Understanding Noises in the Temporomandibular Joint

Introduction:

The temporomandibular joint (TMJ) is one of the most complex joints in the body. It is made up of three articular elements: the mandibular condyle, the glenoid cavity and the temporal condyle and the interarticular disc (1, 2) .

At rest, the interarticular disc is located between the anterosuperior part of the condyle and the posterior area of ​​the articular eminence, with the posterior band of the disc located in a 12 o’clock position (3) . 

When there is any alteration in the function of any of the elements that are part of the complex system of the temporomandibular joint, a series of disorders are triggered that together are called “TMJ Dysfunction” or “Temporomandibular Disorders (TMD)” ( 4 ) . 

TMD respond to a series of conditions characterized by pain in the joint or its surrounding tissues, functional limitations of the jaw or joint noises, being conditions with an etiology that is not entirely clear but is generally considered multifactorial.  

Among the most common symptoms include jaw pain, limited or painful mouth opening, headache, neck pain, TMJ noises or inability to open the mouth (4) .

Noises in the TMJ indicate an abnormality that is generally an indication of alterations in the position of the articular disc and are called disc displacements (3) . TMJ noises have been classified into two main types: clicking and crepitation (3) . 

Clicking is a special crackling or chattering noise. Various studies show an incidence of between 14% and 44% of the populations studied. Crepitation is another type of joint sound that is described as a series of rubbing or scraping noises and is associated with osteoarthritis, disc perforation, rheumatoid arthritis, and synovial chondromatosis (3) .

Cellic et al revealed that 45% of the population they studied presented some type of temporomandibular (TM) dysfunction, of which 40% corresponded to the manifestation of clicks or clicking in the joints and only 1% presented crepitation (5 ). .

García et al reported that of all patients who reported joint noises, 50% reported joint pain, 27.7% reported headache, 22.2% reported jaw blockage, and 11.1% reported ear pain (6) .

Some authors mention that friction on the articular surfaces is involved in the development of disc displacements. Microtrauma and macrotrauma appear to be involved in increasing intra-articular friction (7) . 

Quinteromarmol et al, carried out a study with a sample of 130 patients in which they demonstrated that joint noises occur in 78% of patients suffering from temporomandibular disorders and that 80% of the total reported more than one noise simultaneously.

The study revealed a significant relationship regarding the presence or absence of a canine and incisal guide with the manifestation of TM disorders (8) .

Nagamatsu et al. carried out an investigation in a population of adolescents in Okayama, Japan, observing a 95% incidence of clicking in patients who manifested nocturnal bruxism. It was shown that more than nocturnal clenching, the habit of grinding the teeth during the day was the most common habit associated with this manifestation (9) .

Azak et al, in 2006, conducted a study in a Turkish population demonstrating an incidence of 27.3% of patients with noises in the TMJ (clicking) and a correlation of clicking with parafunctional habits (clenching) was observed, demonstrating that the 39.4% of patients with noise manifested this characteristic (10) .

Winocur et al., carried out a study in 2001, in a population of adolescents between 15 and 16 years old to relate parafunctional habits and temporomandibular disorders in which it was demonstrated that the manifestation of noises in the TMJ was the second most common symptom. with 12.1% (11) .

Material and methods

An observational, prospective cross-sectional and explanatory study was carried out. 

1,000 patients who attended the postgraduate Restorative Dentistry clinic of the Faculty of Dentistry of the Autonomous University of Yucatán, Mexico during the period from January 2011 to May 2012 were studied, including 488 patients with a range of ages between 15 and 85 years, who met the inclusion criteria, which were a manifestation of some type of joint noise.

The following exclusion criteria were considered:

1. Patients with systemic joint disorders.
2. Patients diagnosed with systemic conditions that could affect the stomatognathic system and the temporomandibular joint.
3. Patients with a history of trauma to the lower jaw or the temporomandibular joint area.
4. Patients who were currently receiving any therapy for temporomandibular disorders.
5. Patients in whom the clinical examination was not possible to complete the data collection instrument.

Methodology

For the clinical evaluation of joint sounds, the patient was seated comfortably in a dental chair in a semi-reclined position with the occlusal plane parallel to the floor and in a state of relaxation.

Clinical palpation of the TMJ was performed in search of joint sounds by gently placing the fingertips of both hands in the area corresponding to the TMJ, applying light pressure, and the patient was instructed to make gentle opening and closing movements. maximum mouth closure.

Through this palpation, the type of noise and the affected joint were identified, considering the “click” as a short-duration sound and the crepitation as a prolonged, serious sound similar to the rubbing of two rough surfaces.

Once the type of noise and its location (in one or both joints) were established, it was recorded in the data collection instrument.

Subsequently, palpation of the temporalis, masseter, internal pterygoid and external pterygoid muscles was performed according to the protocol of Dr. Peter Dawson to determine the presence of muscle pain and this was recorded as positive or negative on the data collection instrument. .

The intraoral examination was immediately carried out using a number 5 mouth mirror with adequate lighting and after drying the mouth with pressurized air in search of the location of wear facets. Pieces with loss of dental substance and in which these surfaces presented a smooth and shiny appearance and with a number equal to or greater than 5 surfaces with pathological facetization were considered positive.

The presence of occlusal interferences in mandibular excursions was determined by placing a cheek retractor for better visualization and the patient was instructed to perform movements of right laterality, left laterality and protrusion, identifying the location in each movement using articulating paper. of occlusal interferences and these were recorded in the data collection instrument.

The presence of parafunctional habits (bruxism) was established through affirmation or denial by the patient.

The patient was questioned to determine if he had undergone any previous orthodontic treatment by recording it on the data collection sheet.

The data collected were entered into a Microsoft Excel database, processed and analyzed using the statistical software SPSS for Windows.

Results

Of the 1000 patients examined, 48.8% (n=488) of patients had TMJ noises, 95% (n=464) had clicking sounds, and 5% (n=24) had crepitus.

73% (n=356) of the TMJ sounds occurred in a single joint, that is, they were unilateral in location.

Of the 488 patients, 48% (n=234) presented pain in one or more masticatory muscles, with no significant differences observed in the number of patients who presented pain in the masticatory muscles, P=0.469

Wear facets and eccentric occlusal interferences presented the highest frequency with values ​​of 75% (n=366) and 86% (n=420) respectively.

In the variable, facets of wear, we have that for the 95% CI, there were significant differences, P=0.000

With respect to the variable, eccentric occlusal interferences, for the 95% CI, there are significant differences, P=0.000

Parafunctional habits were reported in 48.4% (n=236) of the total number of patients with noise (n=488), of which the most common type of habit was “clenching” or “grinding” during the day with a frequency of 30.5% (n=148), followed by the manifestation of “nocturnal grinding and bruxism” with 11.5% (n=57) and only 6.4% (n=31) presented “nocturnal bruxism”.

Regarding previous orthodontic therapy, no data was found since of the total number of patients, 6% (n=29) reported having previously undergone this type of treatment.

From this it can be explained that of all the variables studied there were statistically significant differences between the presence of eccentric occlusal interferences (85%) and the wear facets (74.6%) in comparison with the other study variables.

Discussion

At the end of the study, some similarities were observed that support what is described in the current literature regarding noises in TMJ.

The results coincide with the findings of Cellic R, Jerolimov V, Panduric J (5) , where a higher incidence of clicking is demonstrated compared to crepitation (45% clicking, 1% crepitation). In the present study, an incidence of 95% for clicking and 5% for crepitation was observed.

However, data contrary to what was described by Bisi, Batista and Puricelli (12) were observed , who mention that the majority of joint sounds manifest bilaterally with 74%, not agreeing with our results since a greater unilateral type involvement (73%).

With respect to parafunctional habits and muscular hyperactivity, the data show that just under half of the patients manifested it and that it also agrees with the data of Nakagatsu et al, (9) who observed a 95% incidence of clicking in patients who manifest nocturnal bruxism. 

However, the study showed that daytime teeth grinding was the most common habit rather than nighttime clenching. It should be noted that the presence of muscular hyperactivity and parafunctional habits were a constant (48%) in the present study.

On the other hand, what was described in the literature regarding orthodontic therapy and TM disorders was evident, as mentioned by Rakther et al. (13) in whose study no significant data were observed that demonstrate a direct association between orthodontic therapy and TMs disorders.  

In our study, only 5% of the participants had received prior orthodontic therapy, similar to what the aforementioned authors report.

At the end of the study, the presence of occlusal interferences (85%) and pathological facets (74.6%) was observed, reaffirming what was described regarding the occlusal factor as an important point for the performance of correct masticatory function and whose imbalance can affect the biomechanics of the system. stomatognathic triggering the deterioration of other elements that are part of this complex system.

Conclusions

From the data obtained in the study it is evident that TMJ involvement is frequent and that there is evident data of a correlation with the occlusal factor.

As dentists we can have a direct intervention on the occlusion and it is our duty to keep it in balance.

This study is not considered sufficient to affirm that the occlusion factor is an isolated determinant for the development of noises in the joint or temporomandibular disorders since, as described, there are many factors that trigger this type of conditions.

It could be mentioned that all the elements determining occlusion presented some degree of involvement (atm, muscles and teeth) but the dental factor presented a greater weight and greater frequency in the final results.

From this it is concluded that when carrying out the assessment and therapy of our patients it is important to take into consideration the occlusion and the absence of interference during the performance of eccentric mandibular movements since in the long run they generate harmful forces, levers and deflective muscle reflexes that will end with a deterioration of the articular system and the stomatognathic system in its entirety, affecting masticatory effectiveness and psychosocial performance, limiting the quality of life of our patients.