The majority of dental practitioners offer standard bite splints for TMJ/bruxing/clenching patients hoping that this will alleviate the patient’s pain and stop parafunctional habits. However, many of the patients that receive orthotics either do NOT wear them or complain that the splints are making them worse. The patients that are referred to our office have had one or several bite splints fabricated and they complain that their symptoms are worsening. This problem may be related to the design of the orthotic. It could also be related to the complexity of the patient’s problems which requires more advanced and complex case treatment management.
First, let’s review the upper bite splint, one of the most popular orthotics made by most practitioners. These splints usually do NOT work, unless they have an anterior bite plane that discludes posterior teeth. A regular acrylic processed or thermoformed upper bite splint that allows lower posterior teeth to occlude on the plastic will usually worsen a patient’s symptoms, especially if they have popping and clicking or more chronic TMJ problems. There are reasons behind this issue. When posterior teeth occlude on a foreign object the neural brain response “subconsciously” activates the trigeminal nerve which in turn elicits more activity in the temporal and masseter muscles. This causes more bruxing and clenching. As humans we are genetically programmed to use our back teeth to chew food in order to start the digestive process. When any object is placed on the back teeth the brain considers it food and wants to chew it and break it down before swallowing. The opposite happens when you put an object between the front teeth. The brain wants to protect the teeth from damage and it tells the muscles to relax by inhibiting the trigeminal nerve. The brain does not want you to chew with your front teeth! This is the reason that NTI devices work best for clenching patients while full coverage splints can exacerbate the problem.
Furthermore, the fabrication of most upper bite splints are made with distallizing contacts which places the lower jaw into a retrusive and harmful trajectory. TMJ patients already have a distallized mandible. Placing an orthotic which further retrudes the mandible will actually make the TMJ issue worse. The majority of upper splints that we see have these wrong designs and lack efficacy. If you see this in your practice you can make a quick change by building up the anterior part of the orthotic (from lateral to lateral) with cold cure acrylic in order to allow only the lower anteriors to contact this new bite plane so that the posterior teeth are discluded. Your goal is to stop the posteriors from contacting plastic. All you need is 1 mm of disclusion…not more! Usually it’s just much easier to fabricate a NTI.
Lower bite splints: can have the same deficiency if they are fabricated with flat planes or biting areas that are incorrectly designed. Lower orthotics can be highly effective if they are fabricated with a neuromuscular design that allows upper lingual cusps to occlude with a mesializing action. Otherwise, they can also worsen TMJ problems. The majority of TMJ patients are treated with neuromuscular designed lower splints!
Soft bite splints: can help during acute pain phases only because they can provide some comfort to the teeth and muscles by taking the biting stress out of them. However, they cannot be used for long term treatment. In fact, if they are used for patients who do NOT have acute muscle pain they can actually worsen the bruxing or clenching problem for the same reasons stated above. They can actually make symptoms worse because the muscles view the soft material as food.
Hard/soft splints: same as above information. Also, these orthotics tend to break down faster as the soft material degrades quicker. They cannot be relined or adjusted easily.
NTI: these are easy to make directly in a patient’s mouth in under 15 minutes. They are highly efficient for clenching and somewhat effective for bruxing. As explained above, the NTI works by the theory that a human does not want to chew with their front teeth in order to protect them from damage and therefore the brain tells the muscles to open the jaw instead of closing it. The fit is critical. If the disclusion of posterior contacts is more than 2 mm the NTI may not work and could even cause more clenching. NTIs cannot be used for chronic TMJ patients who have disc problems. NTI devices cannot be billed to dental insurance because they do not cover all tooth surfaces.
If you are interested in learning more about bite splint design we recommend that you take a TMJ course or consult with us regarding your cases. Patients can lose trust if they are paying for treatment that is ineffective and orthotic design is a critical component.