The Salivary Cortisol Changes And Its Correlation With Pain Catastrophizing Under Electrical Stimulation In Patients With TMD

Aim Temporomandibular disorders are very common and often take place fequently in dental department,its pathogenic mechanism is unknown,pain is one of the most important symptoms in TMD,it will influence the TMD patients through neurophysiology way and psychological aspects and increase the suspectibility.The sudy will supply for an important theoretic basis for prevention and treatment.Methods According to the two-axis diagnostic standard for TMD(RDC/TMD),11 TMD and 11 healthy subjects were evoked by electrical stimulation.Collect the samples before test,after 50 s and 100 s seperately.Salivary cortisol were analysed by ELISA kit.All the subjects filled the pain catastrophizing scale(PCS) before stimulation.Finally,the results were statistically analysed.Results1.There is no statistically difference between age and gender of two groups of subjects(P>0.05);2.The salivary cortisol in TMD was higher than the control group,and it also happened in three points;the salivary cortisol are different(P<0.05)as the stimulation went on; but only the pre-stimulation and100 s later have statistical significance(P<0.05); No interaction between time and group factor(P>0.05).3.The salivary cortisol showed a downward trend as stimulation happened,especially 100s(P<0.05).4.The PCS total scores and three indexes(rumination,magnification,helpless) in TMD were higher than the control group(P<0.05), The pain threshold in TMD were lower than the control group(P<0.05).5. The total scores of PCS including three indexes were positive correlated with salivary cortisol(P<0.05). The total scores of PCS including three indexes were negative correlated with pain threshold(P<0.05).Conclusion1. The salivary cortisol in TMD was higher than the control group, it suggests that TMD patients are under more stress,and it breaks the balance between the neuroendocrine system and immune system and causes related diseases.2.Unpredictable stress cause high level of salivary cortisol in TMD, and with the occurrence of electrical stimulation, the body is adapted to the stress by studying, the cortisol decreases, the waiting period has more higher stress.3. TMD patients have high pain catastrophizing,and the total scores of PCS including three indexes were positive correlated with salivary cortisol. The potential pathway of pain catastrophizing may be caused by stress and increase the sensitivity of the pain.4. The pain threshold in TMD were lower than the control group, and the total scores of PCS including three indexes were negative correlated with pain threshold.The possible mechanism is that TMD patients has pain hyperalgesia under long time stimulation,it increases the negative cognization, but the specific mechanism needs further study.