An occlusal splint, commonly known as a night guard, is a custom-fitted appliance worn over the teeth to prevent teeth grinding and clenching (bruxism). This protective barrier cushions the chewing surfaces and relieves strain on the temporomandibular joint, or jaw joint. A precise fit is necessary for the night guard to function correctly. A poorly fitting guard can potentially worsen jaw pain or even cause unintended tooth movement.
Distinguishing Normal Adjustment from Poor Fit
When a new night guard is introduced, the mouth and jaw muscles must adapt. This initial break-in period typically lasts between three to seven days, though some individuals may require a few weeks to fully acclimate. During this time, it is normal to experience minor pressure or a feeling of snugness on the teeth. Minor muscle fatigue and a temporary increase in salivation may also occur.
These temporary symptoms are distinct from those that indicate a structural fitting problem requiring correction. A poor fit is characterized by sharp, persistent pain or an inability to close the mouth comfortably. If the guard causes persistent, extreme soreness, or if the pressure feels significantly uneven on one side of the dental arch, the fit is incorrect. A guard that is too loose, constantly shifts, or causes persistent irritation to the gums and cheeks signals a necessary intervention.
Limited Home Adjustment Techniques
Custom-made night guards, fabricated from precise impressions, should never be subjected to user modification. Trimming, filing, or attempting to reshape a custom guard can destroy the delicate, therapeutic bite alignment engineered by the dental laboratory, rendering the appliance useless or even harmful.
For over-the-counter (OTC) or “boil-and-bite” guards, minor adjustments can be performed with caution. If the edges feel sharp or rough against the soft tissues of the mouth, minor trimming can be done using clean, small scissors or a nail clipper. Remove only small amounts of material to alleviate irritation without compromising the guard’s integrity. If the initial impression for a boil-and-bite guard was poor, a second, brief re-molding attempt may be possible using warm, not boiling, water according to the product’s instructions.
Indicators That Require a Professional Adjustment
A professional dental adjustment becomes mandatory when the fit issue is structural, involves the bite, or produces severe, lasting symptoms. The development or persistence of temporomandibular joint (TMJ) symptoms, such as clicking, popping, or chronic pain, suggests the guard is not providing correct joint support. Another sign is a change in the natural bite alignment, where the teeth do not meet correctly when the night guard is not being worn.
When a patient seeks professional intervention, the dentist utilizes specific tools to analyze the fit and function of the guard. The professional will often use articulating paper, a thin, dyed film, to identify “high spots” where the opposing teeth contact the guard with excessive force. These high spots appear as intensely colored marks on the guard’s surface, indicating uneven pressure distribution. The dentist then uses specialized rotary instruments, such as dental burrs, to selectively remove minute amounts of the acrylic material from the high spots.
This process is highly controlled to ensure the occlusal surface is evenly balanced, confirming that the opposing arch contacts the guard simultaneously and with uniform pressure. In some cases, a dentist may add small amounts of composite or acrylic material to the guard to improve retention or correct a significant void in the fit. Complex occlusal adjustments, which involve modifying the way the upper and lower jaws meet, require a professional’s expertise to protect the underlying dental structure and should never be attempted at home.