Temporomandibular joint (TMJ) dysfunction in rheumatoid arthritis (RA) occurs in 2 % to 86 % of RA patients. Dental factors possibly contributing to the development of TMJ dysfunction in RA patients have rarely been investigated in controlled studies. The present clinical study aimed 1) to compare patients with active, longstanding RA and healthy control subjects matched for age, sex, periodontal risk factors, dental and prosthetic status in order to obtain data on the prevalence of TMJ dysfunction in dentate RA patients and 2) to investigate a possible relationship between RA activity, general functional state and the severity of TMJ involvement.
50 RA patients (38 F, 12 M; 54 +/- 9 years) were compared with 101 control subjects (76 F, 25 M; 54 +/- 11 years) with regard to dental, periodontal and prosthetic status and clinical TMJ findings as measured by the Helkimo indices. Clinical evaluation of RA patients included serological parameters, pain as measured by visual analog scale (VAS), a 28-joint count, a radiological destruction score, a functional status and measurement of grip strength.
The sum of carious, missing and filled teeth was similar in both groups. RA patients had more missing teeth (p < 0.01), more gingival bleeding, deeper pockets and more attachment loss (p < 0.0001). They showed no differences with regard to the mean number of occluding pairs of teeth, tooth support, the percentage of dentures, the grade of prosthetic support. 36 % of RA patients had a unilaterally shortened dental arch compared with 11.9 % in controls (p < 0.05). 32 % of RA patients and 27.7 % of the control subjects reported TMJ or facial pain. The mean VAS was 50 +/- 19 for RA patients and 52 +/- 21 for controls. The anamnestic data and the clinical symptoms grouped according to the Helkimo index showed no significant differences between both subject groups. However, the maximal mouth opening capacity in RA patients was significantly lower (40.6 +/- 6.5 mm) than in controls (45.8 +/- 5.5 mm; p < 0.001). Analysis of the Helkimo symptom groups revealed a significantly reduced mobility index in the RA group and impaired TM-joint function in controls (p < 0.05). Grip strength was significantly correlated with mouth opening capacity, TMJ pain with tooth support.
The prevalence of TMJ dysfunction in dentate patients with longstanding RA does not exceed that of healthy controls when structural risk factors predisposing to the development of temporomandibular dysfunction are taken into consideration. Maintaining adequate tooth support might help to prevent progressive TMJ impairment in the course of disease.