Teeth clenching is often related to stress or anxiety. While it does not always cause symptoms, some people experience facial pain, headaches, and worn down teeth over time. Most people who clench their teeth are not even aware that they are doing it. Stress is one of the most common causes of teeth clenching. Teeth clenching can occur during the day or throughout the night, which can cause facial muscles to tighten up over time, or lead to more serious dental problems such as tooth damage and even tooth loss. Other signs of stress include: - Clenching of the fist - Tension in the shoulder and neck muscles