Salivary Oxidant/Antioxidant Status in Chronic Temporomandibular Disorders Is Dependent on Source and Intensity of Pain – A Pilot Study

Abstract

Temporomandibular disorders (TMD) have been associated with altered salivary oxidative status, but the relation with pain source and pain severity isn’t clarified. With the aim to assess their interaction with TMD, we compared levels of selected salivary oxidative stress (OS) markers (glutathione peroxidase, superoxide dismutase, total antioxidant capacity (TAC), uric acid, 8-hydroxydeoxyguanosine, malondialdehyde) and salivary cortisol (SC) as a stress indicator, between 20 TMD patients and 15 healthy control subjects. In order to record differences relating to pain source and severity, patients were respectively classified according to specific diagnoses (myofascial pain or disc displacement (DD)), and pain intensity (high or low). TAC was significantly higher in TMD patients than in controls (morning p = 0.015; afternoon p = 0.005). Significant differences were also observed when TAC levels between high-intensity pain patients and controls were compared, as well as between DD patients and controls. In logistic regression analysis, higher levels of TAC were related to DD (morning OR: 1.66, 95%CI: 1.05–2.64, p = 0.029; afternoon OR: 2.10, 95%CI: 1.11–3.98, p = 0.021) and to high-intensity pain (morning OR: 1.81, 95%CI: 1.04–3.15, p = 0.037; afternoon OR: 1.79, 95%CI: 1.02–3.14, p = 0.043). We also found that morning SC was positively correlated with antioxidant parameters in TMD patients. Our data suggest compensatory mechanism as response to higher level of stress. This stress could be extrinsic and lead toward TMD, or intrinsic, emerging from established TMD, or could be both. The intensity and the source of pain should be considered important factors in future investigations evaluating salivary OS markers in TMD patients.

Effect of occlusal splint on oxidative stress markers and psychological aspects of chronic temporomandibular pain: a randomized controlled trial

“…Within-group analyses showed a significant decrease in TAC and UA in the SS group. Our previous study on OS indicators in chronic TMD 40 showed that TAC was significantly higher in TMD patients than in healthy controls. We suggested that higher TAC in patients with TMD pain lasting more than 6 months might imply a compensatory increase of the antioxidant enzymes in response to changing levels of OS as a prerequisite for efficient defense.…”

Changes in salivary oxidative status, salivary cortisol, and clinical symptoms in female patients with temporomandibular disorders during occlusal splint therapy: a 3-month follow up

“…The main reason for these differences may be that in our research, we chose only female patients with chronic pain lasting 6 months or more. This six-month period provided an opportunity for the patients to adjust to potentially high oxidant levels, resulting in higher TAC levels [18]. Similar opposing results, where researchers observed higher or lower levels of TAC, have been found in other pathologies as well (e.g., atherosclerosis) [32, 33].…”

“…When it comes to TAC levels in various diseases, data are inconsistent. Research addressing oxidative status in TMD patients is scarce [17, 18, 29–31], and to the best of our knowledge, no study has attempted to track changes in OS biomarker levels during TMD therapy. Rodriguez de Sotillo et al and De Almeida and Amenábar found that TAC levels were lower in the TMD group than in control groups, indicating reduced antioxidant protection [17, 31].…”

“…Studies have found significant differences in the expression of OS biomarkers and antioxidants between TMD patients and healthy individuals [17, 18]. Therefore, the estimation of OS biomarkers can be used as an additional tool for early detection, diagnosis, and monitoring of TMD patients.…”

“…An association between higher levels of OS markers with higher pain intensity scores has been reported [17]. Our previous study addressed the differences in oxidative status by considering pain intensity and the specific diagnostic subgroups of TMD [18]. Hence, the applied therapy might depend on the clinical subtype of TMD and can have a different effect on different individuals depending on whether they report high-intensity pain (HIP) or low-intensity pain (LIP).…”