Mouthguards are standard protective appliances used primarily to shield teeth from impact injuries during contact sports or to prevent damage caused by nocturnal teeth grinding (bruxism). While designed to safeguard oral health, many users worry: can a mouthguard inadvertently cause dental misalignment or shift the position of their teeth? The answer depends almost entirely on the type of guard used, its fit, and the duration of its wear. A properly fitted appliance should maintain current dental alignment, but certain conditions can cause the device to exert unintended orthodontic force.
Types of Mouthguards and Associated Risks
The potential for a mouthguard to shift teeth is directly related to how well it conforms to the unique shape of the wearer’s mouth. The lowest-cost option is the stock mouthguard, which is pre-formed and ready to wear immediately, offering a one-size-fits-all shape that provides the highest risk of a poor fit. These often feel bulky and may not stay securely in place, which means they can apply uneven pressure to specific teeth.
A marginally better alternative is the boil-and-bite mouthguard, which is made from a thermoplastic material softened in hot water and then molded by biting down. While this allows for some customization, the lack of professional supervision often results in an inaccurate mold that can still be too bulky or apply inconsistent pressure points. The most secure option is the custom-fitted mouthguard, created by a dentist from an exact impression of the patient’s teeth. These guards are designed to distribute pressure uniformly and offer the lowest risk of causing unintended tooth movement due to their precise fit.
How and Why Mouthguards Can Shift Teeth
The basic principle behind any intentional tooth movement, such as with braces or clear aligners, is the sustained application of light, constant pressure on the teeth and their supporting bone. A mouthguard can become an unintentional orthodontic device when it applies this same type of sustained, uneven force. This is the primary reason that ill-fitting, generic, or over-the-counter guards pose a greater risk than custom-made ones.
An improperly molded boil-and-bite or stock guard may exert pressure unevenly on one side of a tooth or a particular group of teeth. If this pressure is applied consistently over many hours each night or day, it can slowly cause the teeth to drift out of their current alignment. The duration of wear also significantly influences the risk, as an ill-fitting guard worn for excessive periods provides the necessary time for the bone remodeling process that leads to shifting.
Certain designs can also introduce risk, particularly those that only cover the front teeth. These partial-coverage appliances can alter the natural way the upper and lower teeth meet, destabilizing the bite and leading to changes in tooth position. Furthermore, some dental appliances, such as those used to treat sleep apnea, are specifically designed to hold the jaw in a forward position; this intentional realignment must be monitored closely by a dental professional. While a well-fitting guard stabilizes the teeth and distributes forces evenly, if the guard becomes warped or worn down, it loses this function and can press on teeth incorrectly.
Ensuring a Safe and Non-Harmful Fit
To mitigate the risk of unwanted tooth movement, the choice of mouthguard should prioritize an accurate fit over convenience or cost. Consulting with a dentist before beginning long-term use of any oral appliance, especially a night guard for bruxism, helps ensure the device is appropriate for your specific needs. Custom-fitted mouthguards are fabricated to the exact contours of your dental arch and are the most effective way to prevent pressure inconsistencies.
Users should monitor their mouthguard for signs of a poor fit, including subtle changes in how teeth align upon waking, persistent soreness, or localized pressure spots. Difficulty speaking, a feeling of bulkiness, or the guard consistently shifting out of place are also indicators that the appliance is not fitting correctly. Regular dental check-ups are necessary to monitor the stability of the bite and alignment, allowing for adjustments before minor pressure spots cause lasting tooth movement. Proper care, such as avoiding exposure to heat, helps prevent the material from warping and compromising the precise fit.