The frequency of selected polymorphisms, one in each gene coding for proteins with antioxidative properties (CAT(rs1001179), SOD2(rs4880), GPX1(rs1050450), and NQO1(rs689452)), was compared between patients suffering from pain-related temporomandibular disorders (TMDp; n = 85) and control subjects (CTR; n = 85). The same was evaluated when participants were divided with respect to oral behavioural habits frequency into high-frequency parafunction (HFP; n = 98) and low-frequency parafunction (LFP; n = 72) groups. Another aim was to investigate whether polymorphisms in these genes can be associated with participants’ psychological and psychosomatic characteristics. Polymorphisms were genotyped using the genomic DNA extracted from buccal mucosa swabs and real-time TaqMan genotyping assays. No differences in genotype distribution between TMDp patients and control subjects were found. Still, TMDp patients who were homozygous for minor allele A, related to the GPX1 polymorphism rs1050450, reported significantly more waking-state oral behaviours than GA + GG genotype carriers (score: 30 vs. 23, p = 0.019). The frequency of genotype AA for rs1050450 polymorphism was higher in HFP than in LFP participants (14.3% vs. 4.2%, p = 0.030). The most important predictors of waking-state oral behaviours were depression, anxiety, AA genotype (rs1050450), and female sex. The explored gene polymorphisms were not found to be significant risk factors for either TMDp or sleep-related oral behaviours. The association of waking-state oral behaviours with selected gene polymorphisms additionally supports previous assumptions that daytime bruxism is more closely linked to various stress manifestations, which might also be reflected through the variability related to the cellular antioxidative activity.

This case-control study investigated single nucleotide polymorphism (SNP) genotypes (CXC motif chemokine ligand 8 (CXCL8): rs2227306 and rs2227307 and tumor necrosis factor (TNF): rs1800629) in 85 patients with pain-related temporomandibular disorders (TMDp) and 85 controls to explore their associations with TMDp presence, pain intensity (low/high), and the presence of chronic arthralgia/myalgia. TMDp was diagnosed using a validated protocol, and polymorphisms were genotyped from buccal mucosa swabs using TaqMan assays. High pain intensity individuals had an increased risk for carrying minor allele “G” (rs2227307) and “T” (rs2227306) compared to controls (76% vs. 55.3%, p = 0.012; 72% vs. 54.1%, p = 0.030, respectively). Carriers of the minor allele “G” (rs2227307) were more prevalent in TMDp patients with arthralgia compared to controls (70.30% vs. 55.30%, p = 0.037). According to logistic regression, the most important predictors for high pain intensity were minor allele “G” of rs2227307 (OR 2.435, 95% CI 1.123–5.282), increasing age (OR 1.038, 95% CI 1.002–1.075), and female sex (OR 4.592, 95% CI 1.289–16.361). The explored gene polymorphisms were not significant risk factors for TMDp presence. These findings highlight the importance of genetic variations, particularly rs2227307, in understanding the diverse clinical manifestations of temporomandibular disorders.

Background: This genetic association study investigated single nucleotide polymorphism (SNP) in interleukin-8 (CXCL8) and opiorphin (OPRPN) genes, as well as psychological characteristics and oral behaviours, between patients with pain-related temporomandibular disorders (TMDp) and healthy controls. The aim was to examine associations and predictive value of these factors for TMDp subtypes: arthralgia and myalgia. Methods: A total of 85 patients with TMDp (arthralgia and/or myalgia) and 85 pain-free controls were included. Diagnoses were established following the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). All participants completed standardised self-report questionnaires assessing anxiety, depression, and oral behaviours. Buccal swabs were collected for DNA extraction, and SNP genotyping was performed using real-time PCR. Statistical analyses were conducted using dominant and recessive genetic models. Logistic regression models were applied to assess risk factors for each TMDp subtype. Results: Participants homozygous for the minor allele (CC genotype) of rs1387964 in OPRPN were significantly more prevalent in both arthralgia and myalgia groups compared to controls. Age and female sex predicted TMDp-arthralgia. Predictors of TMDp-myalgia included the CC genotype of rs1387964, age, female sex, anxiety, and depression. Conclusions: Genetic background and psychological characteristics were significant predictors of TMDp myalgia, highlighting a multifactorial profile for this TMDp subtype.

The frequency of selected polymorphisms, one in each gene coding for proteins with antioxidative properties (CAT, SOD2, GPX1, NQO1) was compared between patients suffering from pain-related temporomandibular disorders (TMDp;n=85) and control subjects (CTR;n=85). According to the Oral Behaviours Checklist score participants were divided into high-frequency parafunction (HFP;n=98) and low-frequency parafunction (LFP;n=72) groups. In addition, we have investigated the association of selected polymorphisms with participants' psychological (anxiety, depression) and psychosomatic (hypervigilance, somatosensory amplification) characteristics. Polymorphisms rs1001179, rs4880, rs1050450, rs689452 were genotyped using the genomic DNA extracted from buccal mucosa swabs and real-time TaqMan genotyping assays. No differences in genotype distribution between TMDp patients and control subjects were found. Still, TMDp patients who were homozygous for minor allele A, related to the GPX1 polymorphism rs1050450 reported significantly more waking-state oral behaviours compared to GA+GG genotype carriers (score: 30 vs. 23, p=0.019). Frequency of genotype AA for rs1050450 polymorphism was higher in HFP compared to LFP participants (14.3% vs. 4.2%, p =0.030). Most important predictors of waking-state oral behaviours were depression, anxiety, AA genotype (rs1050450) and female sex. Explored genetic factors were not found to be significant risk factors for either TMDp or sleep-related oral behaviours. The association of waking-state oral behaviours with selected gene polymorphisms additionally supports previous assumptions that the daytime bruxism is more closely linked to various stress manifestations, which might also be reflected through the variability related to cellular antioxidative activity.

Objective: This cross-sectional study investigated whether the frequency of waking-state and sleep-related bruxism is associated with sensitivity to occlusal tactile stimuli (i.e., occlusal tactile acuity) in healthy individuals. Methods: Forty healthy participants (20 females and 20 males) completed the Oral Behavioural Checklist to assess the frequency of waking-state and sleep-related bruxism. Participants were stratified into groups representing low, medium, and high bruxism frequency. Occlusal tactile acuity was evaluated using articulating foils of different thicknesses (8–56 μm) and sham trials presented in random order. Each stimulus was tested six times. Participants indicated whether they perceived a foil between their teeth. Signal detection theory was applied to distinguish perceptual sensitivity from response strategy. Results: Detection accuracy increased with foil thickness. Individuals with a high frequency of sleep-related bruxism exhibited reduced detection of thinner foils (8–24 μm) compared with those with low frequency of sleep-related bruxism (p = 0.029). Additionally, participants with high-frequency waking-state or sleep-related bruxism were more reluctant to report occlusal contact, indicating a more conservative reporting strategy (p = 0.045 and p = 0.002, respectively). Conclusions: Higher frequency of sleep-related bruxism was associated with reduced detection of low-intensity occlusal stimuli and a more conservative reporting strategy. These findings indicate an association between sleep-related bruxism frequency and differences in occlusal tactile detection. However, as the bruxism assessment was based on self-reports, these findings should be interpreted with caution.