Association Between Socio-Political Stress, Perceived Stress, and Clinical Signs of Bruxism Among Iranian University Students Studying in Turkey: A Cross-sectional Study

1. Introduction

Psychological stress is recognized as an important factor influencing both general health and oral health. University students are particularly vulnerable to stress due to academic demands, financial concerns, and social adaptation challenges. International students face extra stresses in addition to the difficulties faced by domestic students. Aside from their academic obligations, they frequently have to deal with being away from their families, acclimating to a new culture, and learning a foreign language. These pressures may be exacerbated by worries about social and political changes in their home countries. Prior studies have demonstrated that international students' mental health can be negatively impacted by geopolitical instability, economic uncertainty, and concerns about the security and welfare of family members [1,2].

The degree to which people consider the responsibilities of their everyday life to be overwhelming or challenging to handle is reflected in perceived stress. One of the most often used tools for evaluating psychological stress in behavioural and epidemiological research is the Perceived Stress Scale (PSS), which was developed by Cohen and associates [3]. Numerous psychological and physiological effects, such as anxiety, depression, sleep difficulties, and physical symptoms of stress, have been associated with higher perceived stress scores [4]. University students are typically thought to be more susceptible to high levels of perceived stress due to the demands of their studies and significant life changes.

Repetitive jaw-muscle activity, such as clenching or grinding teeth and/or bracing or thrusting the mandible, are symptoms of bruxism. According to a recent global consensus, bruxism is a behavior that can happen while you're awake or while you're sleeping, rather than a disorder in and of itself [5,6]. Psychological elements, particularly stress and anxiety, are thought to play a significant role in its multiple and complicated etiology [7,8]. Stress is positively correlated with bruxism-related symptoms in a variety of populations, including college students, according to several studies [9]. However, it is still unknown how strong and constant this link is in various cultural and demographic circumstances.

Iranian students form a large and important group among international students in Turkey. Last years, more young Iranians have studied abroad. This trend is connected to Iran's economic purpose and changeable periods of social and political instability. Turkey is a preferable choice for these population because it is close to Iran, has lower tuition costs, and offers easier admission and residental processes. On the otherhand, most Iranian students still have strong ties to their country. They stay connected through family, regular exposure to local news and social media, and ongoing financial or administrative responsibilities. So, even though students try to adjust to university life in Turkey, events in Iran can still affect their psychological well-being. Most earlier research has focused on international students from more politically stable countries. Because of this, few studies have examined the specific stress pattern that can occur when migration stress overlaps with ongoing socio-political concerns.

There is growing interest in the psychosocial causes of bruxism, but little is known about how socio-political stress may contribute to bruxism-related behaviors. Iranian students abroad may face specific stressors, such as economic sanctions, geopolitical tensions, and worry about family members at home. It is still unclear whether these extra stressors are linked to a higher rate of clinical bruxism. Therefore, this cross-sectional study aimed to examine the relationships between socio-political stress, perceived stress, and clinical bruxism findings among Iranian university students studying in Turkey.

2. Materials and Methods

This study aimed to evaluate the effect of socio-political stress on perceived stress levels and bruxism among Iranian university students studying in Turkey. The study also examined the relationship between stress arising from socio-political developments and students' psychological status and teeth clenching/grinding behaviors. The research was designed as a descriptive and analytical cross-sectional survey study.

2.1. Study Setting and Timeline

This research was conducted among Iranian university students studying in Turkey. Data collection was carried out primarily at the Faculty of Dentistry, using both face-to-face and online survey methods, with participants reached through randomized recruitment. Following ethics committee approval. Ethical approval was sought from the Non-Interventional Clinical Research Ethics Committee (2025-2026/03-26) and the study was carried out in accordance with the code of ethics in the Declaration of Helsinki. This was a cross sectional study conducted during the 2025-2026 academic year at the Faculty of Dentistry,

2.2. Study Population and Sample

The study population consisted of Iranian university students studying in Turkey. The sample was selected using a convenience sampling method, based on voluntary participation, among students who agreed to participate and met the eligibility criteria. Sample size was calculated using G*Power 3.1 software for analyses evaluating the relationship between socio-political stress, perceived stress, and bruxism. The power analysis was based on a 95% confidence level, 80% statistical power, and a medium effect size (effect size = 0.30). According to this calculation, the minimum required sample size was determined to be 85 participants. Considering possible missing data and incomplete questionnaire responses, the study aimed to reach at least 120–150 participants.

Inclusion criteria: Being an Iranian citizen; currently enrolled in undergraduate or graduate education at a university in Turkey; being 18 years of age or older; voluntarily agreeing to participate and providing consent; completing the questionnaire in full.

Exclusion criteria: Being under 18 years of age; not being an Iranian citizen; not being a university student in Turkey; incomplete or incorrectly completed questionnaires; refusal to participate or withdrawal from the study.

2.3. Data Collection Instruments

Data were collected through a questionnaire form prepared by the researchers. The first page of the form was designed to determine participants' sociodemographic characteristics, including age, gender, faculty and academic year, length of stay in Turkey, living arrangements, cohabitants, presence of first-degree relatives in Iran, and primary source of income. This section was used to describe participants' general characteristics and to assess sociodemographic variables potentially associated with stress levels.

The second page of the questionnaire was prepared by the researchers to assess the psychological effects of current socio-political developments in Iran on Iranian students studying in Turkey. The first scale consisted of 8 items assessing participants' socio-political stress levels experienced over the past month. Items were rated on a 5-point Likert scale (0 = Strongly disagree, 1 = Disagree, 2 = Undecided, 3 = Agree, 4 = Strongly agree). This scale assessed indicators of socio-political stress such as concern about family safety, financial uncertainty, anxiety about being unable to continue education, increased social media and news monitoring, and sleep and concentration problems. Higher scores indicated higher levels of stress related to socio-political developments.

The Perceived Stress Scale (PSS-10) was also included on the second page of the questionnaire to assess participants' general stress levels [10]. The scale was originally developed by Cohen, Kamarck, and Mermelstein (1983) to measure the degree to which individuals perceive events in their lives as stressful, evaluating stress experienced over the previous month. The Turkish validity and reliability study of the scale was conducted by Eskin, Harlak, Demirkıran, and Dereboy (2013) [10]. The scale consists of 10 items rated on a 5-point Likert scale (0 = Never, 1 = Almost never, 2 = Sometimes, 3 = Fairly often, 4 = Very often). Items 4, 5, 7, and 8 are reverse-scored prior to analysis. The scale has a unidimensional structure and measures an individual's perceived stress level. Total scores range from 0 to 40, with higher scores indicating higher perceived stress. In the Turkish adaptation study, the Cronbach's alpha reliability coefficient of the scale was reported as 0.82. The scale has been widely used in different age groups, particularly among university students and adults.

On the same page, participants were also directed to a brief assessment developed by the researchers to evaluate the presence of bruxism. This section included questions addressing symptoms of bruxism such as teeth clenching/grinding behavior, morning jaw fatigue, headache, tooth sensitivity, and noticeable tooth wear. Some items were rated on a 5-point Likert scale (0 = Never, 4 = Very often), while others were answered as yes/no. Behavioral factors potentially associated with bruxism, such as smoking and caffeine consumption, were also assessed. Data obtained from this section were used to determine the presence of possible bruxism symptoms and to examine their relationship with stress levels. On the third page of the questionnaire, clinically observable bruxism and joint findings were evaluated and recorded by the researchers.

2.4. Data Collection Procedure

Data were collected through both face-to-face and online survey methods. Participants were provided with written information about the study and voluntary informed consent was obtained. The survey link was distributed to Iranian university students studying in Turkey through social media and student communication groups. Participants completed the questionnaire independently and anonymously. The survey was designed so that participants could complete it only once, and responses were recorded anonymously. No direct or face-to-face intervention was performed during the data collection process.

2.5. Statistical Analysis

Statistical analyses were performed using Jamovi (version 2.7) and R (version 4.5). All variables were summarized descriptively as means, standard deviations, medians, minimum–maximum ranges, frequencies, and percentages, and the normality of continuous variables was checked with the Shapiro-Wilk test. Internal consistency of the socio-political stress module and the PSS-10 was evaluated using Cronbach's alpha calculated on the analytic sample (n = 113); item-rest correlations, alpha-if-item-deleted values, and the single-factor structure of the socio-political stress module were additionally examined using principal component analysis. The p-value of p < 0.05 was considered statistically significant.

3. Results

3.1. Participant Characteristics

A total of 113 Iranian university students studying in Turkey were included in the final analysis, with no missing data for age, duration of residence in Turkey, academic year, socio-political stress total score, PSS-10 total score, or clinical bruxism status. Participants' mean age was 24.1 ± 3.33 years (median 23, range 20–35), and they had lived in Turkey for a mean of 50.1 ± 19.0 months (median 49, range 25–132). The mean academic year was 3.29 ± 1.03, distributed as 16 fifth-year, 33 fourth-year, 32 third-year, and 32 second-year students.

Mean scores were 34.0 ± 7.44 (median 36, range 0–40) for socio-political stress and 25.6 ± 4.71 (median 24, range 12–37) for PSS-10. Clinical bruxism findings were present in 63 participants (55.8%) and absent in 50 (44.2%). The Shapiro–Wilk test indicated that age, duration of residence in Turkey, academic year, socio-political stress score, PSS-10 score, and clinical bruxism status all departed from a normal distribution, so non-parametric methods were used as the primary approach, supplemented by parametric analyses where these were appropriate. The participants' demographic and baseline characteristics are summarized in Table 1.

3.2. Reliability and Dimensional Structure of the Study Instruments

The sociopolitical stress subscale demonstrated strong internal consistency, with a Cronbach's alpha of 0.834. Corrected item-total correlations ranged from 0.47 to 0.74, indicating satisfactory discriminant capacity across all items; furthermore, no item's deletion would have increased the overall reliability coefficient, supporting the retention of the full item set.

The dimensional structure of the instrument was subsequently examined by means of principal component analysis (PCA). The first component, with an eigenvalue of 4.02, accounted for 50.3% of the total variance, and all eight items loaded positively (0.56-0.81), indicating a single dominant construct underlying the scale.

The Turkish PSS-10, by comparison, attained a Cronbach’s alpha of only 0.562 in this study-lower than earlier reliability estimates for the Turkish version (8) and short of 0.70 level typically assumed to signify good internal consistency. Consequently, findings derived from the PSS-10 should be interpreted with appropriate caution in the context of the present sample.

One reverse-scored item showed a near-zero item-rest correlation (r = 0.01), and removing it would have raised alpha only to 0.60. This lower-than-expected reliability of the PSS-10 in this specific population is reported transparently and is discussed further below. Internal consistency results are summarized in Table 2.

3.3. Inter-Examiner Reliability of Clinical Bruxism Findings

All 113 participants were independently examined by two trained, calibrated examiners blinded to each other's findings, to self-reported responses, and to study hypotheses (one item, joint sound, had a single missing value for the second examiner; n = 112 for that comparison). Inter-examiner agreement (Cohen's kappa, weighted for ordinal and unweighted for binary variables) was excellent to almost perfect overall (κ = 0.900–1.000). Granular BEWE tooth-wear scores showed excellent but not absolute agreement (κ = 0.958–0.991; 1–5 single-grade discrepancies per region of 113); muscle palpation scores ranged from κ = 0.938–0.994, and jaw pain/locking showed the lowest agreement observed (κ = 0.900; 4 discordant cases). For the composite clinical bruxism finding (primary outcome), agreement remained excellent (κ = 0.982, 99.1%; 1 discordant case). Full results are in Table 3.

3.4. Sociodemographic and Background Characteristics

Most participants reported having a first-degree relative in Iran (n = 100, 88.5%), while 13 (11.5%) did not. Among those with a first-degree relative in Iran, 46 (86.8%) reported difficulty communicating with them, while 7 (13.2%) did not. The most common source of income was family support (n = 99, 87.6%); 9 participants (8.0%) reported both family support and employment, and 5 (4.4%) relied on employment alone. Regarding living arrangements, 48 participants (42.5%) lived alone, 33 (29.2%) lived with friends, and 32 (28.3%) lived with family.

Tobacco use was reported by a minority of participants: 67 (59.3%) reported no use, 17 (15.0%) rare/social use, 21 (18.6%) 1–10 cigarettes/day, and 8 (7.1%) more than 10 cigarettes/day. Daily caffeine intake was absent in 7 (6.2%), low in 53 (46.9%), moderate in 38 (33.6%), and high in 15 (13.3%) participants. Following recent developments in Iran, 62 participants (54.9%) reported an increase in related habits, 30 (26.5%) reported a marked increase, and 21 (18.6%) reported no change.

3.5. Self-Reported and Clinical Bruxism-Related Findings

Self-reported bruxism-related symptoms were common. Daytime tooth clenching was reported at varying frequencies, with 83 participants (73.5%) reporting at least some degree of daytime clenching. Regarding sleep-related bruxism, 26 participants (23.0%) reported being told they clenched or ground their teeth during sleep, 41 (36.3%) reported no such history, and 46 (40.7%) did not know. Morning jaw fatigue or headache was reported by 75 participants (66.4%) at some level of frequency. Tooth sensitivity was reported by 41 participants (36.3%), and self-perceived tooth cracks or wear by 28 (24.8%).

Clinical tooth wear (BEWE ≥ 1) was present in 89 participants (78.8%), with anterior wear more common than posterior wear. At least one soft tissue or muscle-related finding (linea alba, cheek biting marks, tongue scalloping, or masseter hypertrophy) was present in 82 participants (72.6%). Muscle palpation tenderness of at least grade 1 was present in 72 participants (63.7%). Temporomandibular disorder-related findings — jaw pain/locking, deviation during mouth opening, or joint sounds — were present overall in 43 participants (38.1%). Combining these self-reported and clinical criteria, clinical bruxism findings were present in 63 participants overall (55.8%). Detailed frequencies are presented in Table 4.

3.6. Comparison of Stress Scores According to Clinical Bruxism Status

Socio-political stress and PSS-10 scores were compared between participants with and without clinical bruxism findings. Participants with clinical bruxism findings had a mean socio-political stress score of 33.7 ± 7.64 (median 37.0), compared with 34.3 ± 7.25 (median 36.0) among participants without clinical bruxism findings; this difference was not statistically significant (Student's t = -0.439, p = 0.661; Mann-Whitney U = 1542, p = 0.849). Similarly, PSS-10 scores did not differ significantly between participants with clinical bruxism findings (25.5 ± 4.96, median 25.0) and those without (25.7 ± 4.41, median 24.0) (Student's t = -0.312, p = 0.755; Mann-Whitney U = 1558, p = 0.921). These results indicate that neither socio-political stress nor perceived stress scores were significantly higher among participants with clinical bruxism findings compared with those without. Results are summarized in Table 5.

3.7. Correlation Between Socio-Political Stress and Perceived Stress

A statistically significant, moderate positive correlation was observed between socio-political stress total score and PSS-10 total score (Pearson's r = 0.397, p < 0.001), confirmed by Spearman correlation analysis (rho = 0.339, p < 0.001). These results indicate that higher socio-political stress was associated with higher perceived stress among Iranian university students studying in Turkey.

3.8. Logistic Regression Analysis

Binary logistic regression analysis was performed to examine whether PSS-10 score predicted clinical bruxism status (present versus absent), first unadjusted, then adjusted for age, and finally in a fully adjusted model additionally including smoking status and daily caffeine intake. In the unadjusted model, PSS-10 score was not significantly associated with clinical bruxism status (OR = 0.987, 95% CI 0.912–1.069, p = 0.753); the McFadden R² of this model was 0.0006, indicating that perceived stress alone explained a negligible proportion of the variance in clinical bruxism status.

In the age-adjusted model, PSS-10 score remained non-significant (OR = 0.990, 95% CI 0.910–1.077, p = 0.814), whereas age was significantly associated with clinical bruxism status (OR = 1.383, 95% CI 1.163–1.644, p < 0.001): each additional year of age was associated with approximately 38% higher odds of presenting a clinical bruxism finding. The McFadden R² of the age-adjusted model was 0.126.

In the fully adjusted model, which additionally included smoking status and daily caffeine intake, PSS-10 score remained a non-significant predictor (OR = 0.961, 95% CI 0.879–1.051, p = 0.388), and age remained significantly associated with clinical bruxism status (OR = 1.438, 95% CI 1.191–1.735, p < 0.001). Smoking status was not significantly associated with clinical bruxism status (OR = 1.057, 95% CI 0.686–1.628, p = 0.803). Daily caffeine intake, however, was significantly associated with clinical bruxism status (OR = 2.128, 95% CI 1.193–3.794, p = 0.011): each one-category increase in caffeine consumption (e.g., from low to moderate) was associated with more than a two-fold increase in the odds of a clinical bruxism finding. The McFadden R² of the fully adjusted model was 0.173, the highest among the three models, indicating that age and caffeine intake together explained more of the variance in clinical bruxism status than perceived stress alone. Results of all three models are summarized in Table 6.

4. Discussion

This study investigated the relationship between socio-political stress, perceived stress, and clinical bruxism findings among Iranian university students studying in Turkey. Contrary to our initial hypothesis, perceived stress (PSS-10 score) was not significantly associated with clinical bruxism status in any model, and neither socio-political stress nor perceived stress scores differed significantly between students with and without clinical bruxism findings.

In this study, we did not find a significant link between perceived stress and clinical signs of bruxism among Iranian university students studying in Turkey. This result is different from earlier studies, which found a positive link between perceived stress and bruxism symptoms in university students and young adults [9,11]. There are several possible reasons for this difference.

First, this was a pilot study with a very small and similar (homogeneous) sample. This may have made it harder to detect small correlations. The very low McFadden's R² of the uncorrected model (0.00064) supports this idea. It shows that perceived stress explained only a small part of the differences in clinical bruxism results in this sample. Also, bruxism was not measured with instruments such as polysomnography or electromyography. Instead, it was measured using a combination of self-reported symptoms and a standard clinical exam. Clinical signs, such as tooth wear and muscle-related findings, may not respond quickly to stress felt at one point in time, because these signs usually build up over a longer period. Bruxism is a complex condition. Because of this, other factors — such as anxiety, symptoms of depression, sleep quality, coping strategies, and occlusal (bite-related) features — may matter more than perceived stress alone [12]. The quality of the measurement tools themselves may have also played a role.

In this sample, the Turkish PSS-10 showed lower internal consistency (Cronbach's α = 0.562) than earlier reports had indicated [10]; notably, one reverse-scored item had an almost negligible corrected item–total correlation (r = 0.01), which suggests that participants may not have interpreted the reverse-worded items consistently. Because reduced reliability tends to weaken observed associations, this may partly explain why no statistically significant relationship emerged between perceived stress and clinical bruxism. The researcher-developed socio-political stress module, on the other hand, performed satisfactorily on both counts, with good internal consistency (Cronbach's α = 0.834) and a clear single-factor structure accounting for 50.3% of the total variance—making it less likely that measurement error explains the lack of association between socio-political stress and clinical bruxism.

Socio-political stress was not linked to clinical bruxism findings, yet it correlated moderately and positively with perceived stress (r = 0.397, p < 0.001). This is in line with earlier evidence that international students can carry a heavier psychological burden when political instability, economic uncertainty, or concern for family persists in their home countries [13]. Taken together, these findings support the construct validity of the socio-political stress module and show that country-specific stressors contribute significantly to overall psychological stress in this population, even if that stress is not reflected in the clinical indicators of bruxism studied here.

Age was one of the few variables that was independently linked to clinical bruxism findings: after correcting for relevant confounders, each additional year increased the probability of having clinical bruxism by 43.8% (OR = 1.438). Age is closely related to both academic year and the length of stay in Turkey. Because of this, the link with age may actually reflect the cumulative nature of symptoms such as tooth wear and muscle changes, rather than a direct effect of age itself. We cannot rule out cohort differences (differences between groups of people from different time periods). A longitudinal study is needed to find out if increasing age really causes clinical bruxism, or if it simply reflects longer exposure to parafunctional activity (habits like teeth grinding or clenching).

Daily caffeine use was also independently linked to a higher risk of clinical bruxism (OR = 2.128). However, smoking showed no significant association. Caffeine is known to stimulate the central nervous system. It may affect arousal and the activity of the chewing (masticatory) muscles. For this reason, a link between caffeine and bruxism is biologically plausible. However, because this study used a cross-sectional design, this association should not be seen as proof of a cause-and-effect relationship. Future longitudinal studies are needed to test whether caffeine use directly contributes to the start or the duration of bruxism.

Clinical findings related to bruxism were quite common in this group. This was especially true for tooth wear (78.8%) and abnormalities in soft tissue or masticatory muscles (72.6%). These frequencies were similar to those found in other studies of young adult populations [14,15].

However, it is impossible to determine if these results are unique to Iranian overseas students or rather represent the baseline prevalence of clinical bruxism characteristics commonly observed in young adults in the absence of a reference group. Future studies with appropriate comparison groups drawn from both domestic and other international student populations would help resolve this question.

Clinically, these findings suggest perceived stress alone should not be relied upon as a proxy for bruxism risk, and that broader psychosocial, behavioral, and duration-of-stay factors should be considered; the socio-political–perceived stress correlation nonetheless supports screening for home-country-related psychological burden in this population.

Limitations of the Study

This pilot study has several limitations. First, sampling of academic years was uneven and non-random: coverage ranged from 74–100% among second- to fifth-year students, and first-year students could not be reached and are absent from the sample. Because age correlated with academic year, this gap may have introduced selection bias affecting the age–bruxism association observed, and findings should be considered hypothesis-generating rather than confirmatory. Second, this was a small, single-center study without a non-Iranian comparison group; participants may also have under-reported distress related to politically sensitive items despite anonymity safeguards, which would bias socio-political stress scores toward underestimation. Third, although the socio-political stress module showed good post-hoc internal consistency (α = 0.834) and a single-factor structure, it has not undergone full psychometric validation (content validity, confirmatory factor analysis, test–retest reliability); the Turkish PSS-10 also showed lower-than-expected reliability in this sample (α = 0.562), which may have attenuated its association with bruxism. Fourth, clinical bruxism status relied on a composite of self-report and clinical screening rather than instrumental criteria (e.g., polysomnography), although inter-examiner agreement was excellent for the primary outcome (κ = 0.982) and ranged κ = 0.900–1.000 across variables. Fifth, the cross-sectional design precludes causal inference; smoking and caffeine intake were adjusted for, but gender, anxiety, depression, sleep quality, and coping style were not measured. Larger, representative, longitudinal studies with comparison groups and a fully validated stress instrument are needed to confirm these findings.

5. Conclusions

This study provides preliminary evidence that socio-political stress is closely related to perceived stress among Iranian university students studying in Turkey, highlighting the influence of home-country circumstances on the psychological well-being of international students. Even so, after adjusting for potential confounders, neither socio-political stress nor perceived stress was independently associated with clinical bruxism findings.

Instead, older age and higher daily caffeine intake emerged as the independent factors associated with greater odds of clinical bruxism findings. These results highlight the multifactorial nature of bruxism and suggest that its clinical manifestations may owe more to cumulative behavioral or biological factors than to perceived stress measured at a single point in time. The dissociation observed here between psychological stress and clinical bruxism further suggests that stress-related pathways may not be fully captured by a cross-sectional assessment of either perceived stress or clinical signs.

These results should be interpreted cautiously due to the exploratory methodology and small sample size. To better understand the complex relationships between socio-political stress, psychological distress, and clinical bruxism, future research will need several improvements. This includes larger and more diverse groups of international students, suitable comparison groups, longitudinal follow-up (studying the same people over time), and validated tools that measure psychological stress and bruxism in a multidimensional way. Such studies could assist identify people who might benefit from focused preventive and supportive interventions and expand our knowledge of the psychological factors that contribute to bruxism in populations of overseas students.