Investigation of neurodegenerative and inflammatory processes in sleep bruxism

Comparative evaluation of salivary melatonin levels in patients with bruxism: a case-control study

Aim: To examine whether there is any difference in the levels of salivary melatonin between bruxism and nonbruxism groups and to compare the stress and anxiety levels between the two groups.Materials & methods: Patients meeting the probable bruxism criteria according to the International Consensus on the Assessment of Bruxism Criteria were included in the bruxism group. The salivary melatonin concentrations of both groups were measured using an ELISA kit. To determine the relationship between stress and bruxism, the State-Trait Anxiety Inventory (STAI) test was used.Results: The bruxism group had a significantly lower night-time salivary melatonin level than the control group (p < 0.05). No significant difference was determined between the bruxism group and the control group in respect of the STAI-T scores (p > 0.05).Conclusion: The study findings revealed a strong relationship between a low melatonin level and bruxism.

Evaluation of retinal thickness measured by optical coherence tomography in patients with generalized anxiety disorder

PURPOSE

To compare the peripapillary retinal nerve fiber layer thickness, macular thickness, ganglion cell layer thickness, and inner plexiform layer thickness determined by Optic Coherence Tomography in the patient group diagnosed with a generalized anxiety disorder who did not receive any psychiatric medication with the healthy control group.

METHODS

Forty newly diagnosed, drug-free Generalized Anxiety Disorder patients and 43 healthy age- and gender-matched control subjects were included in the study. Macular thickness, ganglion cell layer thickness, inner plexiform layer thickness, and peripapillary retinal nerve fiber layer thickness were measured using optical coherence tomography. Structured Clinical Interviews and a State-Trait Anxiety Scale were applied to both groups.

RESULTS

Gender distributions (P = 0.965) and mean ages were similar between the groups (P = 0.340). Retinal nerve fiber layer thickness measurements were not significantly different between the groups. We observed statistically significant thinning in the inner superior, inner nasal, inner temporal, inner inferior, and outer inferior quadrants of the macula in the patient group compared to the control group (P = 0.046, P = 0.046, P = 0.020, P = 0.007, P = 0.014). We found thinning at the Ganglion cell layer in the inner inferior and outer temporal quadrants (Respectively P = 0.018, P = 0.049), inner plexiform layer in the inner nasal, inner temporal, and inner inferior quadrants (Respectively P = 0.046, P = 0.044, P = 0.011) compared to the control group.

CONCLUSIONS

This is the first study to reveal thinning in the macula, ganglion cell layer, and inner plexiform layer in newly diagnosed, drug-free Generalized Anxiety Disorder patients compared to the control group.

Nutrient insufficiencies and deficiencies involved in the pathogenesis of bruxism (Review)

Stress has been well-documented to have a significant role in the etiopathogenesis of bruxism. Activation of the hypothalamic-pituitary-adrenal axis (HPA) and subsequent release of corticosteroids lead to increased muscle activity. Neurological studies have demonstrated that chronic stress exposure induces neurodegeneration of important neuronal structures and destabilization of the mesocortical dopaminergic pathway. These disruptions impair the abilities to counteract the overactivity of the HPA axis and disinhibit involuntary muscle activity, while at the same time, there is activation of the amygdala. Recent evidence shows that overactivation of the amygdala under stressful stimuli causes rhythmic jaw muscle activity by over activating the mesencephalic and motor trigeminal nuclei. The present review aimed to discuss the negative effects of certain vitamin and mineral deficiencies, such as vitamin D, magnesium, and omega-3 fatty acids, on the central nervous system. It provides evidence on how such insufficiencies may increase stress sensitivity and neuromuscular excitability and thereby reduce the ability to effectively respond to the overactivation of the sympathetic nervous system, and also how stress can in turn lead to these insufficiencies. Finally, the positive effects of individualized supplementation are discussed in the context of diminishing anxiety and oxidative stress, neuroprotection and in the reversal of neurodegeneration, and also in alleviating/reducing neuromuscular symptoms.

Systematic Review on the Link between Sleep Bruxism and Systemic Chronic Inflammation

Sleep bruxism (SB) is a sleep-related behavior characterized as rhythmic (phasic) or non-rhythmic (tonic) masticatory muscle activity. SB is a common sleep behavior with a predominantly central origin. The aim of this systematic review was to evaluate the relationship between inflammatory status and SB according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020). The research was registered at PROSPERO (CRD42023395985). We performed a systematic literature analysis using five different databases. Furthermore, the backward snowballing technique was applied to identify additional papers. Initially, 28 papers were screened from the database search, and 162 papers were revealed in the backward snowballing process. Eventually, five articles were included. Data concerning the inflammatory status of patients experiencing SB were investigated and summarized. Due to the heterogeneity of the compared studies, only a qualitative comparison and narrative summary were performed. The results suggest that SB could be associated with systemic inflammation. In fact, this systematic review revealed that there are no papers conclusively showing that the inflammatory status in bruxers is comparable to non-bruxers. However, each of the examined studies utilized different methods of assessing systemic inflammation, which makes the results dubious.

Polysomnographic Evaluation of Sleep Bruxism Intensity and Sleep Architecture in Nonapneic Hypertensives: A Prospective, Observational Study

Sleep bruxism (SB) is a repetitive jaw muscle activity characterized by clenching or grinding of the teeth, which is classified under sleep-related movement disorders in the International Classification of Sleep Disorders—Third Edition. Because the potential common pathomechanism of SB and arterial hypertension is the activation of the sympathetic system as well as an increase in inflammatory factors, we aimed to examine the intensity of SB and the sleep architecture among patients with arterial hypertension. The study included a total of 91 Caucasian adult patients, among whom 31 had arterial hypertension diagnosed according to the current European Society of Cardiology/European Society of Hypertension (ESC/EHS) hypertension guidelines. The control group consisted of 61 normotensive patients. Patients with obstructive sleep apnea were excluded. A single full-night polysomnographic examination was conducted in the Sleep Laboratory, and then the results were analyzed based on the guidelines of the American Academy of Sleep Medicine. Bruxism episode index (BEI) was higher in the hypertensive group compared to normotensives. The groups also showed statistically significant differences in polysomnographic sleep indexes. Similar to BEI, arousal index, apnea–hypopnea index, and snoring were higher in hypertensives compared to normotensives. On the other hand, the mean and minimal oxygen saturation were lower in hypertensives compared to normotensives. A statistically significant positive correlation was observed between oxygen desaturation index and BEI in the hypertensive group, whereas this correlation was not statistically significant in the case of normotensives. In summary, nonapneic hypertensives had higher SB intensity, altered sleep architecture, decreased mean oxygen saturation, and increased snoring compared to normotensives. The results suggest that dental screening is necessary for patients with arterial hypertension, especially those presenting with the symptoms of SB.

Sharing the Same Perspective. Mental Disorders and Central Serous Chorioretinopathy: A Systematic Review of Evidence from 2010 to 2020

Background: The relevance of the association between mental disorders and other conditions might have been underestimated due to its complexity. Central Serous Chorioretinopathy (CSC) is an ophthalmological disorder associated with many psychiatric factors. The aim of this systematic review is to evaluate the association between mental disorders and CSC. Methods: Articles about studies performed on humans on CSC published in peer-reviewed journals from 1 January 2010 to 31 December 2020 were included in the review. Results: We selected 21 research papers. Nine studies measured stress and anxious depressive symptoms, which are associated with CSC onset and recurrences, emerging as a state marker of the disease. Four out of the five studies focused on sleep disorders suggested a reliable association with CSC. Four studies evaluated other various psychiatric factors. The role of psychopharmacological medication has still not been elucidated (three studies). Conclusion: Multiple pieces of evidence highlights that CSC might arise in the context of systemic disease. This notion, together with the increasing evidence supporting a link between psychiatric disorders and choroidal thickness, suggests that CSC and mental disorders may share some etiopathogenetic pathways. Further research is needed to better investigate possible common etiopathogenetic pathways, especially vascular, immunological and endocrinological systems.

Evaluation of the Oxidative Stress Level and Serum Prolidase Activity in Patients with Sleep Bruxism

Aims and Objective:

Sleep bruxism is a complicated disease, and its cause remains controversial. If the etiology of bruxism is resolved, the treatment can be adjusted to the prevailing aetiological factor. Thus, the aim of this study was to evaluate the oxidative stress level and serum prolidase activity in patients with sleep bruxism.

Materials and Methods:

Seventy healthy subjects and 51 patients with sleep bruxism were included in this study, and blood samples from all patients were collected. Serum samples were analyzed for total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and prolidase activity.

Results:

The prolidase, TOS, and OSI levels were significantly higher in patients with bruxism than in the healthy controls (p = 0.001, p = 0.001, p = 0.001, respectively). The TAS level was significantly lower in bruxism patients than in healthy controls (p = 0.003).

Conclusion:

The increased TOS, OSI, and prolidase levels and decreased TAS levels could be assumed to result in oxidative injury in patients with sleep bruxism. However, the study could not determine whether oxidative imbalance and increased serum prolidase levels could be a cause or a result of bruxism.

Central choroidal thickness in children and adolescents with anxiety disorders: enhanced depth imaging optical coherence tomography findings

AIM

To measure the central choroidal thickness (ChT) in children and adolescents with anxiety disorders.

METHODS

Totally 41 anxiety patients (8-16y) and 35 healthy controls (age-matched) were evaluated. Complete ophthalmic examination was performed. Inclusion criteria were best corrected visual acuity ≥20/20, normal intraocular pressure (IOP; 10-21 mm Hg), and no systemic or ocular diseases according to history. The diagnosis of psychiatric disorders was determined using Schedule for Affective Disorders and Schizophrenia for School Aged Children Present-Lifetime Version (K-SADS-PL). Enhanced depth imaging optical coherence tomography (EDI-OCT) was used to measure the central ChT.

RESULTS

The mean age was 12.18±3.24y in the patient group and 12.86±3.15y in the control group. Age and gender distribution of the two groups was similar. Central ChT mean value was 353.26±31.9 µm in anxiety patients while 318.75±60.9 µm in the control group. Mean central ChT was statistically significantly higher in the children and adolescents with anxiety disorders than healthy controls (P=0.002).

CONCLUSION

The children and adolescents with anxiety disorders have significantly thicker central ChT than controls. In the larger sample, longitudinal studies will contribute to the use of choroidal differences as a clinical marker for monitoring anxiety disorders.

Investigation of the effects of temporomandibular joint arthrocentesis on blood volume of the retinal structures

Objective

Arthrocentesis is a minimally invasive surgical procedure that is used to alleviate the symptoms of temporomandibular joint (TMJ) disorders. The aim of this study was to investigate the effect of arthrocentesis on the blood supply to the retinal structures.

Materials and Methods

Arthrocentesis was performed on 20 patients with TMJ disorders, and choroidal thickness (CT) in patients was measured to evaluate retinal blood circulation. The blood volume of the retinal structures was evaluated ipsilaterally before and after arthrocentesis, and these measurements were then compared with measurements obtained from the contralateral side.

Results

Before arthrocentesis, there were no differences in retinal blood volumes between the ipsilateral and contralateral sides (P = 0.96). When ipsilateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was found to have significantly decreased after arthrocentesis (P = 0.04). When contralateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was also found to have decreased after arthrocentesis, but not significantly (P = 0.19).

Conclusion

The solution of local anesthesia with epinephrine applied before the arthrocentesis procedure was found to reduce the blood volume of the retinal structures. To the best of our knowledge, this is the first study that has investigated the blood volume of the retinal structures following arthrocentesis.