A retainer should not be used as a mouthguard, a practice highly discouraged by dental professionals. These two oral appliances are fundamentally different, serving opposing purposes. A retainer is engineered to hold teeth in their corrected position after orthodontic treatment. Conversely, a mouthguard is designed as a shock absorber, intended to dissipate the force of impact or grinding pressure to protect the teeth, gums, and jaw structure. Substituting a retainer for a protective guard compromises both the retainer’s function and the user’s oral safety.
Design Differences Between Retainers and Mouthguards
The structural composition of a retainer is optimized for passive retention, which necessitates a very thin, rigid material. Most clear retainers are fabricated from a thin plastic material, often Essix plastic, measuring approximately 1 millimeter in thickness. This minimal thickness allows the retainer to fit snugly against the teeth without interfering significantly with bite alignment. The material is hard enough to maintain tooth position but not resilient enough to absorb concussive forces.
In contrast, a mouthguard is constructed from thick, resilient thermoplastic polymers, such as Ethylene Vinyl Acetate (EVA). These protective devices are substantially thicker, typically ranging from 3 to 6 millimeters, which is necessary to create a cushioning layer. This bulk and flexibility allow the mouthguard to absorb and distribute the kinetic energy of an impact across the entire arch of the jaw. While a retainer only covers the surfaces needed for retention, a mouthguard is designed to cover the teeth, gums, and surrounding bone structure for comprehensive trauma protection.
Potential Damage When Using a Retainer as Protection
Using a thin, rigid retainer for activities requiring impact protection, such as contact sports, increases the risk of appliance failure and serious oral injury. Under impact, the retainer’s thin acrylic material will not absorb the force but will fracture or splinter. This breakage destroys the orthodontic appliance, requiring replacement, and creates jagged, sharp edges inside the mouth.
A fractured retainer can cause lacerations to the soft tissues of the mouth, including the cheeks, lips, and tongue. The lack of shock absorption means the full force of the impact is transferred directly to the teeth and jawbone. This can lead to severe dental trauma, such as chipped or broken teeth, root fractures, or tooth loss. Using a retainer as a night guard for bruxism can warp the appliance, causing teeth to shift out of alignment and undoing orthodontic work.
Choosing the Right Type of Mouthguard
Selecting a proper protective device depends on the activity, whether for sports or teeth grinding. For high-impact sports, three main categories of mouthguards offer varying levels of protection and fit. Stock mouthguards are the most affordable but offer the least protection due to poor fit. Boil-and-bite mouthguards soften in hot water, allowing the user to mold the device for a better fit and moderate protection. Custom-fitted mouthguards provide the highest degree of protection and comfort, created by a dentist from a precise impression of the user’s mouth.
Night Guards for Bruxism
For bruxism, a different appliance is needed, such as a night guard or occlusal splint. These are designed to separate the jaw surfaces and absorb grinding pressure, protecting the teeth from wear. Individuals with existing orthodontic appliances should consult a dentist or orthodontist to select a custom-fit guard that accommodates their dental anatomy.