A night guard is an oral appliance, typically made from acrylic or plastic, designed to protect your teeth from the damaging forces of grinding or clenching (bruxism). For the device to work, it must maintain a secure, snug fit over your teeth throughout the night. If you frequently wake up to find your night guard dislodged, it indicates a failure in the retention mechanism. Understanding the cause of this displacement is the first step toward ensuring your teeth remain protected.
Primary Causes of Displacement
The most common reason for a night guard to fall out is a failure of the initial fit, which relies on the appliance being molded precisely to the unique contours of your teeth. Over-the-counter or “boil-and-bite” guards are often too generic, lacking the deep undercuts necessary to grip the teeth securely. Without this precise fit, the forces generated during sleep can easily push the guard out of position. Retention of a custom guard comes from the accurate fit around the cervical undercut area, the slight narrowing where the tooth meets the gumline.
Even a professionally made guard is not permanent, as wear and tear or changes in your mouth can compromise its fit over time. Constant grinding forces can cause the material to degrade, thin out, or soften, reducing its snugness. Recent dental work, such as new fillings, crowns, or extractions, can subtly alter the landscape of your mouth, rendering a previously well-fitting guard obsolete. A guard that is too loose will inevitably shift and detach.
How Sleep Habits Contribute to the Problem
Physiological factors while you sleep can disrupt even a perfectly fitted night guard. Mouth breathing is a significant factor, as it causes the oral cavity to dry out. The suction that keeps a night guard secured is dependent on hydrostatic adhesion, a force created by a thin layer of saliva between the guard and your teeth. When the mouth dries, this adhesion is significantly reduced, making it easier for the guard to be dislodged.
The intensity of your bruxism plays a direct role in displacement. Bruxism can generate forces 10 to 15 times greater than normal chewing pressure. If clenching or grinding is severe, the sheer muscular activity can physically pop a guard off the teeth. Certain medications or health conditions can affect saliva production or thickness, impacting the hydrostatic seal necessary for retention.
Steps to Achieve a Secure Fit
The most effective step is seeking a professional assessment and adjustment from your dentist. They can inspect the guard for internal pressure points or rough edges and use specialized tools to trim or smooth the acrylic. A dentist can apply a relining material to the inner surface of the guard to enhance its grip and restore the snug, custom fit.
Proper daily care is essential to maintaining the guard’s structural integrity and fit. Always clean the appliance with cool water and a soft brush immediately after use to remove saliva and plaque, which can alter the fit. Avoid hot water and extreme temperatures, such as leaving the guard in a sunny car, as the thermoplastic material can warp, causing a permanent loss of fit.
If mouth breathing is the contributing factor, discussing this with a doctor is advisable, as it may be linked to underlying issues like allergies or sleep apnea. Addressing these root causes can improve nasal breathing and saliva flow, which restores the natural retention mechanism of the guard.
A custom-fitted night guard should last between two to five years. If it begins to feel persistently loose or shows significant cracking, it needs to be replaced to ensure continued protection.