There are many factors that can cause damage to the temporomandibular joint (TMJ) structures or impair normal functional relationships between condyle, disc and eminence. The main symptoms associated with TMJ dysfunction are pain, limited mobility of the mandible, spasticity of the masticatory muscles and sound that is produced in the joint during mandibular movement. Pain originates from nociceptors located in soft tissue of the joint. If the soft tissue structures are not in inflammation, the pain is sharp, sudden and intense tightly connected to the movements in the TMJ. If the inflammation is presented, the pain is constant and increases with the movements in the joint. TMJ dysfunction is manifested by feeling stiffness of the joint, limited and/or altered opening of the mouth with deviation or deflection of the mandible. Individual or multiple sound produced by the TMJ are most often the consequence of the disturbed function of the condyle-disc complex, the morphological incompatibility of the joint surfaces or degenerative changes in them. The signs and symptoms of disease and dysfunction of TMJ are different and depend on the duration of the disorders and its chronicity as well as on the individual sensitivity of the patients. Proper identification of symptoms and precise diagnosis are therefore essential for future treatment.
- internal disorders
Temporomandibular joint (TMJ) is susceptible to various diseases affecting other synovial joints. Due to its position it is exposed to trauma, and its functional link with the occlusal complex which makes it very sensitive to any occlusal disorders. Any force that overloads the TMJ complex can cause damage to the joint structures or disrupt the normal functional relationship between condyle, disc and articular eminence, resulting in dysfunction or pain, or both. Systemic joint disorders may also affect TMJ.
Diseases and functional disorders of the TMJ can be globally divided into several categories:
deviations in the form of articular surfaces,
disorders in the functions of the condyle-disc complex,
inflammatory diseases of the TMJ,
degenerative TMJ disorders,
ankylosis of TMJ.
This classification is based on the recommendations of the American Academy of Orofacial Pain 1993 .
The basic symptoms that accompany the diseases and dysfunction of TMJ are: pain, abnormal jaw movement, spasm of masticatory muscles and joint sounds produced by the joints during mandibular movements .
The pain that origins from any joints including the TMJ, is called arthralgia.
Arthralgia is triggered by receptors located in the soft tissue of the joint. Such receptors (nociceptors) contain discal ligaments, retrodiscal tissue and articular capsule. Arthralgia from the soft-tissue structures of the non-inflammatory joint represents a sharp, sudden and intense pain that is closely related to the joint movements. If, however, the inflammation of the soft-tissue structures of the affected joint has occurred, the pain will be constant and increase during mandibular movements. Course of pain can be acute or chronic .
Disturbed joint function is a common accompaniment to all joint disorders. TMJ dysfunction can occur in various forms but their major effects are the limitations and/or alterations of jaw movements. This is manifested by the feeling the stiffness of the joint, limited mouth opening with deviation or deflection of the mandible on the affected side and limited movement to the contralateral side [2, 3].
The sound signals produced by the joint are the most common consequence of the dysfunction of the condyle-disc complex, the morphological incompatibility of articular surfaces and their degenerative changes. The sound signals produced by the joint may occur as individual short-duration sounds at opening or when opening and closing the mouth, referred to as clicking (“click”) or as multiple, rough and scratched sounds, which are called as “crepitation” [2, 3].
2. Deviations in the form of articular joint surfaces
2.1 Defects on the articular joint surfaces
The most common defects on the articular joint surfaces occur in the upper joint compartment and affect the articular eminence or the upper surface of the disc, thus preventing normal translatory movements.
Deviation can be followed by clear single sound—“click”, followed by normal opening or closing of the mouth. The click always occurs at the same level of opening or closing motion and should be distinguished from the reciprocal click in patients with disc displacement with reduction. In the disc displacement with reduction click is rarely heard at the same level of opening or closing the mouth [2, 4, 5].
2.2 Thinning of articular disc and perforation of disc
3. Function disorders of condyle-disc complex
3.1 Disc derangements (mechanism of disorder)
These disorders are series of dysfunction that are most often the result of previous diseases, trauma, or occlusal disharmony. Disorders are caused by changes in the relationship between condyle and disc and the disturbance of their functional activity. In the normal joint the disc is bound to the medial and lateral condyle pole by discal ligaments. Therefore translational movement in the healthy joint is possible only between the condyle-disc complex and the articular eminence. The only physiological movement between condyle and disc is rotation. The amount of rotation of the disc in normal circumstances depends on the shape of the disc, the degree of interarticular pressure and the synergic function of the upper head of the lateral pterygoid muscle and the upper layer of the bilaminar zone [2, 10, 12, 13, 14, 15, 16].
In opening the mouth and moving the condyle-disk complex forward, the upper layer of the bilaminar zone is tensed and retracted (rotates) the disc in the posterior direction. The interarticular pressure increasing during the mouth opening maintained the condyle below the thin intermediate zone of the disc and prevented the thicker anterior disc border from being pulled between the condyle and eminence.
The upper layer of the bilaminar zone is the only structure that can pull the disc backwards. This force only works when the condyle is moved forward and it extends and tightens the upper layer of the bilaminar zone. There is no tension in the retrodiscal tissue during the closing of mouth. The disc rotates forward thanks to the function of the upper head of the lateral pterygoid muscle, when the mouth closing. This muscle part is activated and pulls the disc forward, while the condyle-disc complex slides back and up. The moderate rotation of the disc, which occurs in the normal joint under the mechanisms described, allows the disc and condyle to remain in intimate contact during all movements and all mandibular positions. In the healthy joint, the articular surfaces of the condyle, disc, and eminence are smooth and sliding, which ensures unobtrusive movements without any friction. The normal relationship between condyle and disc in mandibular movements is also maintained due to the specific form of disc.
The biconcave form of the disc and its thickening borders itself ensures the stability of the disc condition while the interarticular pressure increases during the opening of the mouth also helps to center the disc on the condyle. Medial and lateral discal ligaments support the maintenance of disc because they avoid any translatory movement between condyle and disc [2, 10, 12, 13, 14, 15, 16].
If, however, the form of the disc is changed and the discal ligament is elongated, the translatory movement between the condyle and the disc becomes possible. The amount of this movement depends on the change in the form of disc and the degree of elongation of discal ligament. Discal ligaments are not elastic and after elongation they retain that length.
Under the closed mouth, interarticular pressure is very low. If the disc ligaments are stretched, the disc can move on the articular surface of the condyle. Since in the closed mouths the upper layer of the bilaminar zone has no influence on the position of the disc, the tone of the upper head of the lateral pterygoid muscle may influence the disc to assume the anterior position on the condyle. Moving the disk forward is medially limited by the length of the discal ligaments and the thickness of the posterior disc border. If this condition lasts longer, the posterior disc border can be thinned, making it easier for its antero-medial dislocation. In such cases, the articular surface of the condyle no longer rests below the intermediate zone of the disc during closing mouths, but under its thinned posterior disc border or, even in the retrodiscal tissue.
This condition is referred to as a functional derangement of the disc and is initially difficult to register. Later, there is a pain, usually associated with chewing. If the anterior displacement of the disc is more pronounced, the joint function may be compromised. During the mouth opening, the condyle moves forward, a short translatory movement between the condyle and the disc is performed first, ensuring that the condyle takes its normal position below the intermediate zone of the disc. This relation of condyle and disc is then maintained during the further opening of the mouth under the action of interarticular pressure which increases at the opening of the mouth.
During the closing of the mouth the fibers of the retrodiscal tissue actively assist in restoring the condyle to the normal position, which it occupies when the mouth is opened. The interarticular pressure maintains intimate contact between the condyle and the disc during the translational closing movement and does not allow the anterior, thicken disc border thread between the condyle and the articular eminence. However, when the closing movement is complete, the interarticular pressure decreases and the tension in the retrodiscal tissue is reduced, the tone in the upper head of the lateral pterygoid muscle will have an effect on the anterior displacement of the disc [2, 10, 12, 13, 14, 15, 16].
The basic characteristic of this functional disorder is the presence of translational motion between the condyle and the disc at the beginning of the opening and at the end of the mouth closure, which does not exist in the normal joint. During this pathologic translation, increased interarticular pressure or deformed articular disc may prevent undisturbed crossing of articular surfaces. This raises the sudden, distorted movement of the condyle that skips the barrier to take normal position below the intermediate zone of the disc. This sudden skip of the condyle motion usually accompanies a characteristic sound, which is referred to as a “click” at the mouth opening. After this sound, normal relation between condyle and disc is established during further movement of the opening.
This condyle-disc interact is presented during mouth closing all the way till the very end. However, when the mouth is closed and the interarticular pressure decreased, the disc is again displaced forward (and medially) under the tone of the upper head of the lateral pterygoid muscle.
If the displacement is small this shift is usually not followed by a characteristic sound. A single “click” at the mouth opening indicates an early stage of dysfunction.
If the condition is prolonged, the dysfunction is increased. Continuously anteriorly displaced disc leads to permanent elongation of the discal ligaments, including the lower layer of the retrodiscal tissue. The posterior disc border continues to thinning, and the condyle lies practically on the retrodiscal tissue when the mouth closed. Morphological changes in the disc in the area where the condyle is now positioned may cause a secondary “click” in the final stages of closing the mouth just before the condyle takes the final position. Disc is most often moved forward, or anteromedial, but it also appeared the medial, lateral and even posterior displacement of the disc. Displacements of the articular disc represent a series of pathological conditions that progressively worsen over time. These conditions usually begin with disc displacement with reduction, which is usually not accompanied by pain or major function disorders. In some patients, this condition aggravates, takes a heavier form of dysfunction, disc displacement without reduction, while in others the level of the displacement of the disc is prolonged for long time (Figure 1). The reason for these differences is not always clear. The presence of various factors that may contribute to the development of dysfunction, such as loss of lateral teeth, systemic stability of the ligaments or the presence of parafunctional activities, has certainly a significant influence. In diagnosing disc displacement, clinical examination is not always sufficient to determine the actual condition, especially in cases where dysfunction does not cause greater discomfort. Special X-ray techniques, such as arthrography or MRI, are often needed to confirm a clinical diagnosis. However, it must be emphasized that the painless joint with mild mouth signaling is not an indication of the use of complicated and expensive X-ray methods. The clinician must determine whether arthrography or MRI is crucial for determining the correct treatment [8, 9, 10].
3.1.1 Disc displacement with reduction
In this disorder when the mouth is closed, disc does not take a normal position between condyle and articular eminence, but is displaced forward, or forward and medial, and during opening of the mouth it returns to approximately normal position on the condyle [2, 10, 12, 13, 14, 15, 16, 17]. In some cases, this may be accompanied by increased muscular activity, pain, and limitation of mandibular movements.
The following clinical sign that can be easily detected in these patients is the deviation of the middle line of the mandible to the affected joint at the earliest stage of mouth opening. This is because of the temporary blockade of condyle translation caused by disc displacement. When the disc takes a normal position in relation to the condyle, during mouth opening, the translational movement forward and down as well as the middle line of the mandible return to normal. The deviation from the deflection of the mandible should be distinguished. Deviation is the initial turning of the mandible to the affected joint due to a temporary obstacle. The mandible returns to the central position when the obstacle passes (Figure 2). In the deflection, the middle line of the mandible moves from the beginning to the end of the movement of the opening to the affected side and does not return to the center (Figure 3).
Pain is not always a companion to the anterior disc displacement. If present, it is usually stimulated by tensed disc ligaments or it is caused by the condyle pressure on the retrodiscal tissue.
The amount of mandibular movements in this disorder is usually normal and in fact the diameter of the maximum opening of the mouth may be greater than normal. Limited opening of the mouth, if present, is the most common consequence of muscular spasm caused by pain, rather than mechanical obstruction of the articular disc [5, 10, 12, 13, 14, 15, 16, 17].
Sensitivity of the joint to palpation in patients with single or reciprocal click, even in the absence of pain, indicates that there was no adaptation of the joint tissue to this condition. The patient should be aware that the dysfunction has a progressive course and that painful sensations may also occur, especially when it comes to patient with parafunctions [16, 17, 18].
If the disc displacement with reduction is accompanied by pain, all management measures should be taken to alleviate or eliminate pain and second to improve function.
The benefit of the use of some intraoral devices in the management of patients with disc displacement with reduction is still subject of discussion. Most commonly applied intraoral devices are repositioning splint and stabilization splint [18, 19, 20, 21, 22, 23]. Recently in the literature, the modified mandibular splint has been mentioned, which achieves significant success rate in eliminating joint sounds and patients had no complications because of occlusal changes .
The basic aim of the repositioning therapy is to temporarily stabilize the mandible in an appropriate anterior position that allows the disc, if possible, to take a normal position on the condyle, and that the retrodiscal tissue releases the pressure and thus eliminates the pain and clicking sounds of the joint. Much more important is moving the condyle forward, which should enable the adaptive and regenerative processes in the retrodiscal tissue. Why this adaptation occurs in some patients, and in others not, it is not yet clarified. The goal of repositioning therapy is, therefore, to eliminate pain and allow relaxation and regeneration, actually transformation of the retrodiscal tissue [10, 18, 19, 20, 22, 23] (Figures 4–6).
Repositioning therapy may, however, also have some consequences. Therefore, repositioning therapy can be considered as a temporary treatment that reduces pain and joint sounds in a relatively short period of time. The results of long-term use of the repositioned splint are, however, not encouraging, especially in terms of eliminating the sound signals. In spite of these shortcomings, repositioning therapy has its place within the noninvasive (conservative) methods of treating patients with anterior disc displacement with reduction [18, 19, 20, 22, 23].
Some authors recommend that treatment begins by introducing a stabilization splint during a certain time because adverse long-term effects are minimized. A stabilization splint is applied in the upper jaw at night and, preferably, 1–2 hours during the day for several weeks (Figures 7 and 8). If there is no symptom reduction during stabilization splinting therapy, repositioning therapy should be continued. Before performing a repositioning splint, it is good to perform a test that will show whether the mandibular repositioning eliminates the sounds and the amount of propulsion required. This is done by maximizing the mouth opening in order to reduce the disc to a normal position. At the upper dental arch, place several layers of wax for the shaping, then the mandible is easily brought to the protrusion position, about 2–3 mm in front of the maximal intercuspal position. If the sounds are heard when reaching the mandible in that position, it is unlikely that the repositioning therapy will be successful in correcting the condyle-disc relationship. Clicking in the early (initial) mouth opening phase has a better prognosis than clicking at later stages. It indicates a minor disorder, a smaller amount of disc displacement, and less damage to the discal ligaments.
After 2–3 months of application the repositioning splint worn 24 hours a day including when the patient is eating (if possible), if the pain is significantly reduced or eliminated, the anterior repositioning splint should be reconverted to the stabilization splint. Treatment is considered successful if the patient does not have any pain, regardless of whether the joint sounds are present. If pain occurs again, the treatment with anterior reposition of mandible should be repeated. However, before recreating the repositioning splint, it is necessary to check whether there are additional factors that jeopardize treatment (bruxism, harmful habits) and whether the patient wears a splint as instructed by the physician. Certainly, the patient should be warned of the need for maximum control of parafunctional activities, eliminating bad habits, avoiding strong and long-lasting chewing, hard food, etc. [12, 20, 22, 23].
Disc displacement with reduction sometimes requires immediate treatment, even though the patient does not complain on pain. In patients with intermittent joint blockades, treatment should begin immediately, as such conditions can lead to serious injuries to the joint, most often the disc displacement without reduction. All pain-related disc displacements require treatment.
3.1.2 Disc displacement without reduction
This condition is characterized by anterior or antero-medial disc displacement in closed mouth conditions, where the disc does not return to the normal condyle relationship during mouth opening or condyle translation. Translational movements of the condyle are limited or disabled as it cannot pass under the dislocated and deformed disc. Pressed disc changes its shape, from biconcave to biconvex, and the anterior disc connection is relaxed. The contact between the condyle, the disc, and the articular eminence is lost, the space which normally occupies the disc is reduced, and the deformed disc is below the condyle. This results in restricted translation of the condyle in the affected joint, limited opening of the mouth, and sometimes with complete blockade of the mouth opening (“closed lock”).
Due to more efficient approach to therapy and overall prognosis, the state of anterior disc displacement without reduction can be divided into two stages—acute and chronic.
18.104.22.168 Acute disc displacement without reduction
Since limited mouth opening can be the result of muscular spasm, differential diagnosis should determine the true cause of this occurrence. It is known that contraction of the mandibular elevator muscles may limit vertical movements of mandible but does not significantly affect the lateral and protrusive range of motion. On the contrary, the intracapsular cause of mandibular movement restraints, such as disc displacement without reduction, leads to obstruction of all translational motion of the condyle in the affected joint and thus to the limitation of mouth opening, propulsion and lateral movement to the opposite side. If the movements of the mandible are not limited by the presence of strong pain, the intracapsular cause of mandibular obstruction usually permits the opening of the mouth by a pure rotation range of 25 mm. In cases of spasms or painful contraction of the mandibular elevator muscles, mouth opening may, however, be limited to several millimeters [5, 12, 25, 26].
The manual rearrangement therapist performs it by pressing the thumb to the lower teeth or the lower alveolar ridge of the affected side pulling the lower jaw downwards and separating the condyle from the articular eminence, thus providing a space for restoring the disc. If the reposition succeeds, as it can be seen from the considerably increased range of mouth opening, propulsion, and movement on the contralateral side, immediate repositioning splint should be introduced to prevent disc re-displacement. This splint should be made in advance and now modified so as to stabilize the mandible in the propulsive position 2–3 mm in front of the maximal intercuspal position. The patient needs to carry a splint constantly during the day and night, even during the meal, for the first 2–4 days before beginning only night-time use for at least 10 days. Also, a diet with only soft food should be prescribed. The patient should report at least once a week to evaluate the condition and eventually adjust the splint. If the disc is in the optimal position after this period, the repositioning splint can be replaced by a stabilization splint. If the joint blockade is repeated in spite of applied therapy, it is necessary to reanalyze the degree of dysfunction (the amount of disc displacement, possibility of its restoration) in order to establish a definitive therapy plan. The frequency of temporary joint blockades or long period disc displacement without reduction significantly reduces the chance for successful treatment (reposition) due to irreversible changes in joint tissue. Single, sudden joint blockade accompanied by limited mouth opening and intense pain has a much better prognosis, especially if the blockade is a consequence of a sudden trauma that has affected a healthy joint. The patient should be advised to use soft food and to maximally reduce the range of mandibular movements. If the attempt of manual reposition of the disc displacement fails, other alternatives should be considered [5, 12, 25, 26, 27].
22.214.171.124 Chronic disc displacement without reduction
In patients with chronic disc displacement without reduction, the disc is deformed and its last attachment is non-functional, so returning it to normal position is impossible.
3.2 Joint hypermobility (subluxation)
This disorder was previously referred to as “subluxation”.
Usually both joints are included, but hypermobility may be unilateral if it is the result of the joint hypomobility of the opposite side.
When the hypermobility of TMJs is part of the general (systemic) hypermobility of all the joint structures, it can be considered benign and no intervention should be undertaken [28, 29]. However, the joint hypermobility can lead to more difficult conditions, such as recurrent mandibular dislocation.
3.3 Spontaneous dislocation
If manual repositioning fails in the attempt, it is recommended to trigger the vomiting reflex by touching the soft palate by mirror. This inhibits the activity of the elevators and increases the chances of its manual repositioning. If the dislocation of the condyle-disc complex often repeats (becoming a chronic phenomenon), it is best to train the patient how to bring the mandible back to normal position using exercises like joint hypermobility [2, 33, 34].
Surgical intervention can be undertaken if this condition is often repeated and accompanied by pain. It usually consists of eminectomy (reduction of peak articular eminence) or eminoplasty (a surgical increase in inclination of the articular eminence) to prevent subsequent dislocations [35, 36].
4. Inflammatory and degenerative diseases of the temporomandibular joint
4.1 Inflammatory diseases in TMJs
Depending on the tissue in which the process takes place, inflammation of the TMJ is referred to as capsulitis, synovitis and retrodiscitis.
4.1.1 Capsulitis and synovitis
Capsulitis (inflammation of the external fibrotic layer of the joint capsule) and synovitis (inflammation of the synovial membrane) have almost the same clinical picture and are considered to be a unique clinical entity.
In the case of acute persistent pain, injection of corticosteroids (methylprednisolone 5–20 mg with 0.5 ml local anesthetic using 23–27 gauge, 05–1 inch needle) into the joint or joint area can reduce the pain and the inflammation. It should be cautious with corticosteroids because of the potential for damage to joint tissue. It is not recommended to administer more than three injections at short intervals . Corticosteroids should not be given if acute purulent infection is present.
If the inflammation is a consequence of chronic, repeated microtrauma or it has been secondary due to disc displacement, specific therapy is used to remove the source of the microtrauma or to allow the replacement of the dislocated disc [11, 37, 38, 39]. The use of stabilization splint for several weeks during the night, in these cases, reduces bruxism, reduces pressure on the joint and eliminates muscular spasm. Reposition splint therapy can help in cases where the primary cause is anterior disc displacement. This therapy minimizes the trauma of the discal ligaments.
Condyle pressure on richly vascularized retrodiscal tissue with a lot of nerves located behind an articular disc can lead to inflammation and swelling with significant functional disturbances.
Degenerative diseases of the TMJ differ significantly from those that have been written since they primarily damage bony articular surfaces of condyle and fossa. Some classifications characterize these diseases commonly referred to as arthritides . The different types are: osteoarthritis, osteoarthrosis, polyarthritides.
Degenerative diseases of the joint systems may be of local character, then they only affect specific joint structures such as TMJ or may, however, be part of the general systemic disease of all joints in the body (polyarthritis).
4.2.1 Osteoarthritis of the TMJ
Osteoarthritis is one of the most common arthritides affecting the TMJ. Osteoarthritis usually develops gradually and is limited in character. Degenerative processes in the TMJ even without a certain therapy end in about 3 years. The pain is reduced and the joint function somewhat regenerates, the volume of mandibular movements increases, and the creptions become less expressive. However, structural changes in the bone components of the joint are definitive. This stabilized condition is sometimes referred to as osteoarthrosis after the inflammatory process retreated and when pain is no longer present [11, 37, 39, 40, 42, 43, 44, 45, 46].
Changes in TMJ in lateral phases of disease can be observed on radiographic images, especially on the articular surfaces of the condyle in the form of the flattened surface, the presence of osteophytes, the cystic formation in the subchondral bone and the reduction of the joint space [12, 44].
The patient needs to take soft, almost fluid food; to avoid any function during the painful stages of the disease. Antirheumatics, NSAID, naproxen (Naprosyn) 500 mg two times per day for minimum of 3 weeks  or combination anxiolytic agent diazepam (Valium) 2.5 mg four times per day for 1 week than 5 mg four times per day for 2 weeks to and NSAID Ibuprofen 600 mg four times per day for 3 weeks are prescribed to reduce the pain and inflammation of the joints. The use of muscle relaxants cyclobenzaprine (Flexeril) 10 mg every night or sedatives clonazepam (Klonopin) 0.25 mg every night, increased by 0.25 each week to a maximum of 1 mg per day in patients with muscular spasms is suggested. Corticosteroid injections (methylprednisolone 5–20 mg with 0.5 ml local anesthetic using 23–27 gauge, 05–1 inch needle) help in cases of intense pain [11, 12, 37, 39, 40, 44]. Since mechanical overload of the joint is the main cause of osteoarthritis, it is recommended to use a stabilizing splint during the night and, preferably, 1–2 hours during the day for 6–8 weeks . If the pain is unbearable, if it does not decrease after the above mentioned treatment, the possibility of surgery is considered.
4.2.2 Osteoarthrosis of the TMJ
Osteoarthrosis is a non-inflammatory degenerative process that changes the morphology of joint components and mainly affects the articular surfaces of the TMJ and the subchondral bone. When bony changes are active, the condition is called osteoarthritis. As remodeling occurs the condition can become stable, yet the bony morphology remains altered [12, 45, 46].
Systemic polyarthritis can also involve the TMJ. The clinical picture is similar to that of localized osteoarthritis of TMJ.
Therapy of TMJ disease in these cases is palliative. It is recommended to rest the joints, take antiflogistics, analgesics and sedatives to relieve pain. The most common recommended drugs are NSAID, naproxen (Naprosyn) 500 mg two times per day for minimum of 3 weeks  or combination anxiolytic agent diazepam (Valium) 2.5 mg four times per day for 1 week than 5 mg four times per day for 2 weeks to and NSAID Ibuprofen 600 mg four times per day minimum for 3 weeks. In some patients, treatment may be attempted by stabilization occlusal split during the night for several weeks, which significantly reduces muscle hyperactivity, which relieves pain. Although there is an obvious occlusion instability, the use of irreversible occlusal therapy should be considered well and, of course, do not undertake anything to relieve the underlying disease and eliminate the inflammation in TM joints. If occlusal therapy is necessary because of the occlusion stabilization, the position of the condyle in relation to the articular eminence should be well analyzed. In cases of extreme damage of the TM joints and complete occlusion disorders, orthognathic surgery is indicated [12, 45, 46, 47, 48].
5. Ankylosis of the TMJ
Ankylosis is defined as immobilization or concrescence of the joint structures, caused by degenerative diseases, hemarthrosis secondary to joint injuries or surgical interventions. Inability or restriction of movement in the TMJ may be caused by fibrosis or bone tissue, which is less frequent [49, 50].
5.1 Fibrosis ankylosis
Hyperplasia of the fibrous tissue in the joint can lead to the ankylosis of the condyle, disc or retrodiscal tissue for the posterior wall of the joint capsule, articular fossa or the articular eminence.
Fibrosis may also occupy the joint capsule (capsular fibrosis), forming the binder fibers of the fibrous tissue inside the capsule, and may also cause general capsular thickening. This condition is characterized by a painless limitation of the mandible movement on the opposite side.
5.2 Bone ankylosis
In a clinical finding, one-sided ankylosis is dominated by a poorer development of the affected side—the middle of the chin and the bite center are moved to that side. In the case of bilateral ankylosis, there is a so-called “ bird’s face” appearance. The lower jaw is generally undeveloped. Due to the inability to open the mouth, hygiene is usually poor, with a consequent set of teeth caries .
The signs and symptoms of disease and dysfunction of TMJ are different in various disease groups and depend on the duration of the disease and its chronicity and as well as on the individual sensitivity of the patient. Proper identification of symptoms and precise diagnosis are therefore essential for future treatment.
Conflict of interest declaration
I confirm that there is no conflict of interest.