A mouthguard is a protective dental appliance, typically made from a flexible material, designed to cover and cushion the teeth and gums. While the upper teeth are the standard placement, a mouthguard can absolutely be worn on the bottom teeth. This lower arch placement is usually reserved for specific circumstances where an upper guard is impractical or less effective for the patient’s needs. The decision to use a lower guard is carefully determined by a dental professional based on the individual’s oral anatomy and the condition being treated.
Specific Reasons for Lower Arch Mouthguards
A lower arch mouthguard is often indicated when a patient has fixed dental appliances on their upper teeth. Individuals with upper fixed retainers, bridges, or braces may find an upper guard too bulky or that it compromises the appliance’s integrity. A lower guard is then the preferred option for protection during sports or from bruxism. Patients with extensive dental work, such as crowns or implants, on their upper arch may also benefit from a lower guard to avoid placing excessive pressure on those restorations.
Lower guards are also frequently used in the management of temporomandibular joint (TMJ) disorders. Certain splints designed to reposition the jaw, known as mandibular advancement devices, must be placed on the lower arch to effectively stabilize the joint and relieve pain. Furthermore, for individuals who experience a strong gag reflex, a lower guard is often more comfortable because it does not contact the sensitive palate area. In cases of severe upper tooth loss, a lower guard might be chosen because it provides a more stable foundation and better retention.
Differences Between Upper and Lower Arch Guards
The upper arch is the default placement for most protective mouthguards because the upper jaw provides a larger, more stable surface area, contributing to better retention. This stability means the upper guard is less likely to become dislodged during impact or sleep. A lower guard must contend with a smaller surface area and the constant presence of the tongue, which affects how securely it stays in place.
The relationship between the mouthguard and the tongue is a significant functional difference. While a lower guard can sometimes feel less intrusive to the gag reflex, it may initially interfere more with tongue movement, potentially affecting speech or swallowing. Conversely, an upper guard allows the tongue to move more freely. In cases of teeth grinding (bruxism), the guard’s precise effect on the bite alignment is paramount, and a lower guard requires accurate fabrication to ensure the jaw closes correctly against the material.
The precision required for a lower guard is particularly high because it dictates the final position of the mandible against the maxilla. Unlike the upper guard, which cushions the lower teeth, a lower guard must be designed to guide the upper teeth into a specific, therapeutic relationship with the appliance. This difference makes the customization process for a lower appliance highly sensitive to the patient’s unique bite pattern. The smaller physical profile of the lower jaw also means that the guard must be carefully trimmed to avoid irritating the surrounding soft tissues, such as the floor of the mouth.
Ensuring Proper Fit and Comfort
The effectiveness and comfort of any mouthguard, especially a lower arch appliance, depend entirely on a precise fit. Professional consultation and custom-fabrication are superior to over-the-counter options like boil-and-bite guards, which offer generalized protection. A custom guard is made from a dental impression, ensuring it conforms exactly to the contours of the teeth and gum line.
When the guard is seated, it should snap firmly into place without requiring the user to clench or bite down to keep it retained. The dental professional will check for proper articulation, ensuring the opposing upper teeth meet the guard’s surface in a balanced way that does not strain the jaw joint. Patients wearing a new lower guard should anticipate a brief period of adaptation, which may include temporary lisping or an increase in salivation.
Regular maintenance is important for lower guards, as their proximity to the floor of the mouth can mean increased accumulation of saliva and debris. The appliance should be cleaned daily with a soft brush and non-abrasive soap or a denture cleaner to prevent bacterial growth. If the guard causes persistent soreness, shifts out of place easily, or creates a feeling of an unbalanced bite after the initial adjustment period, the patient must return to the dentist for assessment and potential adjustment.