had improvements in pain as measured by one index of the McGill Pain Questionnaire, in TMJ tenderness, in TMJ sounds, and in the number of daily over-the-counter medications needed.

Synovial fluid cytokine study: A randomized clinical study aimed to evaluate the effects of a glucosamine-chondroitin sulfate combination on the internal derangements of the temporomandibular joint, comparing these effects with tramadol, a narcotic analgesic, in both clinical and biochemical terms.

Broader systematic review: Of 2,013 articles screened in a PRISMA systematic review, 146 studies were included, with nearly 60% being randomized controlled trials. Most studies focused on osteoarthritis and joint pain, with over 90% of efficacy studies reporting positive outcomes and most safety studies indicating minimal or no adverse effects. However, the majority of this evidence base concerns the knee, not the TMJ specifically.

Evidence characterization: For TMD specifically, the evidence from human randomized trials is preliminary and from small samples. Pilot data are suggestive of benefit in TMJ osteoarthritis and internal derangement; larger controlled trials are needed before definitive conclusions can be drawn.

6. Herbs and Plant-Derived Compounds Studied or Traditionally Used

6.1 Curcumin (Turmeric, Curcuma longa)

Traditional use: Turmeric (Curcuma longa) has a long history of use in Ayurvedic and traditional Chinese medicine as an anti-inflammatory and analgesic agent, typically prepared as a rhizome powder in foods, decoctions, or pastes applied topically for joint and musculoskeletal pain.

Preclinical evidence in TMD: Systemic administration of curcumin inhibited pain-like behaviors in the hindpaw, trigeminal neuralgia model, and orofacial formalin pain model. An in vitro study revealed that curcumin can inhibit key molecular processes in TMJ inflammatory chondrocytes, suggesting antinociceptive roles.

Research has also examined the effects of cranberry components on IL-1β-stimulated production of IL-6, IL-8, and VEGF by human TMJ synovial fibroblasts, published in the Archives of Oral Biology.

Clinical evidence for osteoarthritis (general, not TMD-specific): Meta-analyses of eight randomized controlled trials with more than 800 participants with primarily knee osteoarthritis found scientific evidence that supports the efficacy of turmeric extract (about 1,000 mg/day of curcumin) in treating OA. Curcumin may have some beneficial effects on knee pain and quality of life in patients with knee OA. Although curcumin is less effective at relieving pain than ibuprofen, it appears safe for short-term use and may reduce the need for rescue medication.

Evidence characterization: While twelve preclinical studies suggest promising therapeutic roles for curcumin and polyphenols in managing painful TMDs, further longitudinal and randomized controlled trials are needed to confirm their potential benefits, and the clinical efficacy of polyphenols in TMD is unclear.

6.2 Boswellia (Boswellia serrata)

Traditional use: Boswellic acid, derived from the resin of Boswellia serrata (Indian frankincense), has been used in Ayurvedic medicine for centuries for inflammatory joint conditions, including as a topical application and oral resin preparation.

Clinical evidence for osteoarthritis (general): A clinical trial assessed the efficacy and safety of curcuminoid complex from turmeric rhizome and its combination with boswellic acid extract from Indian frankincense root versus placebo in patients with osteoarthritis (OA), using 500-mg capsules taken orally three times per day for 12 weeks in 201 patients. No TMD-specific clinical trials for boswellia were identified in this literature search.

Evidence characterization: Evidence for boswellia in TMD specifically is absent. Available evidence relates to general osteoarthritis of other joints. Extrapolation to TMD should be made with caution.

6.3 Capsaicin

Traditional use: Capsaicin from chili peppers (Capsicum spp.) has been used topically in traditional medicine across Latin American, Asian, and Indigenous North American traditions for local pain relief.

Clinical evidence in TMD: In a study by Campbell et al. (2016), 15 patients with TMD were treated with a high-concentration capsaicin (8%) cream or placebo for a week, and the results showed a significantly higher pain-relief response in the week after application in the capsaicin-treated subjects with TMD.

Evidence characterization: This is a small, single study. While the result is promising, the very small sample size severely limits its generalizability. Further clinical study is warranted.

6.4 Herbal Topical Preparations (Menthol/Camphor-Based)

Traditional use: Herbal compresses and topical ointments containing menthol, camphor, and aromatic plant oils have been used across Southeast Asian and Chinese traditional medicine systems for musculoskeletal pain relief.

Clinical evidence: In a study, 55 subjects with temporomandibular joint pain received Ping On ointment containing Mentha piperita, Cinnamomum camphora, Gaultheria fragrantissima, Santalum album, and eucalyptus, or a placebo, for 4 weeks. Patients reported that Ping On ointment significantly reduced the painful symptoms of the TMJs, and they felt more comfortable opening their mouths than the placebo group.

A study by Chaimano et al. (2021) showed that subjects with myogenic TMD pain who underwent pain treatment with a herbal compress ball — containing Cassumunar ginger, turmeric, and camphor — had greater pain-free maximum opening compared to those who only used the warm placebo.

Evidence characterization: These studies provide initial proof-of-concept for topical herbal preparations in TMD pain but are limited by small sample sizes and methodological variability. They cannot establish efficacy for any single constituent.

6.5 Resveratrol

Traditional use: Resveratrol is a stilbenoid polyphenol found naturally in grape skins, mulberries, and some nuts; its concentrated use as a dietary supplement or botanical extract is a modern phenomenon without classical ethnomedicinal tradition as an isolated compound.

Preclinical evidence in TMD: Resveratrol (RSV) is a natural bioactive compound found in various plants, especially grape skins and red wines. Due to its antioxidant and anti-inflammatory properties, RSV has been proved to improve pathological and behavioral outcomes in the treatment of different neurological disorders, including trigeminal neuropathic pain in rats and chronic neuropathic pain in mice.

Studies suggest that RSV may be used to treat TMJ inflammatory pain by restoring normal gut microbiota and thereafter regulating microglial activation and the release of pro-inflammatory cytokines such as TNF-alpha. Systemic administration of RSV dose-dependently inhibited CFA-induced TMJ inflammation and reversed CFA-caused reduction of short-chain fatty acids and gut bacteria.

Fecal microbiota transplantation with feces from RSV-treated mice significantly diminished CFA-induced TMJ inflammation, suggesting that gut microbiome perturbation is critical for the development of TMJ inflammation and that recovering gut microbiome to normal levels could be a new therapeutic approach for treating such pain. This research is entirely preclinical (rodent models).

Evidence characterization: Resveratrol's role in TMJ inflammation is supported by animal experimental data only. No human clinical trials in TMD populations were identified. The gut-microbiome-TMJ axis represents an emerging and scientifically interesting but unproven therapeutic target.

6.6 Quercetin and Epigallocatechin Gallate (EGCG)

Preclinical evidence: Local administration of quercetin, a flavonoid phytochemical, exerted inhibitory effects on nociceptive neural activities evoked by facial stimulation in trigeminal primary sensory neurons in the presence and absence of persistent facial inflammatory conditions. Further, (−)-epigallocatechin-3-gallate, the main catechin contained in green tea, could inhibit nociceptive neural activities in the trigeminal subnucleus caudalis region.

Traditional use: Green tea (Camellia sinensis), the primary source of EGCG, has been consumed for centuries in East Asian traditions and is traditionally valued for its antioxidant and anti-inflammatory properties. Quercetin is widely distributed in fruits and vegetables and is found in traditional herbal preparations, though it was not historically isolated as a single compound.

Evidence characterization: Evidence is limited to animal and in vitro models. No human clinical trials testing quercetin or EGCG specifically for TMD have been identified.

7. The Gut Microbiome — an Emerging Research Direction

Growing evidence has reported that microglia morphology and function depend on the alteration of gut microbiota, including short-chain fatty acid production (acetic acid, propionic acid, and butyric acid), affecting the immune system and subsequently modulating the inflammatory status.

The gut-brain-TMJ axis, though biologically plausible based on preclinical data with resveratrol and microbiome transplantation experiments, has not yet been validated in human TMD studies. This represents a frontier area of research rather than an established nutritional strategy.

8. Dietary Factors Discussed in the Literature

8.1 Mechanical Dietary Load: The Soft Diet Principle

A possible influence of food bolus properties, such as stiffness and size of the food piece, on TMJ biomechanics is of special interest, since clinicians often recommend a diet consisting of small and soft pieces of foods as part of TMD self-management guidelines. While these recommendations sound reasonable, only a rather limited amount of scientific evidence exists; a proper understanding of the effect of food bolus properties on muscle activation patterns and in turn TMJ loading could help inform and update TMJ self-management guidelines.

Advice about a "soft diet" may be useful in the short-term alleviation of temporomandibular disorders, but may contradict the long-term aims of multi-dimensional approaches if not carefully managed. The widespread clinical recommendation for a soft diet during acute TMD flares thus lacks a strong evidence base but is consistent with the biomechanical logic of reducing mechanical joint loading.

8.2 Anti-Inflammatory Dietary Patterns

While no randomized controlled trials specifically examine an "anti-inflammatory diet" as a whole-dietary-pattern intervention for TMD, the inflammatory pathophysiology of TMD — involving elevated cytokines such as IL-1β, IL-6, and TNF-α in synovial fluid — provides a biologically plausible framework for recommending dietary patterns known to reduce systemic inflammation, such as Mediterranean-style diets high in omega-3 fatty acids, polyphenols, and fiber.

8.3 Nutrient Deficiencies and Pain Sensitivity

The research literature discusses the potential negative effects of certain vitamin and mineral deficiencies — including vitamin D, magnesium, and omega-3 fatty acids — on the central nervous system and, by extension, on pain processing.

In one observational study with 100 subjects, compared with control groups, subjects with sleep bruxism had higher anxiety and depression rates, and their vitamin D levels were significantly lower.

8.4 Sugar, Processed Foods, and Inflammatory Foods

High intake of pro-inflammatory foods (refined sugars, processed foods, trans fats) is broadly implicated in promoting systemic inflammation through well-established mechanisms, including activation of NF-κB and elevation of inflammatory cytokines. Because elevated cytokines are directly detected in TMJ synovial fluid, an overall pro-inflammatory dietary pattern is conceptually relevant, though direct clinical evidence linking specific dietary patterns to TMD outcomes remains sparse in the peer-reviewed literature.

9. Lifestyle Factors Discussed in Authoritative Sources

9.1 Sleep and Sleep Disorders

Sleep disturbances including insomnia, poor sleep quality, obstructive sleep apnea (OSA), and bruxism are commonly observed in the general population and are established contributors to chronic pain disorders. TMD patients, in comparison with healthy controls, have poorer quality of sleep.

9.2 Psychosocial Stress Management

Parafunctional habits such as clenching, grinding, and abnormal jaw positioning have been proposed as contributing factors to TMD; yet their individual and cumulative contributions remain unclear. Exploratory research has evaluated the prevalence and severity of parafunctional habits and their association with TMD in medical students — a group exposed to elevated stress levels.

Psychological factors may contribute to chronic upregulation of the HPA axis, with higher salivary cortisol secretion from the adrenal cortex.

9.3 Physical Activity and Posture

Poor oral habits, posture, and even breathing patterns can contribute significantly to TMJ disorders. Beyond dietary adjustments, understanding the mechanics of the jaw and mouth is crucial.

9.4 Hydration

Adequate hydration is consistently noted as supportive of synovial joint function. While direct clinical evidence linking hydration to TMD outcomes is absent in the peer-reviewed literature reviewed here, maintenance of joint lubrication and tissue integrity is a reasonable physiological rationale for ensuring adequate fluid intake.

10. Summary of Evidence Strength by Intervention

• Glucosamine + Chondroitin Sulfate: Small randomized pilot trials directly in TMD populations show preliminary benefit in pain, joint sounds, and tenderness. Evidence is promising but insufficient for firm recommendations. Larger RCTs are needed.
• Vitamin D: Multiple observational studies show lower levels in TMD patients; one small RCT supports supplementation as adjunct to splint therapy in deficient patients. A Mendelian randomization study introduces conflicting data. Overall: preliminary and mixed.
• Omega-3 Fatty Acids: Preclinical (animal) evidence for TMJ-specific anti-inflammatory effects. Indirect human evidence from other joint conditions. No TMD-specific RCTs identified. Evidence is preliminary.
• Magnesium: Biologically plausible via muscle relaxation and stress pathways; indirect observational links via bruxism and headache research. No TMD-specific clinical trials identified. Evidence is indirect and preliminary.
• Curcumin: In vitro and animal evidence for TMJ chondrocyte protection. Human RCTs exist for general OA (knee) but not TMD. Evidence is preclinical/indirect.
• Capsaicin (topical): Single very small RCT (n=15) in TMD showing pain relief. Evidence is very preliminary.
• Topical herbal compresses: Small clinical studies in myogenic TMD showing benefit; evidence is limited but human.
• Resveratrol: Animal-model data only for TMJ. No human trials. Evidence is preclinical only.
• Quercetin, EGCG: Animal and in vitro data only for craniofacial pain. No human TMD trials. Evidence is preclinical only.
• Soft diet: Widely clinically recommended; mechanistically sound but limited formal clinical trial evidence.

References

• National Institute of Dental and Craniofacial Research (NIDCR): TMD (Temporomandibular Disorders)
• StatPearls — Temporomandibular Syndrome (NCBI Bookshelf)
• Merck Manual Professional: Overview of Temporomandibular Disorders (TMDs)
• Medscape: Temporomandibular Joint (TMJ) Syndrome — Pathophysiology and Epidemiology
• Etiologic Factors of Temporomandibular Disorders: A Systematic Review (Healthcare, MDPI, 2024)
• Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review (PMC)
• Frontiers in Psychiatry: Association between Temporomandibular Disorders and Anxiety: A Systematic Review (2022)
• Gene Mutations Associated with Temporomandibular Joint Disorders: A Systematic Review (PMC)
• Estrogen Receptor-α Polymorphisms and Predisposition to TMJ Disorder (PMC)
• Estrogen Hormones' Implications on the Physiopathology of Temporomandibular Dysfunction (PMC, 2024)
• Estrogen Signaling Impacts Temporomandibular Joint and Periodontal Disease Pathology (PMC)
• Craniomandibular Disorders in Pregnant Women: An Epidemiological Survey (PMC)
• Nutritional Strategies for Chronic Craniofacial Pain and Temporomandibular Disorders: Current Clinical and Preclinical Insights (MDPI Nutrients / PMC, 2024)
• Polyphenols as Potential Agents in the Management of Temporomandibular Disorders (MDPI Applied Sciences, 2020)
• Herbal Extracts in Orofacial Pain: A Systematic Review and Direct and Indirect Meta-Analysis (PMC)
• Evaluation of Local Application of Glucosamine Sulfate and Chondroitin Sulfate on TMJ Response: A Randomized Control Clinical Trial (PMC)
• A Randomized Double-Blind Clinical Trial of the Effect of Chondroitin Sulfate and Glucosamine Hydrochloride on TMJ Disorders: A Pilot Study (PubMed)
• Glucosamine, Chondroitin Sulfate, and Methylsulfonylmethane Supplementation and TMJ Osteoarthritis Management: A Randomized Clinical Trial (PubMed)
• The Safety and Efficacy of Glucosamine and/or Chondroitin in Humans: A Systematic Review (PMC)
• Vitamin D and Temporomandibular Disorders: What Do We Know So Far? (PMC)
• Is the Prevalence of Vitamin D Deficiency in Patients with Temporomandibular Disorder Higher than Healthy Control Group? (PMC)
• Biochemical Changes Associated with Temporomandibular Disorders (PMC)
• Effectiveness of Vitamin D along with Splint Therapy in Vitamin D Deficient Patients with TMD: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial (PMC)
• Vitamin D Levels and Temporomandibular Disorders: A Bidirectional Two-Sample Mendelian Randomization Analysis (PMC)
• Nutrient Insufficiencies and Deficiencies Involved in the Pathogenesis of Bruxism (Review) (PMC)
• Efficacy and Safety of Curcumin and Its Combination with Boswellic Acid in Osteoarthritis: A Comparative, Randomized, Double-Blind, Placebo-Controlled Study (PMC)
• Nrf2/ARE is a Key Pathway for Curcumin-Mediated Protection of TMJ Chondrocytes from Oxidative Stress and Inflammation (PMC)
• Resveratrol Alleviates Temporomandibular Joint Inflammatory Pain by Recovering Disturbed Gut Microbiota (PMC)
• Association of Sleep Disorders with Temporomandibular Joint Pain Dysfunction Syndrome (PMC)
• Temporomandibular Disorders and Dietary Changes: A Cross-Sectional Survey (Journal of Oral Rehabilitation, Wiley, 2021)
• The Effect of Bolus Properties on Muscle Activation Patterns and TMJ Loading During Unilateral Chewing (bioRxiv)
• Association between Generalized Joint Hypermobility, Temporomandibular Joint Hypertranslation and Temporomandibular Disorders: A Scoping Review (PMC, 2025)
• Risk Factor Assessments of Temporomandibular Disorders via Machine Learning (Scientific Reports, 2021)