gms | German Medical Science

Masticatory dysfunction is presently grouped under the term "temporomandibular disorders" (TMD) and involves the teeth, masticatory muscles, temporomandibular joints, periodontia and associated structures, nerves, ears, neck, head, and spine. Due to the inclusion of cranial and spinal affections, the term craniomandibular disorders appears to be more appropriate, though currently TMD is more widely accepted and hence used in this text. Stress and parafunctional causes such as grinding and clenching can be reasons amongst others. Habits like chewing one's lips or pressing one's tongue against the teeth as well as neurophysiological interaction between dentition, muscles and temporomandibular joints can contribute to TMD. Regarding the etiology of these symptoms and clinical pictures, the approach to the pathogenesis of functional symptoms and diseases has changed in the last few years both in terms of the diagnosis and therapy and also our overall understanding.

In the early days of functional diagnostics, the approach to the etiology was rather unicausal and based on a simple cause-effect relationship:

Malocclusion → parafunction

Parafunction → functional symptoms and diseases due to great stresses on the determinants of the temporomandibular system

However, it has been shown in the last few years that this approach was inadequate for many patients and, especially in patients suffering from chronic pain, even failed to yield any positive results. Similar to other conditions, as for example, chronic back pain, it was recognized that many different factors play a role in the etiology of these symptoms and diseases. Terms such as "biopsychosocial disease" or "multifactorial disease" reflect this perspective. They are meant to demonstrate that both psychic and social factors have an enormous importance in the etiology of TMD in addition to anatomic, physiological, parafunctional and other biological causes. This signifies that the dentist or physician treating TMD patients with chronic symptoms cannot do this alone but must, based on the initial diagnosis, consult other specialists at an early stage, especially pain therapists, neurologists, ENT physicians, orthopedists, physiotherapists as well as psychologists [1]. Also, findings on the neurophysiology of pain, as for example chronic pain, must be included in the diagnostics and therapy. Moreover, pain medicine has taught us that particularly chronic pain is no longer a warning system with an underlying basic causal chain, but that pain conditions involving the temporomandibular system can also establish themselves as an independent disease [2]. Furthermore, for scientific, ethical as well as economic reasons, reliable and validated diagnostic and therapeutic procedures should be used to provide an even firmer basis for diagnostics and therapy.

Correlations between mandibular problems and ear symptoms have been repeatedly described since the 1930's. The most well-known syndrome was the so-called "Costen's syndrome". The physician Costen described a correlation between the loss of dental support zones, several molars for example, and a possible dorsal or cranial displacement of the mandible. According to his theory, structures close to the mandibular joint such as the auriculotemporal nerve and the Eustachian tube might become irritated, thus leading to symptoms such as otalgia, tinnitus, vertigo or dysgeusia. However, this theory has been refuted many times and is today seen as a mixture of different clinical pictures. Hence, the term "Costen's syndrome" should no longer be used for that reason.

Since many TMD patients actually describe ear symptoms - and in this context mainly otalgia - an ENT examination should be performed prior to the dental functional examination. As often the ENT examination yields no pathological findings, the cause is quite frequently not primarily found in the ear but rather in various orofacial structures. A listing is given in Table 1 [Tab. 1]. The basis for these conditions are neurophysiological relationships such as the mutual, sensory innervation of parts of the ears and temporomandibular joints and masticatory muscles. Furthermore, the primary afferences synapse in the same brainstem areas, which may lead to chronification and transmission pain in the case of frequent and intensive nociceptive stimuli. This means that the site of pain and the source of pain no longer coincide and may thus be misinterpreted by the patient and the therapist. This is very often observed in chronic myalgia, as for example masticatory myofascial pain. According to Travell and Simons [3], as well as our own observations, this involves especially the masseter and the medial and lateral pterygoid muscle. However, periauricular complaints can also be caused by chronic pain in the sternocleidomastoid and the posterior digastric muscle.

Ear noise without any clearly definable cause is often associated with diseases of the mandibular region. Reasons for this are anatomical conditions such as mutual innervation of the masticatory muscles and the tensor muscle of tympanic membrane m. tensor veli palatini and m. levator veli palatini through the trigeminal nerve. Some authors conclude from this that disorders like tinnitus and subjectively reduced hearing may be caused by tense masticatory muscles. These assumptions have not been confirmed, but a new study [4] underscores the observation that in contrast to controls, tinnitus patients have significantly more often masticatory muscles and temporomandibular joints that are sensitive to touch as well as painful opening of the mouth. However, there is no immediate causal relation, but a random coincidence can frequently be expected in view of the fact that about 3% of the population suffer from TMD [1] and tinnitus with a prevalence of 14-32% in the normal population. Moreover, both conditions seem to develop or are reinforced in conjunction with times of physical or psychosocial stress. Thus it may be hypothesized that a common source such as stress of varying genesis may be responsible for two different, but not directly related, clinical pictures. While some studies report an improvement of tinnitus after dental therapy [5], [6], [7], [8], another one disputes this claim [9]. Ultimately, there is not yet enough research on the relationship between tinnitus and TMD and it remains controversial for the time being.

Usually, the cause of painful diseases of the maxillary sinus can be easily diagnosed and distinguished from TMD [10]. However, it should be mentioned that chronic myalgia especially of the m. masseter pars superficialis as well as the temporalis muscle and medial and lateral pterygoid muscle can cause referred pain in areas that patients may describe as maxillary sinusitis [3]. An examination with regard to TMD by a specialized dentist can be helpful here to establish the diagnosis [10], [11], [12], [13].

This syndrome caused by an extended stylohyoid process and/or osseous stylohyoid ligament is characterized by neuralgiform earache, sore throat, difficulty swallowing, headache and neck pain, especially with unilateral head movements (Figure 1 [Fig. 1]). It can be confirmed by a clinical hypersensitivity to palpation and an X-ray of the area. Myogenic symptoms involving the posterior accessory masticatory muscles like the digastric muscle or the stylohyoid muscle as well as the sternocleidomastoid muscle should be excluded in the differential diagnosis.

Patients should always be referred to a dentist with specialist knowledge in TMD and functional analysis when the ENT examination yields no pathological findings. It is particularly important here to find out whether the ENT symptoms can be influenced by changes in the mandibular position. If this is the case, an extensive dental examination regarding TMD is recommended. Figure 2 [Fig. 2] shows possible indications for dental referral as well as a diagram of possible diagnostic and therapeutic procedures.

As in all other areas of prevention-oriented dentistry, TMD diagnostics should be subdivided into "basic diagnostics" and "extended diagnostics" [10]. Moreover, "specialized reconfirming diagnostic procedures" are applied in patients with TMD signs and symptoms requiring more extensive causal clarification [14].

The history and extra- and intraoral examination of patients undergoing medical or dental examination or treatment should, for medical as well as forensic reasons, always include a brief functional examination for possible TMD. An orientational examination should be performed with regard to pain in muscles and temporomandibular joints, limitation and deviation of jaw opening as well as instable or disturbed occlusion. In case of pathological findings, their severity can be assessed e.g. according to Jäger (Figure 3 [Fig. 3]) [15], and more extensive diagnostic measures can be initiated (see 3.2).

In patients with suspected TMD, clinical functional diagnostics help to record and document findings on teeth, muscles, temporomandibular joints and associated structures [16], [17], [18]. The main elements are described below to give ENT physicians an overview of the extended dental diagnostics. To a certain extent the dentist can perform the examination as he sees fit. However, there are various slightly different suggestions [19], [10], [20]. The examination forms of the Academy of Functional Diagnostics and Therapy (http://www.AFDT.de) in the German Society of Dental Oral and Craniomandibular Sciences (http://www.dgzmk.de/) first published in 1985 [20] and recently updated by Reiber and Ottl [21] can be helpful as an orientational tool. At any rate, the findings must be documented on a suitable form [10], [20].

3.2.1 History

When the history is first taken, questions should center on the exact localization, start and cause of all major complaints (where, how, when, how often, why). This involves questions on the quality of pain, its frequency and duration as well as possible accompanying symptoms, especially with regard to limitations in mandibular mobility. Other questions should involve fluctuations or spontaneous remissions including aggravating or alleviating factors. Pain scales (e.g. visual analogous scale, VAS) in which patients can describe the actual and average intensity of pain are recommended for its assessment.

An important part of the history contains questions about general medical diseases. Especially diseases in adjacent areas such as sinus and ear as well as rheumatic diseases and orthopedic problems must be recorded because of their obvious impact on temporomandibular disorders, including diseases of the cardiovascular and gastrointestinal system, allergies as well as liver and kidney disorders. It is also necessary to note presently taken medications, since they sometimes have a considerable influence on drug therapy in TMD, which becomes increasingly important again. Trauma, tumors in the craniomaxillofacial region and cervical injuries can be causal factors for TMD and thus have to be ascertained. The history of patients with suspected TMD must not only include questions on alterations of dentures and occlusion temporally associated with the development of main symptoms but also parafunctions or other oral habits. While the above-listed points are generally ascertained, the psychosocial history is usually neglected or even completely ignored. However, there is hardly any doubt today that depression, anxieties or other psychic factors as well as problems at the workplace, family, money problems, ongoing lawsuits, etc. have a considerable influence on the development and treatment of TMD and should therefore be assessed in the extended history.

3.2.2 Localization of pain

Drawings to locate pain, such as head and total body patterns, can be valuable in helping to demonstrate problems affecting the head and other body regions such as projected and referred pain, multiple arthritis, and problems involving the cervical, thoracic and lumbar spine as well as the pelvis. Since the 1960's, drawings of the head and cervical region are thus a regular part of the expanded history in the context of the clinical functional analysis (Figure 4 [Fig. 4]).

3.2.3 Palpation

Asymmetries, patients' posture, facial expression, swellings, etc. should be inspected prior to the actual examination. Mandatory palpatory findings of both the actual (Figure 5 [Fig. 5]) and the accessory masticatory muscles (Figure 6 [Fig. 6]) and temporomandibular joints (Figure 7 [Fig. 7]) are essential for assessing the functional state of craniomandicular structures. The degree of tenseness and painfulness are indicative of TMD symptoms. Palpation of muscles is a difficult examination demanding good cooperation between dentist and patients and also requires both literally and figuratively a sensitive touch - qualities that are regularly demanded from dentists and physicians but are often neglected. Temporomandibular joint noises like clicking, cracking and grinding can be palpated or ausculted.

It should already be mentioned here that clicking in one or both temporomandibular joints is a frequent finding in the total population, though this symptom alone is no indication for therapy unless further dental measures such as orthodontic treatment or prosthetic reconstruction are planned or the psychosocial condition of the patient is severely impaired by it.

The mandatory dental findings should also include a brief periodontal examination (periodontal screening index or similar [22]).

Indispensable for the differential diagnosis are soft tissue findings to exclude, for example oral mucosal diseases or tumors in those tissue as the cause of pain.

3.2.4 Occlusal examination

Even if less importance is given today to occlusion in the development and maintenance of TMD than a few years ago, the results of the occlusal examination still plays a central role in the clinical examination with regard to dental orthopedic stability [23], [24]. Certain malocclusions seem to be more important in TMD. These include an anterior open bite (Figure 8 [Fig. 8]), an overjet larger than 6 mm (Figure 9 [Fig. 9]), and a coincidence of the retral and habitual contact positions, since the joint is in a border position. The absence of more than 4 posterior teeth (loss of posterior supporting zones) also seems to increase the likeliness to develop TMD [25], [26].

Occlusal examination enables, for example, the recognition of premature contacts that may be responsible for a dysfunctional event. Moreover, changes in the tooth and periodontium like excessive tooth wear or recessions associated with parafunctional motion and loading should be assessed and evaluated. In this way, it is often possible to identify co-factors of TMD and initiate the appropriate therapeutic steps. However, it is important to mention that the authors only found an increased coincidence with TMD in the above findings but could not establish a causal relationship.

3.2.5 Brief neurological examination

According to the definition, only diseases of the masticatory muscles, temporomandibular joints and adjacent structures belong to TMD. However, some patients also report symptoms like numbness or allodynia. To determine whether a neurological event is involved in the symptoms, the dentist should perform a brief neurological examination of the cranial nerves (Figure 10 [Fig. 10]). If abnormalities are found in this brief examination, it is often necessary to present the patient to a neurologist or ENT specialist for exclusion diagnostics before continuing dental treatment.

3.2.6 Brief orthopedic examination

Today, there is no longer any doubt about the correlation between the cervical spine and the orofacial system. For this reason and due to the large number of patients with concomitant problems in the cervical spine and orofacial system, an orthopedic screening similar to the brief neurological examination should be performed in the cervical spine, neck and shoulder region [14], [27]. This should include at least a check of head mobility (Figure 11 [Fig. 11]) and associated pain as well as the neck muscles' sensitivity to palpation (Figure 12 [Fig. 12], 13 [Fig. 13]). If abnormalities are detected, the patient should consult an orthopedist and/or physiotherapist for further examinations.

Further specialized reconfirming diagnostic measures in functional diagnostics include psychometric tests (e.g. SCL-90R, Brief Symptom Inventory BSI [28], [29]), recording of intensity and periodicity of symptoms and pain, manual structural analysis, instrumental analytical procedures (occlusion analysis and motion analysis) and imaging procedures (MRI, rarer CT, sonography and scintigraphy).

3.3.1 Manual structural analysis

Manual structural analysis [30] is based on established orthopedic procedures of manual and isometric testing of articular structures and muscles with regard to their loading capacity, mobility and sensitivity. With these tests (also known as "provocation tests" or "manual tests"), it is possible to identify pathological changes in the joints and muscles (Figure 14 [Fig. 14]).

3.3.2 Instrumental functional analysis

Instrumental diagnostics can be grouped into instrumental occlusion examination, instrumental recording of condyle position and motion of the temporomandibular joint [27]. These procedures should be used if a clear diagnosis cannot be obtained by clinical diagnostics or if clinical findings require more precise verification. Occlusion diagnostics in an articulator (chewing simulator) aims at the detection of disorders in static and dynamic occlusion. Clearly determining the state of occlusion is, however, only possible if there is no joint pathology. Instrumental recording of the condyle movement (axiography, pantography) with mechanical or electronic equipment is indicated if motion disorders cannot be decisively assigned to a joint pathology (disc displacement, structural alteration). The underlying disease can be indirectly concluded from the recorded results. During the course of treatment, the effect of therapeutic measures can be assessed by changes in the metric or graphic findings. Moreover, the instrumental motion recordings provide metric data for adjusting individual articulators.

3.3.3 Imaging diagnostics

Imaging diagnostics have fundamentally changed in the last 20 years. Before that time, only diagnostic measures using lateral transcranial X-rays were available for imaging the temporomandibular joint and were replaced primarily by the development of computed tomography (CT) (Figure 15 [Fig. 15] ) and magnetic resonance imaging (MRI) (Figure 16 [Fig. 16]). Even if these procedures are more expensive than transcranial X-rays, they provide more detailed information on the pathological changes in the temporomandibular joint [31].

A CT is indicated when the clinical analysis raises the suspicion of structural changes in the joint surfaces. Examination of the condyle position is also possible with a CT acquired in axial layers. Moreover, other osseous or soft tissue changes like tumors can be detected.

MRI [31] is used especially if, after performing extended diagnostics, disc displacement is suspected but the type and position could not be clearly verified clinically or if a tumor is suspected. If so, T1-weighted images should be made with both closed dentition and a wide-open jaw. In these images, the position of the articular disc in relation to the condyle is usually clearly identifiable in the different planes. In addition, T2-weighted MRI can also be used to identify intraarticular fluids present due to inflammatory processes in the different compartments of the temporomandibular joint.

3.4 Evaluation: diagnostic models

Principally, all anamnestic data and findings should enter into a clear diagnosis. Historically, various all-embracing diagnoses have been introduced for this including orofacial functional disorder, orofacial pain syndrome, myofacial pain syndrome, and mandibular dysfunction syndrome [18], [32]. The term "myoarthropathy" was introduced by Schulte is widely used in Germany [33]. However, only a few years later, Schulte himself found this term to be inadequate for the complex pathogenesis of this clinical picture and expanded the term to "myo-arthro-occluso-neuro-psychopathy" [34].

As a further development using the diagnostic models of Schulte (1980) and Freesmeyer (1993) [27], a group of scientists from German-speaking universities presented a new diagnostic model in 2001, which was based on a division into initial or main, secondary and differential diagnoses [35].

• The initial diagnosis or diagnoses is/are established from the anamnestic data, basic and further diagnostic procedures that are performed during the clinical functional analysis.

• Based on the expanded examination scope of the clinical dental functional analysis, conclusions can be drawn about the secondary diagnoses (Table 2 [Tab. 2]), which supplement the diagnostic subgroups of the global diagnosis of TMD.

• Differential diagnoses (Table 3 [Tab. 3]) are also based on the expanded and further dental diagnostics but mostly require interdisciplinary consultation and therapy and usually exclude the initial diagnosis with their confirmation.

Alternatively, international classifications should be named like the international classification of diseases (ICD-10) [36] or the subgroups 11.7 and 11.8 of the classification of the International Headache Society (IHS), developed in conjunction with the American Academy of Orofacial Pain [37], [38].

If TMD patients with involvement of other medical diseases are treated from a purely dental standpoint and general medical aspects are not considered, it can be assumed that patients will not be treated successfully. Besides patients, in whom a loss of function is of primary importance, this is especially true for patients with chronic pain as a late result of a TMD not previously or successfully treated. That is why interdisciplinary communication is the basis for treatment success.

The therapy of TMD can be divided into the following steps that always refer to the underlying diagnosis: Informing the patient, self-observation, relaxation therapy, behavioral therapy, physiotherapy, pharmacotherapy, therapeutic local anesthesia, splint therapy and stabilization therapy [37], which will be briefly discussed in the following.

The patient should always be informed about the possible causes and correlations in the development of a TMD, so that he/she can develop an understanding of the symptoms, correlations and disease and ultimately influence the course, for example, by self-observation.

Informing the patient will also alleviate fears with regard to the disease and/or prognosis, which often has a positive effect on the clinical picture.

The self-observation [33], "what am I doing with my teeth", should be recommended to patients who suffer from bruxomania (clenching and gnashing the teeth during day and/or nighttime) or masseter hypertrophy. By placing markers ("red dot technique") at work, on the steering wheel or other places of great tension or concentration, the patient should recognize in the first step whether parafunctions exist, and if yes, when they happen (Figure 17 [Fig. 17]). In the second step, the patient should be reminded of "what do I do with my teeth" in order to actively influence the malfunction by relaxing the muscles.

TMD are often attributed to high muscle activity due to clenching and gnashing that can be intensified by physical and psychic stress [39], [12]. Thus, all therapeutic options like autogenous training, progressive muscle relaxation and hypnosis that contribute to muscle relaxation can be used and should be recommended to the patient, since the behavioral aspect of nocturnal bruxism can only, if at all be influenced by these methods.

If the above relaxation techniques are not sufficient, deeper behavioral changes are needed for the patient. Consultation with an experienced psychologist, psychiatrist or psychosomatic specialist is absolutely necessary here [40].

In principle, functional symptoms and disorders of the masticatory muscles and temporomandibular joint can be influenced by physical and physiotherapeutic measures (cooling, heat, massage and exercise) in the same way as other muscles and joints in the body [30], [13]. Thus, they can be prescribed according to the dentist's diagnosis. Treatment should be performed by an experienced physiotherapist specially trained in TMD (Figure 18 [Fig. 18]). Standardized advanced training courses have now been suggested in this area by the Academy of Functional Diagnostics and Therapy (http://www.afdt.de) in the German Society of Dental Oral and Craniomandibular Sciences (http://www.dgzmk.de/) in conjunction with the appropriate physiotherapeutic boards.

The possibilities of pharmacotherapy were not frequently used in the past. Even from todays point of view, in most cases, pharmacotherapy can only be a part of the entire treatment concept. Indications are inflammatory diseases, arthralgias, myalgias, neuropathies, chronic pain and the resultant sleeping disorders.

Differentiated according to their mode of action, the following can generally be used: analgesics, nonsteroidal antiinflammatory drugs (NSAIDs), muscle relaxants, tricyclic antidepressants, corticoids, sleep-inducing and sedative drugs like benzodiazepines and their newer derivatives.

It should be noted that patients must be informed about adverse effects, contraindications and drug interactions not just for forensic reasons but also that they do not discontinue the medication when less severe side effects like fatigue occur. Furthermore, the drug should be selected according to disease symptoms [41] and not according to the "one fits all" principle.

With many drugs, especially analgesics, a time-regulated intake is often more effective than administration on an as-needed basis.

From the dental point of view, occlusal appliances are the most frequently used treatment method, in which the symptoms of TMD can be positively influenced in about 60% to 80% of patients, depending on the study samples [27], [42], [43], [44], [45], [46], [47].

From a clinical point of view, classification into reflex, stabilization and repositioning appliances has proven effective. This classification is based on the existing symptoms, the affected tissue structures (teeth, muscles, temporomandibular joint) and the severity of the disease (acute/chronic).

Reflex appliances (interceptor (Figure 19 [Fig. 19]) [34], miniplast splints, anterior plateau) are occlusal appliances which prevent the habitual tooth contact and thus prevent gnashing and clenching temporarily, which positively influences the resultant tooth and muscle complaints. Reflex splints are indicated for acute symptoms, which can be attributed to an overloading of the involved tissue. Reflex splints are short-term devices, since they may retrigger parafunctions via the absence of tooth contact (preliminary therapeutic contact). For this reason, wearing time should be restricted to 8-14 days.

Stabilization appliances (Michigan splints [48] (Figure 20 [Fig. 20]), centric splints) are splints that create ideal occlusion, i.e. all-round, even and synchronous tooth contact in a physiological condyle position (centric) in static occlusion and an anterior tooth position with disclusion in the lateral tooth region in dynamic occlusion. This ideal relationship should eliminate occlusion disorders that caused parafunction, minimize the load on the affected tissue and balance out positional and loading changes in the temporomandibular joints. Stabilization appliances can be used on a short-term and long-term basis, for acute or chronic symptoms and also in psychic and physiological overloading reactions. Depending on the initial situation, the change in the jaw posture is minimal even after a longer wearing time. Stabilization appliances are the most commonly used occlusion splints in functional therapy.

Repositioning appliances (repositioning splints (Figure 21 [Fig. 21]), decompression splints) are splints used in the treatment of temporomandibular joint diseases like anterior disc displacement with and without reduction, temporomandibular joint compression, retral displacement of the condyle and osteoarthritis [27], [49]. The temporomandibular joint or joints is/are set in a therapeutic position by the splint to support healing and to maintain a symptom-free joint posture.

Repositioning splints can be used on a short-term or long-term basis. In short-term therapy (up to 8 weeks), the splint is worn until a clear alleviation of symptoms occurs. It is then changed into an stabilization appliance. In long-term therapy, the splint is worn until the temporomandibular joint functions have stabilized. It should be worn 24 hours a day, which may be required for several months.

After long-term repositioning therapy, the occlusal contact relationship must almost always be reconstructed either by orthodontic, prosthetic and sometimes maxillofacial surgical measures. Thus, the indication and implementation of such treatment must be particularly well planned and discussed in detail with the patient.

In temporomandibular joint therapy, the repositioning splint is, however, often the only means to balance out and stabilize intracapsular shifts and thus treat the underlying pathological changes. The long-term results are good with regard to the treatment of pain. In contrast, the prognosis for a permanent elimination of joint noises like clicking or cracking due to anterior disc displacement with reduction is controversially discussed.

Selective grinding of the occlusion and restorative procedures for reconstructing a harmonic tooth contact relationship are considered to be definitive functional therapeutic measures [42], [50]. However, these measures should only be performed if a stable condition has been established after appropriate preliminary treatment, for example, with a stabilization appliance. The occlusal correction (selective grinding) of natural teeth should only be undertaken if disorders have been verified both clinically and by instrumental occlusion diagnostics. Selective grinding should be performed carefully in steps and be limited to the enamel of natural teeth. It should also be noted that the vertical dimensions should not be too strongly reduced by the occlusal adjustment. The aim is to establish a stabile contact relationship in static occlusion. In dynamic occlusion, the goal should be a front-canine-guided occlusion or group function, meaning a front-canine-premolars guidance.

Restorative measures are always necessary after preliminary functional treatment, if teeth are missing, habitual occlusion and/or the vertical dimension are/is lost and if the disorders in static occlusion cannot be eliminated subtractively, i.e. cannot be balanced-out by selective grinding (Figures 22-25 [Fig. 22], [Fig. 23], [Fig. 24], [Fig. 25]) [27]. The indication can often only be established after evaluating the individual situation via instrumental occlusal analysis. The aim is to achieve a stable position between the upper and lower jaw in the centric condylar position. It was clinically shown that after extensive reconstructions it is useful to wear them for 4 to 6 weeks on a trial basis to enable a reevaluation in the case of possible shifting of the lower jaw to the upper jaw by remounting the new restorations in an articulator.

It must be taken into consideration that applying such restorative-functional therapeutic measures exceeds by far the degree of difficulty and expenditure for "normal" restorative treatment. Basically, the patient should be in a recall system, so that the restoration can be monitored on a regular basis. After integration of the restoration a stabilization appliance should also be integrated as a long-term splint for the protection especially with extensive parafunctions.

In summary, it can be said that temporomandibular disorders represent a group of disorders that are often temporary and self-limiting and in the majority of cases leave no serious effects behind with regard to restricted function. Epidemiological studies report an increase of the disease in patients between 20 and 50 years of age; thereafter, the incidence seems to strongly decrease. It is possible that TMD are pushed into the background by more severe diseases or there is a reduction of the many still unknown influencing factors.

In any case, these factors should lead us to choose conservative and reversible types of therapy, as they provide a large majority of patients with rapid and long-lasting relief of symptoms. More invasive and irreversible treatments (extensive occlusal reconstructions or even surgical intervention) are only indicated in defined situations after thorough examinations and, in the case of occlusal reconstructions, if a simulation of the effects of this therapy with reversible means proved to be successful clinically. The earlier adequate therapy begins, the greater the chance for a rapid and permanent treatment success and the lower the probability of therapy resistant intractable, chronic pain and/or functional limitations.