Background: The polymyositis (PM) and dermatomyositis (DM) complex encompasses a heterogeneous group of acquired autoimmune skeletal muscle diseases called idiopathic inflammatory myopathies (IIM). Despite their histological and immunopathological differences, the end result of the affected muscles in all of these entities is the triad of chronic inflammation, fibrosis and the loss of muscle fibres. The aim of this study was to perform a complete analysis of the orofacial abnormalities in 34 patients with PM and DM.
Methods: Evaluation of subjective oral symptoms, measurement of whole resting saliva flow rate (WS) with the 'spitting method', a visual investigation of the oral soft tissue alterations, light- and electron microscopic analysis of the symptoms of capillary abnormalities or signs of focal infiltration in labial biopsy specimens were carried out. The number of decayed, missing and filled teeth (DMF-T) according to the WHO recommendations (1997), the periodontal probing depth (PPD), the plaque index (PI; Silness-Löe) and the gingival index (GI; Löe-Silness) were determined. For comparison with healthy controls the masticatory force (MF) and the force of the upper extremities' flexors were measured with a specially developed device. The SPSS version 11.0 for Windows software program, two-tailed Student's t-test and Mann-Whitney test were used to statistically analyse all data. Values were considered to be significant if P level was < or = 0.05.
Results: Nine patients complained of subjective xerostomia, 11 showed the signs of salivary hypofunction (WS < or = 0.1 ml/min). The most prominent symptom of the oral mucosa and perioral tissues was the presence of telangiectasia, detected in seven cases. Fibrosis of the minor salivary glands was found in 12 patients, interstitial-perivascular infiltration was detected in eight cases, periductal infiltration in one case. The findings on dental and periodontal conditions indicate, that the patients with IIM diseases had significantly higher DMF-T scores (24.06 +/- 7.04 vs. 19.54 +/- 8.93, respectively; P = 0.002), they had less remaining teeth in average (15 vs. 20; P = 0.002), compared with the control group. Their oral hygiene was significantly worse (PI was 1.46 +/- 0.75 and 0.73 +/- 0.54, P = 0.001). GI was significantly higher in the patients (1.27 +/- 0.60 and 0.66 +/- 0.56, respectively, P = 0.0003), although we could not demonstrate any difference in the severity of the periodontal destruction between patients and controls. Masticatory force was significantly weaker in the first molar region on both sides in the patient group (309 +/- 213 N and 113 +/- 146 N, P = 0.0016 for the right side; 315 +/- 239 N and 123 +/- 76 N, P = 0.009 for the left side), but only the left hands showed to be weaker in the patient group (77 +/- 27 N and 59 +/- 20 N, P = 0.04).
Conclusion: In conclusion, the present study showed that, patients with IIM diseases have hyposalivation and mucosal alterations, mainly in the form of telangiectasia. They have increased prevalence of dental caries, which may be secondary to the hyposalivation. The masticatory and the upper extremity flexor forces indicate that the weakness of the masticatory muscles can manifest earlier than that of the arms.