A night guard, often called an occlusal splint, is a removable dental appliance designed to fit over the upper or lower teeth. Its primary function is to prevent damage caused by unconscious grinding or clenching, known as bruxism. The device also helps manage Temporomandibular Joint (TMJ) disorder symptoms by reducing strain on the jaw muscles. While the goal is stabilization, users often worry if the guard can inadvertently cause teeth to shift. A properly fitted, full-coverage guard should not move teeth, but certain types or improper use can lead to unwanted dental changes.
The Purpose of Night Guards
The purpose of a night guard is protective and non-orthodontic. By interposing a layer of hard acrylic or plastic between the teeth, the guard absorbs the intense forces generated during bruxism. This cushioning prevents the direct wear and tear that leads to chipped, cracked, or flattened tooth surfaces.
The stabilization splint, the most common type, distributes biting pressure evenly across the dental arch. This distribution helps the jaw muscles relax and encourages the jaw joint to rest in a less strained position. The device stabilizes the existing alignment, minimizing the excessive movement that might otherwise cause teeth to shift out of place.
How Unintended Tooth Movement Occurs
Teeth shift when subjected to sustained, uneven pressure. If a night guard is ill-fitting or poorly designed, it can unintentionally replicate this force, leading to changes in the bite. This movement occurs primarily through partial coverage and inaccurate fit.
A common cause is using a partial-coverage guard, which only covers a segment of the teeth, such as the front six. Since the back teeth are left without contact, they may attempt to erupt over time to meet the opposing arch. This phenomenon can result in an open bite where the back teeth no longer touch, or the continuous pressure on the covered teeth can push them out of position.
Unwanted movement also stems from inaccurate occlusal registration, such as high spots or uneven thickness in the guard itself. If the splint is molded incorrectly or warps, it may place constant, excessive force on just one or two teeth. This sustained, localized pressure acts like a permanent retainer, slowly driving those specific teeth into a new position.
Custom Fit Versus Over-the-Counter Devices
The risk of tooth shifting is closely tied to the type of night guard used. Custom-fitted devices offer the highest safety profile, as they are fabricated by a dental lab using an exact mold of the patient’s teeth. This ensures a snug fit and uses hard, durable acrylic material that maintains its shape and provides full, balanced coverage across the arch.
In contrast, over-the-counter (OTC) options, like boil-and-bite or generic guards, pose a much greater risk of causing unwanted movement. These devices are often made from softer plastics that can warp easily or encourage users to chew on them, changing the material’s thickness and fit. Because they lack the precise fit of a custom appliance, OTC guards frequently distribute force unevenly or fail to provide comprehensive coverage, leading to bite changes.
Preventing Unwanted Tooth Shifts
The most effective way to prevent a night guard from shifting teeth is to begin with a professional dental assessment. A dentist determines the correct type of splint, which is usually a hard, full-coverage appliance appropriate for the individual’s grinding pattern. The guard must cover all teeth in the arch, ensuring no individual teeth are left uncovered.
Once the guard is delivered, regular check-ups are necessary to verify the fit and adjust any high points on the surface. These professional adjustments eliminate areas that could be applying unintended orthodontic pressure. If the user notices persistent discomfort, significant changes in how the teeth come together, or looseness in the appliance, they should stop wearing the guard immediately and consult their dental provider.