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Date: 5th Mar. 2018
In day-to-day dental practice there are many patients who have bite problems. Some have a constant soreness in the temporomandibular joint area while some others complain of restorations or prosthetic options that continuously fail.
Trying to treat these patients successfully and retaining them in the practice can be a bit of a challenge. This is where muscle deprogrammers are used to manage patients suffering from these problems. Deprogrammers are devices when worn opens the patient’s bite and allows only a single point of contact just behind the upper central incisors.
Deprogrammers are used to reduce or relax muscle activity levels to eliminate muscle pain or tension. This allows for accurate examination of the relationship of maxilla to mandible with muscles relaxed and condyles in a fully-seated position.
The muscle we are referring to are the lateral pterygoid, which is programmed to position the mandible to avoid pain and posterior interferences in the arc of closure.
If a deprogrammer is in place anteriorly, this muscle will automatically relax since it is no longer in a position to hold the mandible, and thus it avoids posterior tooth contact. Most patients benefit from this mechanism but there are exceptions to the rule.
That’s because there are some patients for whom other stimuli are sent from the brain to the lateral pterygoid muscle which override all other stimuli. For example, there could be patients who suffer from gastric reflux, airway issues, or mental tension which causes changes in the heart rate, brain activity, and ultimately the muscles of mastication.
These patients will show wear and tear on their anterior teeth as well. For example – there could be wear on the palatal surface of the upper anterior teeth and consequently, wear on the buccal aspects of the mandibular anterior teeth, and subsequently, mobility or migration of the maxillary teeth.
In patients who have nocturnal or daytime bruxism, it is very difficult to get good results using a muscle deprogrammer. Thus, if mental stress is the reason for clenching and grinding the teeth, then these issues need to the addressed. If there is a restorative or a prosthetic job done which has unfavourable occlusion, then it must be rectified immediately to provide relief from bruxing.
What happens in these patients is that the lateral pterygoid muscle goes into a spasm, stuck in a contracted state. When these patients go to bed at night, the bite is fine but when they get up in the morning they get a lot of pain when they try to bite on their back teeth. In such patients, a posterior-only appliance provides some comfort, and eventually, the occlusion returns to normal as the pterygoid muscles release and allow the mandible to retrude.
If these patients are given an anterior appliance, we expect the condyles to seat and the mandible to retrude. But, sometimes only the anterior teeth contact on one day and once the appliance is removed, the posterior teeth contact. This happens also because these patients received signals from the brain which override all other stimuli resulting in a variable history.
The answer is to use a leaf gauge to make the bite record, assuring less risk of them posturing the mandible forward. Following these, a custom incisal guide table can be made from their mounted models using their existing pattern of wear to help in setting up the anterior occlusal relationship and give them adequate freedom of movement.
In this, the litmus test is carried out with the provisional restorations. This becomes the testing ground to know whether the anterior functional relationship obtained by the clinician is acceptable or not.
In these patients, the use of flat deprogrammers like a lucia jig or a flat anterior stop has risks. This is because it’s easy for these patients to bite forward on the deprogrammer, which can be interpreted by the clinician to be the position at which the intercuspal occlusion has to be built. However, that’s actually the position where the anterior freedom of movement has to be built on.
These patients provide a challenging situation to the dental specialist from most branches of dentistry. This is because despite following all the protocols carefully, the dental fillings may chip out, ceramic crowns may be destroyed, post and cores done may fracture, prosthetic parts of implants may get damaged.
Muscle Deprogrammers bring about nearly immediate relief of acute symptoms, many times within one to two hours. The added bonus is that supportive therapy like muscle relaxants, analgesics, and other drugs are not necessary. This happens due to a forced relaxation of the muscles of mastication, which in turn, relieves pressure on all anatomic structures including the temporomandibular joint, muscles of mastication, teeth, and the supporting structures.
There is also a shift in the position of the lower jaw leaving the joints in a more relaxed forward position, which probably is closest to the patient’s own centric relation. Thus, the condyles occupy a more centric and relaxed position in the fossae. This position is reproducible without the forceful manipulation of the dentist.
