What is the cause of TMD?

• A. Genetic predisposition only
• B. Multifactorial
• C. Bacterial infection
• D. Poor oral hygiene

Answer: (B)

TMD is best understood as multifactorial in origin, meaning multiple interacting factors contribute to its development and expression. The jaw joint and the muscles that move it can be affected by mechanical stress, parafunctional activities like clenching or grinding, inflammation, and changes in joint structure such as disk displacement. Genetic predisposition can influence tissue resilience and pain sensitivity, but it typically interacts with environmental triggers—trauma to the jaw, bite misalignment, arthritis, stress, and sleep disturbances—so many patients have several contributing factors at once. Because of this combination of influences, there isn’t a single cause that fits all cases; the disorder arises from the interplay of biological, psychological, and mechanical factors, which is why a multifactorial explanation best accounts for the variety of symptoms and presentations.

Bacterial infection does not drive TMD, and while poor oral hygiene affects dental health, it does not directly cause TMJ or muscle dysfunction. Genetic predisposition can play a role, but it doesn’t alone explain cases where non-genetic factors initiate symptoms.