What are common parafunctional habits contributing to TMD?

• A. Clenching, grinding, bruxism
• B. Chewing gum frequently
• C. Biting nails
• D. Humming loudly

Answer: (A)

Parafunctional jaw activities that place excessive, repetitive load on the TMJ and masticatory muscles are the most common contributors to TMD. Clenching and bruxism fit this pattern perfectly because they involve sustained or repeated teeth-to-teeth contact and strong muscle contraction, often without regard to function. This overuse stresses the jaw muscles and the joint itself, leading to muscle fatigue, myofascial pain, headaches, and sometimes joint noises or limited movement. Sleep bruxism or awake clenching are frequently seen in people with TMD, making this combination the most likely cause.

Chewing gum regularly involves jaw movement and can fatigue muscles if done excessively, but it is usually considered a functional activity related to chewing rather than a parafunctional habit that overloads the TMJ. Biting nails is a parafunctional habit, but it is less consistently linked to TMD symptoms than clenching and grinding. Humming, on the other hand, does not produce the same jaw-loading pattern and is not a typical source of TMD symptoms.