Whether teeth should be touching when the jaw is completely relaxed is a common question, and the answer is no. When the jaw muscles are at rest, the upper and lower teeth should not be in contact. Constant, unconscious contact is a form of clenching, known medically as bruxism. Chronic clenching strains the muscles and joints that control jaw movement, creating tension that can lead to pain and damage over time. This issue is often tied to muscle strain, stress, and poor resting posture.
The Ideal Resting Position
The proper, relaxed position of the jaw requires the muscles to be completely at ease and the teeth slightly separated. This small space between the upper and lower teeth is called the “freeway space.” This gap represents the minimal distance required for the jaw muscles to be in a state of minimal contraction.
The correct resting posture for the tongue is also important. The entire tongue should be gently suctioned against the roof of the mouth (the hard palate). The tip of the tongue should rest just behind the front teeth, without touching them.
When the jaw is relaxed, the lips should be gently closed, but the teeth must remain apart. This resting position ensures the temporomandibular joints (TMJs) are not under constant load and that the surrounding muscles are not fatigued.
Causes of Unconscious Clenching
The primary triggers for unconscious clenching during waking hours, known as awake bruxism, are psychological factors like stress, anxiety, frustration, or anger. Many people unconsciously clench their teeth as a coping mechanism or when concentrating intensely on a task. This reflexive tension response forces the jaw muscles to tighten.
Clenching that occurs during sleep, known as sleep bruxism, is often associated with other sleep issues, such as snoring and obstructive sleep apnea. It involves brief disturbances in sleep cycles and may be linked to certain medical conditions or medications, including some antidepressants.
Structural factors can also encourage improper resting posture. An improper bite, or malocclusion, can sometimes cause the jaw to seek a more comfortable, though incorrect, resting position. Lifestyle factors like heavy consumption of caffeine or alcohol, as well as smoking, are also risk factors that increase muscle tension and contribute to bruxism.
Consequences of Chronic Contact
The constant force from chronic clenching leads to significant wear and damage to dental structures. The enamel can be worn down or chipped by the repetitive pressure. This loss of protective enamel exposes the underlying dentin, resulting in increased tooth sensitivity to temperature changes or pressure.
This chronic muscular overactivity often manifests as pain in the face, head, and neck. Many individuals experience tension-type headaches that start near the temples due to strained jaw muscles. Earaches are another common symptom, as the jaw joint is located very close to the ear canal.
Persistent clenching is a major contributor to Temporomandibular Joint Disorder (TMD). Symptoms of TMD include tired or tight jaw muscles, a limited range of jaw opening, and painful clicking or popping sounds when the jaw moves. In severe cases, chronic muscle use can cause the jaw muscles to become noticeably enlarged.
Strategies for Jaw Relaxation and Relief
The first step in managing clenching is behavioral modification, focusing on increasing awareness of the habit during the day. A simple technique is using a mantra like “lips-together, teeth-apart” to remind yourself to maintain the freeway space. Consciously relaxing the jaw whenever tension is noticed helps retrain the muscles to adopt the proper resting position.
Simple exercises can also help relieve muscle strain and promote relaxation. One technique involves placing the tip of the tongue on the roof of the mouth and slowly opening the mouth while keeping the tongue in place. Applying warm compresses to the sides of the face can soothe tight jaw muscles, and gentle massage helps diminish muscle knots.
For sleep bruxism, a custom-fitted nightguard is often recommended. This device provides a cushion between the upper and lower teeth, protecting them from physical damage and reducing the load on the TMJs. For severe muscle tension, professional treatments may include physical therapy or botulinum toxin injections, which temporarily relax the overworked jaw muscles.