occlusion sheet # 11 - Suhiab 3a6eyeh

By the name of Allah
Occlusion lecture # 11
Done by Suhaib Attieh
Second lecture, 25\4\2011
Continuing the temporo-mandibular disorders:
The fourth temporo mandibular disorder: Chronic hypomobility disorders:
* Hypomobility: abnormal mobility of the joint, where it’s less than usual.
It’s a long term (chronic) painless restriction of mandibular movement. Until now all other temporo mandibular disorder are associated with pain, so it’s the only one that isn’t associated with pain (remember chronic disorders aren’t associated with pain).
Pain only arises when trying to force the mandible beyond limitations. For example, when the patient comes to the clinic in a chronic hypomobility disorder in the TMJ & the dentist tries to open the patient’s mouth forcefully to the maximum, which would cause pain.



No associated male occlusion (mostly). Acute male occlusion associated with acute syndromes. But chronic syndromes are associated with adaptation in the occlusion.
Types of chronic mandibular hypomobility:
1- Contracture of the elevator muscles:
The most affected muscles by hypomobility are the elevator muscles.
a- Myostatic contracture:
Muscles are prevented from complete contraction and complete relaxation, that cause pain and if it’s not treated, it would progress to chronic hypomobility disease.
No change in the muscles length and there’s only reduction in the contraction potential.
b- Myofibrotic contracture:
Fibrosis in the muscle tissue dye to injury, therefore the mobility of the muscles is reduced. So the muscles contraction ability is reduced.
2- Capsular fibrosis:
It’s when the capsule or the ligaments around are fibrotic (not elastic) due to a trauma or inflammation which results in permanent restriction of the mandibular movement.
Trauma ------ Hemarthrosis (bleeding of the joint) ¬¬¬----- fibrosis
3- Ankylosis:
It’s the replacement of the hyaline cartilage of the articular surfaces by bone.
The sequence is: trauma (to the joint) ---- Hemarthrosis ----- replacement of the hyaline cartilage of the articular surfaces by bone ---- permanent restriction of the mouth opening.
The fifth temporo mandibular disorder: growth disorders:
Types:
1- Hypoplasia:
Lack of growth in the condyle
Usually with asymmetry (one side is normal & the other is affected) as the baby in the slides.
2- Hyperplasia:
The condyle continues to grow beyond its normal limits.
• To differentiate between hypo & hyperplasia we do a bone scan (looking for the growth centers). So hot spot indicates a hyperplasia. In Hypoplasia, one condyle appears normal while the other one appears small.
• Bone scan: we inject the body with radio fluorescent material that goes to hot sites & appear in the X-ray.
3- Neoplasia:
It’s the presence of a neoplasm (any growth disorder) in the TMJ.
Now treatment modalities of temporo mandibular disorder:
• Symptoms don’t always fit into one classification. When a patient complains from something, doesn’t always indicate a certain disease, which makes it harder to treat.

• Many factors lead to confusion in temporo mandibular disorder treatment:
1- Lack of a scientific evidence for the effectiveness of a treatment. In other words, when the patient is treated for a temporo mandibular disorder, it’s not known what the main factor is, is it the treatment supplied by the dentist? Is it the reduction of the pressure that was on the patient? Is the disorder a self-limited? Or is it the talking to the patient? Many factors cause a temporo mandibular disorder & many affect the cure of it. So it’s not easy to say that this treatment is affective.
2- Some etiological factors (causing factors) contributing to temporo mandibular disorders are difficult to control or eliminate (e.g., emotional stresses). When you are not able to eliminate the cause of the disorder you aren’t able to treat it.
3- Presence of factors that cause temporo mandibular disorder without known treatment.
• The adaptability of the patient increases the orthofunction. Which means when the patient is more adaptable to a problem in his or her mouth, he won’t need a treatment.
• Trauma ----- decreases the adaptability (if patient can tolerate a temporo mandibular disorder in normal situation he won’t tolerate after trauma)
Good nutrition\health ------- increase the adaptability
Coping (the way of dealing with the disorder) -----some people can cope with anything they face (high adaptability); while others can’t cope & they always complain (low adaptability).
Structure of the TMJ also affects the adaptability (ideal TMJ structure will increase the adaptability of the patient, while the presence of abnormal structure will decrease the adaptability of the patient)
Gender (usually females are much less adaptable than males “theoretically” but the reality says that females are more adaptable than males “according to the dr.”& it’s a matter of prevalence. The dr. says also that females are more worried about things, that’s why the go to the doctors not because they can’t adapt, while males don’t care about things). Again the dr. says that she thinks the adaptability of both males & females is the same but it differs in the prevalence.
• Hyper function of the TMJ causes a shift to the Para-function (patho-function or patho-occlusion).
• Life stresses ----- any increase in the stresses increase the probability of hyper function
Sleep disorders (uncomfortable position, clinching on teeth and also the general mood –people don’t sleep that much is at increased risk of stresses-) ----- increase hyper function
Pain \ depression ----- also increase risk of hyper function
Occlusion (interferences for example) ---- increase hyper function
Posture (people who play on violin for example or those who sit on computer for a long period of time putting their hands on the TMJ) ---- affects the TMJ
• These factors aren’t exclusive but they’re of most important.
Modalities of temporo mandibular disorder treatment:
1- Definitive:
Eliminate the etiologic factors completely if we could determine them, which is not an easy thing.
To deal with the parafunction, the dentist should repair any malocclusion and help the patient to eliminate emotional stresses or advice him to go to a Psychologist. Malocclusion or emotional stresses are the most common factors in parafunction.
2- Supportive (palliative):
Alter the patient’s symptoms and has no effect (usually) on the etiologic factors.
Just to deal with symptoms means only to improve the patient’s life by eliminating pain by pharmacological therapy or physical therapy, and it doesn’t eliminate the etiological factor.
• All initial treatments should be conservative, reversible & noninvasive. If the patient didn’t response to the treatment, I’d go to the more invasive options.
First: occlusal therapy (definitive):
• Occlusal therapy ----- aims to change the existing occlusion that we think it’s the cause of the disease.
• Patterns of occlusal therapy:
1- Reversible:
By using an occlusal splint: which is an acrylic applicant worn over the teeth of one arch that has an opposing surface which create and alter the mandibular position and contact pattern of teeth. (Occlusal splint, occlusal bite splint or night guard are common names). It’s worn on teeth so the occlusion is on it & no more on the natural teeth. By this we remove the occlusal interferences which may be the cause of muscle spasm. Again eliminating the occlusal interferences (or any occlusal factor) –and if it really was the etiology- the patient would be better. But if the occlusal interferences weren’t the cause, for example it was the emotional stress; the patient won’t improve that much by the splint so the dentist would have to change the treatment & as we said before determination of the etiological factor isn’t that easy. But usually I must start the treatment actually to determine the etiology of the disease.
2- Irreversible:
a- Selective grinding of the teeth: if localized problem (one tooth for example) has a premature contact.
b- Restorative treatment: if the problem was severe (including the whole arch) we replace (restore) by crowns for example.
c- Orthodontic treatment.
d- Surgical procedure.
Second: emotional stress therapy (definitive):
• One must be aware of stress as an etiologic factor because it’s a very common one. But you can never be sure that stress has an etiological role, so in cases like these, dentist must start in the reversible therapy (which if didn’t improve, won’t harm the patient). If the patient is still having the symptoms that means the cause is emotional stress.
• Stress ranges from a mild condition to a very severe one. Dentist can deal with the mild cases and if suspected a neurosis or psychosis, he sends the patient to a psychiatric.
• Types of emotional stress therapy:
1- Increase patient’s awareness:
To tell the patient that stresses can cause a temporo mandibular disorder and he must stop clinching on his teeth to be cured. Many patients don’t know that stresses can cause a temporo mandibular disorder, and usually clinching occurs at the sub conscious level.
2- Voluntary avoidance:
To ask the patient to avoid parafunctional conditions. For example many patients clinch on their teeth while watching TV, so you advise them to avoid that.
You try to bring the unconscious habits to the conscious level and avoid any parafunction.
3- Relaxation therapy:
To teach the patient how to relax muscles engaged with hypersensitivity.

Third: pharmacological therapy (supportive):
• Giving the patient drugs, like:
1- Analgesics (systemic drugs): to eliminate pain.
2- Tranquilizing agents (systemic drugs): to treat stress. As stress can’t be eliminated, these agents could alter the level of stress. In exams for example many students may take these agents to reduce the level of stress.
3- Local anesthetics (injection locally inside the joint): usually in cases of very acute pain & the patient is no more able to tolerate this pain.
4- Anti-inflammatory agents: very helpful in temporo mandibular disorders because in association to pain we have inflammation.
5- Muscle relaxant.
• Dose must be controlled and for a short duration (because these drugs may cause addiction), and the patient must take these drugs in a proper way.
Fourth: physical therapy (supportive):
• Usually it’s not done by dentist, but instead you send the patient to physiotherapist.
• Types of physiotherapy:
1- Thermotherapy: applying heat packs to the affected area by pain and tenderness.
Way of action: it increases the blood circulation, which decrease pain.
2- Coolant therapy: applying something cold like ice cubes or ethyl chloride spray.
- Ethyl chloride spray acts as a mild topical anesthetic by its chilling effect when sprayed on skin, such as when removing splinters in a clinical setting. It’s sprayed also on muscles, during football matches for example to reduce pain after injury.
- Spraying should be away from the patient, and the spray shouldn’t reach the eyes or the nose. In addition to that it should be avoided in any patient with cardiac problems because it’s a potential cardiac inhibitor although it’s applied as a spray.
- Thermotherapy & coolant therapy could be done at home. And their effect is superficial.
3- Massage therapy: applied to eliminate muscle spasm.
4- Electrical stimulation therapy: if the involved muscles are deep (lateral & medial pterygoid for example), where thermo & coolant therapy aren’t affective we apply electrical stimulation.
- Mechanism of action of electrical stimulation: we put electrodes on the face to cause rhythmic contraction of the muscles & relaxation like doing an electrical massage. This increases the range of movement.
- EMG that is used in the diagnosis of temporo mandibular disorders differs from Electrical stimulation therapy. It’s like the ECG and it gives a reading to the muscles activity, but Electrical stimulation is a well induced contraction that leads to the relaxation of the muscles.
5- Relaxation therapy: a very common category in treating temporo mandibular disorders.
Specific treatment of temporo mandibular disorders:
First disorder: treatment of acute muscle disorders:
• Etiology: could be trauma, occlusion or stress.
1- Definitive treatment:
a- Eliminate the etiological factor if identified. For example if the cause was a high filling, you can correct that, because you know reducing the filling to the normal will solve the problem. One of the ways to predict the etiology of the temporo mandibular disorder is taking history from the patient, for example, if he went to a dentist lately he might have a high filling, or if he had a trauma it could be the cause.
b- Reversible occlusal therapy (occlusal splint):
I. It eliminates any premature contact.
II. It stretches and then relaxes the muscles.
c- Irreversible occlusal therapy: if the problem involves more than one tooth, I may establish an orthodontic, prostatic or surgical treatment
d- Emotional stress therapy.
2- Supportive therapy:
a- Restrict the mandibular movement to the painless level. Increasing the pain will increase the muscle spasm (positive feedback, pain---spasm---pain---spasm---etc), so decreasing pain will lead to decrease the muscle spasm.
b- Instruct the patient to eat a soft diet & use small bites to avoid muscles overloading.
c- Analgesics and anti-inflammatory drugs.
d- Muscles exercises aren’t indicated since they can elicit and aggravate cyclic myospasms. Muscles exercises could be established after the elimination of pain to restore the full opening of the mouth.
• If the treatment hasn’t resolved the symptoms in 10-14 days then myositis is likely to be present. We treat it be long term behavioral modification such as progressive relaxation & biofeedback training.
• Progressive relaxation by emotional stress therapy.
• Biofeedback training by giving the patient an EMG devise (which is used in the diagnosis of temporo mandibular disorders) and tell him to watch it. By this the patient can see when he is stressing on his muscles and can stop clinching.
Second disorder: disc interference disorders:
1- Definitive treatment:
a- Directed toward achieving a more normal disc-condyle relationship.
b- Biting down on a separator. As we said in disc interference disorders the condyle presses on the retro-discal area which is a very sensitive area, so by biting on something that separates the teeth, the patient will feel the relief of intra-discal pressure, therefore less forces on the retro-discal tissues and so less pain. It’s an immediate treatment and helps in the diagnoses.
c- Occlusal CR (centric relation) bite splint. We make the bite splint in the centric relation not centric occlusion because it’s a reproducible relation and the most normal (relaxed) position of the joint.
- Most occlusal splints are built in centric relation.
d- Anterior repositioning splint (ARS). In cases where the disc is anterior to the condyle and centric relation bite splint isn’t working. Because I can’t deal with the disc, I must change the position of the condyle by biting in a protrusive movement; by this the condyle is exactly on the disc. It acts by preventing the lower incisal edges from going posteriorly (locking in anterior position) and thus capturing the disc-condyle position. On the long term, by capturing the disc, it will decrease the inflammation. After that we reduce the splint gradually, hopefully that both (the condyle and the disc) will go back together, and if they didn’t get back together I must do something else like surgery or repeat another period of treatment.
- ARS usually worn for a long period of time (2-4 months).
e- Surgery as final treatment.
2- Supportive treatment:
It aims to eliminate pain as the supportive treatment of muscle disorders.
Third: inflammatory disorders of the TMJ:
1- Definitive treatment:
a- The condition usually is self-limiting if trauma is the cause (external synovitis and retrodiscitis). After trauma the inflammation occurs then gradually starts to disappear.
b- Anti-biotic treatment in cases of infection (synovitis and inflammatory arthritis).
c- Anterior repositioning splint (ARS) in cases of retrodiscitis due to internal trauma as we said in a previous point. So ARS is used to solve two problems, disc interference and retrodiscitis.
d- Surgery as one of the last choices.
e- Occlusal splint to decrease overloading for degenerative joint diseases. In degenerative joint diseases we have increased muscles activity which makes overloading on the joint so I may use an occlusal splint to relax the muscles and decrease the load.

2- Supportive therapy:
a- Limit mandibular movements to the painless limit.
b- Soft diet and small bites.
c- Analgesics.
d- Thermotherapy 4-5 times a day. Usually heat packs are applied for 10-15 minutes while ice packs are applied only for 4-5 minutes.
e- A single injection of corticosteroids to the capsular tissues in cases of external synovitis and retrodiscitis. Multiple injections might destroy the joint.
f- Inter maxillary fixation (IMF) to treat acute male occlusion resulting from retrodiscitis. IMF connects the maxilla to the mandible and limits the mandibular movement until inflamed tissues are healed from retrodiscitis. We apply it for a short period of time and the patient must remove it at least 1-2 hours during the day to eat and not to cause Ankylosis (any permanent restriction of the mandibular movement causes Ankylosis).
Finally: how to fabricate an occlusal splint?
Primary impressions ---- build up the models --- set up the incisal table according to protrusive condyler guidance of the patient (anterior guidance) --- set up the lateral condyler guidance --- then we create a space for the splint (around 2-3 mm in thickness) (less than 2 mm the splint won’t dis-occlude the teeth so it won’t work properly) --- after that we put a wax sheet between the teeth --- posteriorly I only want the buccal cusps (of lower jaw as in the figure in the slide number 13) to occlude on the splint (increasing the occlusal spots by palatal cusps occlusion would increase the stresses and cause pain. Explanation, as we increase the occlusal spots we spread the forces more, so we need more forces in occlusion to feel it (to stimulate pain threshold in the periodontal ligament), this increase in the force would cause stress and pain). So it’s better to have less separate points but it should be balanced points (on functional cusps of different teeth) --- anteriorly during protrusive movement anterior teeth should be edge to edge, and during lateral movement there should be a canine guidance. These relations anteriorly and posteriorly should be in the splint even if they were not in the patient’s mouth.
Occlusal splint would overlap the incisal one third (2 mm) of the labial surface of the teeth and overlapping the whole lingual or palatal surface and up to 6 mm of the alveolar bone.
Occlusal splint usually made on the maxilla because it’s easier, more stable & more retentive.
In the last slide there’s a picture to what happens in anterior positioning splint (APS). The rim (of the splint) prevents the patient from retarding the mandible, so the condyle stays on the articular disc and it’s prevented from going to the retrodiscal position. And as we said before we remove the APS by gradual grinding until we reach the zero. But if the dentist removes the APS suddenly, the patient would have an open bite posteriorly which is a disaster (the patient is no more able to eat and there’s no function on the posterior teeth) so we do it gradually.