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.

BACKGROUND: Differences in the expression of oxidative stress (OS) markers between female patients with temporomandibular disorders (TMD) and healthy individuals indicate that OS plays a role in the pathogenesis of TMD. Because chronic exposure to stress generates oxidative damage during continuous stimulation of the hypothalamic-pituitary-adrenal axis, we expected that higher levels of cortisol might be associated with higher oxidative damage. Our aim was to test the association between OS markers, stress perception, and salivary cortisol (SC) in chronic, female TMD patients. We tracked changes in OS markers and SC during occlusal splint therapy in order to evaluate the influence of treatment on oxidative status. We hypothesized that the effects of TMD therapy would differ among individuals depending on the source and intensity of pain. METHODS: Sixteen female patients were recruited, and 12 finished the study. Clinical assessment and saliva sampling were performed at the baseline and follow-up appointments. Repeated measures analysis of variance and Pearson's correlation were used for analyzing the data. RESULTS: After 3 months, a significant reduction in afternoon total antioxidant capacity (TAC) was observed (p < 0.05). A significant reduction in afternoon malondialdehyde (MDA) (p = 0.021) and a decrease in afternoon MDA to superoxide dismutase ratios (p = 0.017) were present in high-intensity pain patients. At baseline, higher levels of perceived stress were significantly associated with higher morning cortisol (ρ = 0.67). At the end of the therapy,  reduced  perceived stress was positively correlated with morning SC changes when considering all TMD patients, but the association between perceived stress with OS markers was present only in myofascial pain (MP) group. The effect of treatment on the self-perceived quality of life was more pronounced in female MP patients while the reduction of spontaneous pain was significantly greater in high-intensity pain patients. CONCLUSION: Our data indicate that occlusal splint therapy in female TMD patients contributes to increasing their capacity to remove free radicals. The question remains whether or not TAC decreases in this process as a result of avoiding unnecessary processes, once the increase in antioxidants effectively compensates for OS. The intensity and the source of pain should be considered important factors in future investigations evaluating salivary OS markers and their association with perceived stress and SC in TMD patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT03029494 . Registered on 2017-01-19.

Risk factors for bruxism among Croatian navy employees.

The aim of the study was to evaluate the relationship between bruxism, and sociodemographic parameters, symptoms of temporomandibular disorders (TMD), personality and war experience among Croatian navy employees. The sample included 1092 subjects, aged 20-60 years (mean age 37·06 ± 7·85). An individual's bruxism status was based on clinical oral examination and participants' report of bruxism. Subjects with bruxism index values ≥ 90th percentile were included in severe bruxism group (n = 111), and those with scores below 90th percentile were labelled as negligible bruxism group (n = 981). No differences were found in gender distribution between the two groups. The proportion of military personnel presenting with bruxism is double the proportion of administrative employees with bruxism. A total of 23·34% subjects in negligible bruxism group and 48·65% in severe bruxism group participated in the war. Subjects in severe bruxism group presented more TMD-related signs and symptoms than those in negligible bruxism group. Higher prevalence of neuroticism and psychoticism was found in severe bruxism group. According to logistic regression, the probability of severe bruxism was significantly associated with marital status [Odds ratio (OR) 6·859, 95% confidence interval (CI) 3·869-12·158 P < 0·001], neuroticism (OR 2·842, 95% CI 1·434-5·632 P = 0·003), psychoticism (OR 2·618, 95% CI 1·193-5·746 P = 0·016), military duty (OR 1·828, 95% CI 1·013-3·298 P = 0·045) and masticatory muscles tenderness (OR 9·372, 95% CI 4·923-17·841 P < 0·001). Smokers had a 2·72-fold (95% CI 1·706-4·335 P < 0·001) higher risk of bruxism than non-smokers. Subjects who participated in war were more represented in severe bruxism group. Further studies, including other potential risk factors, are required to clarify these relationships.

Jaw elevator silent periods in complete denture wearers and dentate individuals.

Functional meaning and underlying mechanisms of jaw elevator silent period (SP) have still not been completely understood. Since complete denture wearers (CDWs) have no periodontal receptors in their jaws, the aim was to examine SPs in CDWs and to compare it with dentate individuals (DIs). Thirty six DIs (skeletal/occlusal Class I) and 24 eugnath CDWs participated. EMG signals were registered using the EMGA-1 apparatus from the left and the right side anterior temporalis (ATM) and masseter muscles (MM). Ten registrations of an open-close-clench (OCC) cycle were obtained for each individual. DIs had the average latency between 12.5 and 12.9 ms and always one single short inhibitory pause (IP) with complete inhibition of motoneurons (20.1-21.1 ms). On the other hand, in CDWs various types of SPs emerged: single or single prolonged SPs, double SPs, SPs with three IPs, periods of depressed muscle activity following the first, or the second IP, SPs with relative inhibition of motoneurons or even in several registrations the SP was missing. Unless more than one IP emerged, complete duration of inhibitory pauses (CDIP) was measured. CDIP varied from 37.17 to 42.49 ms. Average latencies were from 16.22 to 16.76 ms. Based on the results of this study it is obvious that both, the duration and the latencies were significantly longer in CDWs than in DIs (p<0.05), which can be explained by different mechanisms responsible for the muscle reflex behaviour.

The influence of age and dental status on elevator and depressor muscle activity.

The objective of this study was to determine whether the muscle activity at various mandibular positions is affected by age and dental status. Thirty edentulous subjects (E), 20 young dentate individuals (G1) and 20 older dentate individuals (G2) participated in this study. Surface electromyographic (EMG) recordings were obtained from the anterior temporal (T), masseter (M) and depressor muscles (D). Muscle activity was recorded during maximal voluntary contraction (MVC), maximal opening (O(max)) and in six different mandibular positions. One way anova and the Bonferroni tests were used to determine the differences between groups. Significant differences between the three tested groups were found at MVC and O(max) for all examined muscles (P < 0.001). The differences in muscle activity in dentate subjects of different age were found in protrusion for depressor muscles (P < 0.05) and in lateral excursive positions for the working side temporal (P < 0.05) and non-working side masseter and depressor muscle (P < 0.05). There was a significant effect regarding the presence of natural teeth or complete dentures in protrusion and maximal protrusion for all muscles (P < 0.05) and in lateral excursive positions for non-working side temporal (P < 0.05) and working side masseter muscle (P < 0.05). Muscle activity at various mandibular positions depends greatly on the presence of the prosthetic appliance, as edentulous subjects had to use higher muscle activity levels (percentages of maximal EMG value) than age matched dentate subjects in order to perform same mandibular movement. Different elevator muscles were preferentially activated in the edentulous subjects when compared with dentate group in lateral excursive positions of the mandible. The pattern of relative muscle activity was not changed because of ageing.

The significance of salivary interleukin 6 and tumor necrosis factor alpha in patients with oral leukoplakia.

It is well known that cytokines play an important role in oral diseases. Furthermore, increased levels of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) have been reported in patients with cancer and premalignant lesions such as oral lichen planus and oral submucous fibrosis. The aim of this study was to assess salivary IL-6 and TNF-alpha levels in 30 patients with histopathologically confirmed leukoplakia (age range 24-78, mean 52.3 years) in comparison to 34 controls (age range 27-79, mean 52 years). Salivary IL-6 and TNF-alpha were determined by enzyme linked immunoadsorbent assay. Statistical analysis was performed by use of Mann-Whitney test for independent samples and values lower than 0.05 were considered as significant (p<0.05). Significantly higher levels of salivary IL-6 and TNF-alpha in patients with oral leukoplakia when compared to healthy controls were found. The levels of salivary IL-6 and TNF-alpha did not correlate with the size of leukoplakia (lesions) nor with its localization regarding high and low risk sites for malignant transformation. Levels of salivary IL-6 and TNF-alpha were not influenced by smoking habits. We can conclude that increased salivary IL-6 and TNF-alpha might play a certain role in oral leukoplakia.