Craniomandibuläre Dysfunktionen und MRT-Befunde der Kiefergelenke bei Militärluftfahrzeugführern

Background and aims Temporomandibular dysfunction (TMD) of the temporomandibular joint (TJ) shows a multiplex symptomatology. TMD can restrict military pilots (MP) in flight operations and thus endanger the fulfillment of military missions. The aim of this study was to analyze the occurrence of TMD in MP of the German Armed Forces. In detail, it should be investigated whether TMD prevalence is associated with the aircraft type, which comorbidities are associated with TMD, and whether TMD compromises the military fitness to flying (MFF) of the MP. Material and methods The present cross-sectional study included 1,409 male MP (46% helicopter pilots (HP), 21% propeller pilots (PP) and 33% jet pilots (JP)) having been evaluated between September 2018 and March 2020. In addition, magnetic resonance imaging (MRI) with 48 TJ of 24 MP with TMD and a case-control study with 182 MP were carried out for the first time. Collected data were evaluated retrospectively. TMD prevalence and abnormal MRI findings of the TJ were determined and MP with and without TMD were compared with regard to flight altitude, aircraft model, orthodontic treatment for bruxism, hard tooth tissue and periodontal defects, dentures, comorbidities, and judgment of MFF. The statistical analyzes (Mann-Whitney U test, Fisher test, biserial correlation, McNemar test, Wilcoxon signed rank test and Cochran Q test) were performed with a significance level of α=0.05. In addition, binary logistic regression and mediation analyzes were performed using control variables. Results The overall prevalence of TMD (N=1,409) was 6.5% (91 cases, mean age 40.5 ± 9.8 years; mean flight hours 2598.7 h). TMD prevalences in the aircraft type subgroups were 6.4% for HP, 8.7% for PP and 5.1% for SP. TMD occurred more frequently in PP in the aircraft model “P-3C Orion” (odds ratio (OR)=5.40; 95% confidence interval (CI): 2.14–13.64) and in HP in the “Sea Lynx MK88A”. There was a significant correlation between abrasions and TMD for all MP; with the largest OR for SP. In contrast, PP with TMD showed more frequent erosions (OR=4.00; p=.040). In HP, tooth wear for bruxism, headache syndromes, and – detected for the first time – white matter lesions (OR=1.75; p=.026) were significantly associated with TMD. Furthermore, in SP there was a significant association between TMD and tinnitus (OR>9.00; p=.004) and a striking association between TMD and posterior condyle dislocation with tinnitus (OR=11.0; CI: 2.40–50.49). After 1,000 hours of flight, MP with TMD had a 3.6-fold increased risk of unilateral TJ-osteoarthritis compared to MP with little or no flight experience. Furthermore, MP with TMD were excluded from MFF 6.2 times more often than MP without TMD, with the comorbidities associated with TMD not acting as a mediator. In contrast, MP with and without TMD did not differ with regard to the parameters flight altitude, recession and dentures. Conclusion Within the limitations of the present study, results suggest that flight physiologic stress in combination with TMD leads to numerous and sometimes severe symptoms in MP that significantly increase the risk of incapacity to fly with increasing number of flight hours. Knowledge of TMD and its comorbidities should therefore become part of flight medical training. To secure MFF, controls of TJ should also be included in the standard procedure of the initial and follow-up MRI examinations of MP in order to be able to diagnose and treat pathological changes in good time. The integration of the examination of the TJ into the MRI standard procedure is a medically necessary, organizationally and economically sensible measure that can contribute to ensuring the strategic fulfillment of the Bundeswehr’s tasks. A possible causal relationship between high-vibration aircraft models and TMD should be clarified in follow-up studies. The same applies to potential induction of dislocation of the disc-condyle complex and subsequent provocation of tinnitus by acceleration forces. Furthermore, further studies should be carried out on the association between white matter lesions and TMD, which has been demonstrated for the first time. In affected MP, controlled exposure of MFF should also be considered to protect against severe clinical manifestations.