Occlusal Splint Therapy
TMD or Tempero Mandibular Disorder is a very common affliction that may affect any age group and thorough diagnosis is required to differentiate it from other cranial and facial pain conditions including tension type headaches and migraine although these latter two may co-exist with TMDs.
Why have you been recommended to have an occlusal splint?
An Occlusal Splint is designed to reduce or eliminate symptoms that come from the TMJs (Tempero Mandibular Joints) and/or the 9 pairs of muscles (Masticatory Muscles) that are associated with jaw movement, chewing, swallowing and speech and various social functions.
Most “TMJ” problems are related to the masticatory muscles and not the actual joints themselves.
Hyperactivity and subsequent pain (lactic acid build-up) in the masticatory muscle complex is diagnosed by a thorough assessment of the joint and muscles and the facial pain is called Myofascial Pain Dysfunction. The pathology of this joint and muscle complex is called TMD/MPD.
Your TMJs are unique joints in your body in that two bones fuse together in the midline and the joints themselves are not like a door-hinge that simply rotates unlike some other of your joints.
The TMJs have a complex range of movements including hinge rotation and forward, backward and side-ways sliding.
The position where your Condyles (Head of your lower jaw) sit will vary for you and is determined by two sets of factors.
Normal TMJ anatomy showing:-
- Condyle (Head of the jaw
- Meniscus (Fibrous cartilage disc that separates the two boney surfaces)
- Synovial joint fluid
- Temporal Fossa where the Capsule attaches to the base of the skull
- Lateral Pterygoid Muscle that opens the jaw and moves it around)
- Emenentia Articularis
- Joint capsule that wraps around the joint between the condyle and base of skull
There are two factors that determine where the condyles of your lower jaw (mandible) sit within their joint capsules. Firstly, the position in which your teeth most commonly come together guides the position of the condyles within your TMJs.
Illustrating how the teeth come together like cogs of gears.
The second factor is the 9 pairs of muscles that all influence the jaw position.
Not all are directly attached to the jaw but all influence the position of the condyle within the temporal fossa (the socket in the base of the house where the joint capsule sits. These muscles are collectively known as the masticatory muscles comprise of:
- Medial pterygoid
- Lateral pterygoid
- Posterior digastric
- Anterior digastric
Examination of these, your TMJs and how your teeth meet and move over each-other is called Occlusal Analysis.
In a comfortable bite position, there is harmony between where the muscles act to seat your condyles and the habitual bite position guides into that identical position.
Many factors will influence where your habitual bite position directs your TMJs including heavy grinding and clenching of your teeth (bruxism), chemical erosion from acidic food and drink and from silent reflux, loss of teeth, fillings and crowns and any removable prostheses worn on your teeth.
When the position of the condyles directed by your bite position is different from where your chewing muscles wants to seat it, the masticatory muscle complex may become very painful (MPD) or the TMJs may develop pathology or internal derangement.
Headaches, facial pain clicking the joints, a feeling of wet soggy ears, hearing dullness, vertigo (loss of balance and a feeling of head-spins) or tinnitus (ringing in the ears), neck and shoulder pain and even migraine may result.
The splint is designed to separate the teeth so the shape of your teeth no longer guides the position in which the condyles sit within your temper-mandibular joints.
This just leaves the muscles to guide the position of the TMJ Condyles. When left alone to do this, the muscles find their own happy balance with all of them pulling in different directions. A splint is designed to allow the muscles to find that harmonious position which usually results in a great reduction in the pain and symptoms of TMD/MPD and alleviates most if not all the symptoms.
Regrettably, many dentists just make a splint and expect that to fix the problems fully.
Once a splint is custom made, and its design must satisfy a number of criteria, a very careful balancing of your bite is necessary when the splint is first fitted for you.
Occlusal Splint in position
The splint starts working and, in so doing, the position in which your condyles end up during this Occlusal Therapy will change the position of your lower jaw so that your teeth do not meet the splint in the same position after a week or so.
It is then necessary to bring you back to further balance the contact your teeth make with the splint as these jaw muscles come to a happier position.
Depending on how much discrepancy exists in each case between the habitual bite position caused by how your teeth meet each-other and the balanced most relaxed position that your jaw muscles want to seat your TMJs, there may be a significant period of time during which you will need to return regularly to have your splint adjusted.
This is the normal pattern in the successful treatment of TMD/MPD where a number of adjustments are required before the muscles finally come to a happy balanced relaxed position.
Your splint is usually only worn when you go to bed, so during the day, your habitual bite position guides your jaws and TMJs.
At the point where your jaw muscles have found their most relaxed balanced position, there may, by the, be quite a big discrepancy between where your condyles sit with your splint in and when not in your mouth. At this point, it is usually necessary to adjust the teeth so that the teeth guide you into the same position that your relaxed jaw muscles want your TMJs to sit.
This may be quite a complex procedure which may require a detailed Occlusal Equilibration (ensuring reshaping the teeth so that all those interferences of this harmonious biting position are eliminated) to make those two influencing factors of TMJ position to end up with your condyles both in the same positions of harmony. This may even require extensive rehabilitation of a badly broken-down bite to give your relief from the symptoms of Tempero Mandibular Disorder/Myofascial Pain Dysfunction.
Occlusal therapy may be quite time consuming and ultimately quite expensive and each adjustment visit has a fee involved. Because it is impossible to predict how many visits Occlusal Therapy is likely to take, giving an exact fee in advance is impossible. Most cases do not require more than a few adjustment visits and the Occlusal Equilibration may not be too complex or require crowns or complex fillings.
Following and during Occlusal therapy, certain exercises for your jaws are likely to be prescribed for you to do regularly.
At times, you may be shown a special technique for releasing the tension in certain of your masticatory muscles.
Alternatively, you may be referred to a Physiotherapist with particular interest in TMP/MPD or even to see an Oral and Maxillo-Facial Surgeon for manipulation of your TMJs to break down adhesions within the joint. The OMF Surgeon may occasionally recommend Arthroscopic procedures , procedures to remove fragmented meniscus and bone tissues and rarely even TMJ joint replacement.
As an emergency treatment in cases of very acute TMJ Dysfunction where the joint may be very painful or you cannot open your jaw by more than 2 centimetres, you may require a Rescue appliance like an Aqualizer.
At times, you may be recommended to other Specialists for specific variants of Occlusal Splints designed to reposition a meniscus that is misplaced within the joint capsule.
The Clicking or popping noise that commonly occurs with Internal Derangement of the TMJ.)