Bruxism is not a new condition. Literary references date back centuries. Early treatment focused on the mechanism of bruxism but later treatment centered more on psychological issues like anxiety and stress. Today, these two opinions are largely combined. Bruxism has been studied in sleep laboratories, where brain activity, cardiac function, muscle activity, and breathing are monitored. Most clinicians regard bruxism as a sleep disorder that is diagnosed using specific criteria. As such, it is often referred to as sleep bruxism (SB), but bruxism can be a diurnal habit as well, which requires a slightly different treatment approach. These understandings have created a change in how oral appliances are used to manage bruxism.
Initially, bruxism appliances were regarded as temporary measures that enabled clinicians to analyze and improve dental relationships in order to treat the disorder. Potential treatments included orthodontics, malocclusion treatments, and restorative dentistry. Now we understand that bruxism appliances are designed to protect the teeth and hopefully reduce muscle activity during sleep.
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Unwanted Consequences of Bruxism
Chronic bruxism can cause a range of symptoms that include the following:
- Mild or severe tooth wear
- Gingival recession
- Masticatory muscle pain
- Temporomandibular disorders
- Fractured teeth or restorations
Additional symptoms include temporal headaches or migraines, insomnia and depression, tinnitus, and limited jaw opening. The forces generated during bruxism can be up to 6 times the force generated by normal mastication which is generally 162 pounds per square inch.
Patients diagnosed with SB can frequently be treated with bruxism appliances, but treatment may be challenging for the patient and the clinician. SB is tricky to diagnose because the symptoms vary. Occlusal splint therapy provides diagnostic information, allowing the muscles in spasm to relax while protecting the teeth and jaws from bruxism. These devices can also reposition the condyles and jaws into centric relation. Bruxism appliances do not prevent bruxism; they are designed to distribute the force across the masticatory system. Using bruxism appliances can decrease the frequency of bruxism episodes but not necessarily their intensity.
Determining Which Bruxism Appliance Should Be Used and When
The type of bruxism appliance or splint utilized during treatment depends on the clinician’s diagnosis. Dental and medical history must be assessed alongside a comprehensive examination, particularly for bruxism patients with TMD or facial pain. Most bruxism appliances are made in the dental lab and fabricated from a hard or soft acrylic material that provides either a hard or a soft occluding surface. Some softer bruxism appliances are fabricated using thermal sensitive material that is heated in hot water before use. Other appliances have a hard shell and a smooth occlusal surface.
Determining When to Use a Hard or Soft Bruxism Appliance
It’s difficult to determine whether using a hard or soft bruxism appliance significantly affects the treatment outcome.
Hard acrylic bruxism appliances are fabricated with a flat occlusal surface, ensuring even contact with the opposing arch.
Soft bruxism appliances are also fabricated with a flat occlusal surface that can be lightly indexed according to the clinician’s preference. A night guard’s softness can be customized to increased the patient’s comfort. Soft bruxism appliances may be more suitable for children who still have dental bone growth or when the appliance is only required for a short period. Even if the appliance doesn’t result in any appreciable changes in nocturnal behavior, it will still protect the dentition.
When the patient is diagnosed with bruxism but doesn’t have signs of TMD, they will most likely benefit from a full coverage bruxism appliance with acrylic covers that completely protect the entire arch of teeth. The choice of which arch to cover depends on the patient’s bruxism habit. Bruxism appliances may be fabricated to fit the maxilla or mandible, although particularly thick maxillary night splints may be contraindicated in patients with sleep breathing disorders such as sleep apnea.
When the patient clenches isometrically, the most appropriate bruxism appliance is a maxillary night guard that keeps all the teeth in contact and provides full coverage. If a mandibular splint is used, then the force created during clenching won’t be distributed appropriately. When the patient has the power of movement in protrusive and lateral directions, a bruxism appliance for the mandibular arch may be more appropriate. With lateral para-functional movement, a mandibular splint that doesn’t touch all the anterior teeth is appropriate, provided it touches the cuspids for guidance. If mandibular movement during the night isn’t definite, a maxillary bruxism appliance is preferable.
Determining the Occlusal Thickness of the Bruxism Appliance
Determining the appropriate occlusal thickness increases the efficacy of treatment. Occlusal splints that increase the vertical dimension between 4.4 mm and 8.2 mm produce better muscular relaxation in patients with bruxism and myofascial pain compared with splints of 1 mm. It may be preferable to begin with a minimum thickness of 4 mm initially and monitor the patient for continued signs of muscle tightness, headaches, or soreness immediately after awakening. If the symptoms continue, consider increasing the occlusal thickness of the bruxism appliance incrementally until the symptoms disappear.
Bruxism appliances should be monitored continually and adjusted as required to ensure equal contact on all teeth. Eventually, when inflammation subsides, and muscle relaxation is achieved, the position of the teeth on the splint changes. Ideally, neuromuscular harmony is achieved when the patient’s bite is readjusted and rebalanced into centric relation. Continually eliminating any interferences on the bruxism appliance by adjusting the occlusal surface will help rebalance the bite into a centric relationship, providing the patient with long-lasting relief from the symptoms of bruxism.
Mini deprogrammers are made from hard acrylic and have a bite plate covering the upper centrals so that the posterior teeth do not occlude. Deprogrammers work by removing all occlusal interferences. Their design reduces the muscle contraction force while allowing the lateral pterygoid muscles to relax, so the temporomandibular joints are comfortably seated.
Bruxism appliances are useful in managing SB and provide patients with a conservative and palliative treatment approach. Their use prevents or limits damage to the teeth and any dental restorations, but they will not stop people from para-functional activities during sleep. Sometimes SB may seem to disappear for weeks or months, or tooth grinding and masticatory muscle activity may diminish, especially after initially using a bruxism appliance.
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