The evaluation of temporomandibular articulation during standard dental check-ups could help prevent effects related to biting and chewing, says study

Patients with rheumatoid arthritis require careful oral evaluation
2013-06-19

The evaluation of temporomandibular articulation during standard dental check-ups could help prevent effects related to biting and chewing, says study.

Patients with rheumatoid arthritis require careful oral evaluation

The evaluation of temporomandibular articulation during standard dental check-ups could help prevent effects related to biting and chewing, says study.

2013-06-19

The evaluation of temporomandibular articulation during standard dental check-ups could help prevent effects related to biting and chewing, says study

 

By Noêmia Lopes

Agência FAPESP – One the most common joints attacked by rheumatoid arthritis is the temporomandibular joint (TMJ), which is used to open one’s mouth and to chew. Despite this, studies evaluating the impacts of this disease on the orofacial region, which encompasses the face and mouth, where TMJ is located, are scarce. A group of researchers from the Universidade Federal de São Paulo’s Medical School (EPM/Unifesp) studied the biting force of patients with rheumatoid arthritis who were served by the institution and found that evaluation of the TMJ could help diagnose the disease before irreversible changes occur.

“We found that the orofacial region of these patients has more alterations than in the healthy population, including reduced biting force. The TMJ evaluation should, therefore, be a part of standard check-ups as a way of controlling inflammation and disease,” said Jamil Natour, Professor of Rheumatology at Unifesp and coordinator of the FAPESP-funded study on this topic.

Rheumatoid arthritis is an autoimmune disease caused by the immune system attacking the host – in this case, the synovial joints are the primary targets. The inside of this type of joint is covered by a synovial membrane, which rheumatoid arthritis causes to become thick and inflamed. The membrane then begins to produce substances that compromise the joint structures, causing damage to cartilage, bones, ligaments and tendons and resulting in deformities and other negative effects.

When evaluating the TMJ, the Unifesp researcher used two groups: the RA (rheumatoid arthritis) group, which included 75 Unifesp patients, and the control group, made up of 75 students without acute or chronic disease and without complaints in the TMJ area. These students were volunteers that came to the institution for routine exams, to donate blood or to accompany patients. “All participants were females who suffered from rheumatoid arthritis and were willing to be part of the scientific study,” explained Natour.

The comparison of the two groups involved an evaluation by dentist Carmen Paz Santibañez Hoyuela, a member of the research group who is completing her Master’s degree at Unifesp. Hoyuela obtained the medical history of each participant, conducted physical exams and had the subjects complete questionnaires on the performance of routine activities and on the development of rheumatoid arthritis, in addition to measuring the biting strength and hand strength.

This last factor was particularly important because it allowed the researchers to document whether losses in the two regions are simultaneous, which was demonstrated. “The damage to the hands is well known and well studied. We wanted to determine whether patients with rheumatoid arthritis and problems with their hands have problems with their TMJ,” explained Natour.

“We showed that a lower biting force accompanies a reduction in manual strength, showing that the orofacial region experiences attacks concomitant with those on other parts of the musculoskeletal apparatus and should, therefore, be monitored and evaluated,” he affirmed.

The measurements were made with dynamometers, devices used to determine strength. For the bite strength assessment, the researcher ordered a gnathodynamometer (to measure the force exerted when closing the jaws) that was developed and adapted for the study.

The instrument was used to measure the force of the molar teeth (on both sides) and incisors. To measure the hand strength and the pinching strength (between the thumb and index finger), the researchers used commercially available dynamometers that are internationally accepted as instruments to establish grip – the Jamar Dynamometer and Pinch Gauge, respectively.

“We correlated the results of the orofacial evaluation with the functional, clinical and activity parameters of the disease, as well as bite force and hand strength. That was how we concluded that women in the RA group had more signs and symptoms in the orofacial region and a lower biting force,” explained Natour.

Contributions and next steps

Rheumatoid arthritis affects 0.5% to 1% of the population and, in general, emerges between the ages of 30 and 40 – although it can appear at any age. The more intense and prolonged the joint inflammation, the greater the articular inflammation the disease can cause.

It is common for multiple joints to be compromised, and there is no definitive cure. Treatment involves medications, injections into inflamed joints, physical therapy and eventually surgery to limit the inflammatory process and the progression of lesions and to control pain and changes in the functions performed by the different regions of the body.

Whether the TMJ is compromised depends on factors such as age, the duration of the disease, the number of joints with edema, the presence of rheumatoid factor (the antibody found in approximately 90% of patients with rheumatoid arthritis), the C-reactive protein level and the erythrocyte sedimentation rate. However, Natour recalls, “These exams are nonspecific – any inflammatory disease even the flu, can change these parameters – and diagnosis is clinical.”

Now that it has been determined that the TMJ should be monitored to identify alterations caused by rheumatoid arthritis, the next step is to think about interventions that improve buccal and facial function and patient quality of life. It is now known that the first measure taken should be paying more careful attention to the oral check-up for anyone who has the disease.

Several other researchers participated in this study, including rheumatologist Rita Nely Vilar Furtado and a physical therapist and Master’s student, Aline Chiari, both of Unifesp. The study concluded in 2012, and the results were presented in the same year at the European Congress of Rheumatology in Berlin, Germany. A full article is currently under review for publication in a scientific journal.

 

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