Temporomandibular disorder pain is associated with increased sick leave and reduced health related quality of life.

BACKGROUND: Temporomandibular disorders (TMD) are the most common reason for chronic pain in the orofacial area and significantly impact the lives of those affected. The role of lifestyle factors in TMD, however, remains less explored. This cohort study aims to estimate TMD prevalence by addressing potential selection biases and to evaluate the association between TMD and lifestyle factors with a specific focus on sick leave and health related quality of life. METHODS: By linking data on TMD in the general population in Västerbotten, northern Sweden (n = 180,000) to health survey data (n = 120,000), information on sociodemographic factors and quality of life was available for 52,961 individuals (50.6% women) with a mean age of 53 years. We applied inverse probability weighting to adjust for selection bias and Poisson regression to explore associations with TMD. RESULTS: TMD prevalence was 9.2% during the study period, being higher in women (12.9%) than men (5.4%). Weighting for varying visiting frequencies did not affect TMD prevalence (average difference 0.4% points). Individuals with TMD, especially women, reported more sick leave and use of pain medication, with a significant association between TMD and increased sick leave (prevalence ratio 1.89, 95% CI: 1.78-2.01) among both women and men. In addition, TMD was associated with a lower health related quality of life (p < 0.001). CONCLUSION: The association of TMD with sick leave highlights the condition's profound impact on the lives of affected individuals. These findings underscore the influence of TMD on work life and the burden of TMD on the societal level. SIGNIFICANCE STATEMENT: The findings provide insight into how TMD affect individuals, by incorporating lifestyle factors, social determinants and the impact of sick leave at a population level. By incorporating these areas into the study of TMD, we can deepen our understanding of how TMD affects individuals' lives. This approach may also create opportunities to develop more comprehensive strategies to address TMD, focusing on broader implications beyond the clinical symptoms.

[Temporomandibular dysfunction and bruxism in patients with early rheumatoid arthritis and at-risk patients: a cross-sectional study]. / Temporomandibulaire disfunctie en bruxisme bij patiënten met vroege reumatoïde artritis en risicopatiënten: een cross-sectioneel onderzoek.

What is the prevalence of temporomandibular dysfunction in patients with early rheumatoid arthritis and individuals at risk of rheumatoid arthritis? 3 groups (of 50 participants each) were examined for a possible TMD diagnosis: 1. patients with early rheumatoid arthritis, 2. at-risk individuals, and 3. healthy controls. A possible association with bruxism, determined on the basis of self-reporting and clinical features, was also examined. At-risk patients had a higher prevalence of TMD pain diagnoses compared to healthy controls (p = 0.046). Within the early rheumatoid arthritis group, seronegative patients had a higher prevalence of TMD pain diagnoses than seropositive patients (p = 0.048). No further differences in the prevalence of TMD diagnoses were found between the groups. Participants with a TMD pain diagnosis were more often diagnosed with probable sleep bruxism than those without a TMD pain diagnosis. The prevalence of TMD pain is increased in individuals at risk of rheumatoid arthritis and seronegative early rheumatoid arthritis patients, and is associated with signs of bruxism.

ASSOCIATIONS BETWEEN SCREENING FOR FUNCTIONAL JAW DISTURBANCES AND PATIENT REPORTED OUTCOMES ON JAW LIMITATIONS AND ORAL BEHAVIORS.

OBJECTIVES: Temporomandibular disorders (TMDs) is a collective term for pain and functional disturbances related to the jaw muscles and the temporomandibular joint. In contrast to screening for orofacial pain, knowledge is limited on the association between patient-reported outcomes and screening for joint-related functional jaw disturbances. Therefore, our aim was to evaluate the association between a screening question for functional jaw disturbances, and disease-specific outcome measures for functional jaw limitations and oral behaviors. METHODS: This study included 299 individuals (201 women; 20-69 years, median 37.0) in a general population sample from Västerbotten, Northern Sweden in 2014. A single screening question for functional jaw disturbances "Does your jaw lock or become stuck once a week or more?" was used to categorize individuals as cases or controls. Patient-reported outcomes on functional jaw disturbances were assessed with the 20-item jaw functional limitation scale (JFLS-20) and oral behaviors with the 21-item Oral Behaviors Checklist (OBC-21). RESULTS: The strongest predictive probability to have a positive screening outcome was functional jaw limitations related to mobility (AUCboot=0.78, 95 CI:0.71-0.86, P < .001), followed by limitations related to communication (AUCboot = 0.74, 95 CI:0.63-0.80, P < .001) and mastication (AUCboot = 0.73, 95 CI:0.66-0.81, P < .001). The frequency of oral behaviors was not significantly associated with a positive screening outcome (AUCboot = 0.65, 95 CI:0.55-0.72, P = .223). CONCLUSIONS: Self-reported functional limitations, but not oral behaviors, are strongly associated with a single screening question for frequent functional jaw disturbances. This finding provides support for incorporating a question on jaw catching/locking once a week or more in screening instruments for TMDs.

The Longitudinal Relationship between Jaw Catching/Locking and Pain.

Orofacial pain and joint-related dysfunction can negatively affect daily jaw function. A common cause for limitations in jaw movements is joint-related dysfunction such as various forms of catching and locking. However, knowledge is limited regarding the development and natural course of joint-related jaw dysfunction and its relationship to the onset and course of orofacial pain. Therefore, the aim was to evaluate the incidence, prevalence, and gender differences in jaw catching/locking over time and in relation to orofacial pain in the general population. Data from 3 validated screening questions on orofacial pain and jaw catching/locking were collected from all routine dental checkups in the Public Dental Health Services in Västerbotten, Sweden, from 2010 to 2017. Logistic generalized estimating equation was used to account for repeated observations and Poisson regression for incidence analysis. In total, 180,308 individuals (aged 5-104 y) were screened in 525,707 dental checkups. In 2010, based on 37,647 individuals, the prevalence of self-reported catching/locking was higher in women than in men (3.2% vs. 1.5%; odds ratio, 2.11; 95% confidence interval [CI], 1.83-2.43), and this relationship and magnitude remained similar throughout the study period. The annual incidence rate was 1.1% in women and 0.5% in men. Women were at a higher risk than men for reporting both first onset (incidence rate ratio [IRR], 2.29; 95% CI, 2.11-2.49) and persistent (IRR, 2.31; 95% CI, 2.04-2.63) catching/locking. For the onset subcohort (n = 135,801), an independent onset of orofacial pain or jaw catching/locking exclusively was reported by 84.1%, whereas a concurrent onset was reported by 13.4%. Our findings of higher incidence, prevalence, and persistence in women than in men indicate that the gender differences seen for orofacial pain are evident also for jaw catching/locking. The findings also suggest independent onset of self-reported catching/locking and orofacial pain, which reinforces the pathophysiological differences between these conditions.

RECOMMENDATIONS FOR USE AND SCORING OF ORAL HEALTH IMPACT PROFILE VERSIONS.

BACKGROUND: OHIP's original seven-domain structure does not fit empirical data, but a psychometrically sound and clinically more plausible structure with the four OHRQoL dimensions Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact has emerged. Consequently, use and scoring of available OHIP versions need to be revisited. AIM: We assessed how well the overall construct OHRQoL and its four dimensions were measured with several OHIP versions (20, 19, 14, and 5 items) to derive recommendations which instruments should be used and how to score them. METHODS: Data came from the "Dimensions of OHRQoL Project" and used the project's learning sample (5,173 prosthodontic patients and general population subjects with 49-item OHIP data). We computed correlations among OHIP versions' summary scores. Correlations between OHRQoL dimensions, on one hand, and OHIP versions' domain scores or OHIP-5's items, on the other hand, were also computed. OHIP use and scoring recommendations were derived for psychometrically solid but also practical OHRQoL assessment. RESULTS: Summary scores of 5-, 14-, 19- and 49-item versions correlated highly (r = 0.91-0.98), suggesting similar OHRQoL construct measurement across versions. The OHRQoL dimensions Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact were best measured by the OHIP domain scores for Physical Disability, Physical Pain, Psychological Discomfort, and Handicap, respectively. CONCLUSION: Recommendations were derived which OHIP should be preferably used and how OHIP versions should be scored to capture the overall construct and the dimensions of OHRQoL. Psychometrically solid and practical OHRQoL assessment in all settings across all oral health conditions can be achieved with the 5-item OHIP.

[Orofacial pain: a discipline on the brink of a new era]. / Orofaciale pijn: een vakgebied aan de vooravond van een nieuw tijdperk.

The orofacial pain discipline is on the brink of a new era. The introduction of a new definition of pain that, unlike the previous definition, also applies to individuals who cannot verbally express their pain, as well as the publication of the new international classification for orofacial pain, will contribute significantly to the improvement of the quality of the diagnostic process, thus increasing the chance of a successful treatment. Ultimately, the orofacial pain patient will emerge as the winner. The purpose of this article is to introduce the reader to these important recent developments and to provide him/her with an understanding of the implications of these developments for orofacial pain diagnosis and treatment in general and specialized dental practice.

[Singing is not associated with temporomandibular disorders]. / Zingen gaat niet gepaard met kaakklachten.

This research investigated whether vocalists report pain-related forms of temporomandibular disorders (TMDs) and temporomandibular joint (TMJ) sounds more often than musicians who do not load their masticatory system while playing. In addition, we investigated which risk indicators were associated with TMDs among musicians. A total of 1,470 musicians from 50 different music ensembles completed a questionnaire, including 306 vocalists (the group investigated) and 209 musicians who do not load their jaw while playing (the control group). The prevalence of self-reported TMD pain among the vocalists was 21.9%, compared with 12.0% in the control group. 19.6% of the vocalists reported TMJ sounds versus 14.8% of the controls. From the multiple regression model, taking into account the effect of confounders, such as age and gender, singers were not shown to report TMD pain and jaw joint sounds more often than non-singers. Various forms of physical workload were, however, positively associated with the presence of self-reported TMDs among musicians, namely the intensity of harmful oral habits with TMD pain and TMJ sounds, the number of hours of daily practice with TMD pain, and the number of years of playing experience with TMJ sounds.

[The prevalence of tooth wear in the Dutch adult population]. / De prevalentie van gebitsslijtage onder de volwassen Nederlandse bevolking.

This study, performed in 2013, aimed to assess the prevalence of tooth wear in the Dutch adult population. The prevalence of tooth wear was not only determined for different age groups but also according to gender, socioeconomic status and types of teeth. Results were compared with the outcomes of a previous study in a comparable population in 2007. The data were collected as part of a comprehensive dental-epidemiological research project. The 1,125 adults from the city of 's-Hertogenbosch who participated in the project were subdivided into 5 age groups. Tooth wear was quantified using a 5-point ordinal occlusal/incisal grading scale. The number of teeth affected by tooth wear was higher in older age groups. Men showed more tooth wear than women, as did individuals with lower socioeconomic status, among whom a similar tendency was observed. Tooth wear prevalence found in 2013 was higher in all age groups than in 2007. One can conclude that tooth wear is a common condition in the Dutch adult population.

Long-term variability of sleep bruxism and psychological stress in patients with jaw-muscle pain: Report of two longitudinal clinical cases.

Sleep bruxism (SB) and psychological stress are commonly considered as contributing factors in the aetiology of temporomandibular disorder (TMD) pain. However, the lack of longitudinal studies and fluctuating nature of SB, psychological stress and TMD pain have led to contradictory results regarding the association between the possible aetiological factors and TMD pain. In the present study we investigated the contribution of SB and psychological stress to TMD pain in a longitudinal study of 2 clinical TMD pain cases during a 6-week study protocol. Two female volunteers with clinically diagnosed myalgia based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) participated in the study. Questionnaires were used to record jaw-muscle pain and psychological stress experience, and an ambulatory polysomnography technique was used to record SB intensity. Visual analysis of the data revealed that the intensity of TMD pain was not hardwired, neither with psychological stress experience nor with increased SB activity. Within the limitations of single-patient clinical cases design, our study suggested that the presence of TMD pain cannot be explained by a simple linear model which takes psychological stress or SB into account. It also seems that psychological stress was a more important predictor factor for TMD pain than SB.

Evidence-based review on temporomandibular disorders among musicians.

BACKGROUND: Playing a musical instrument that loads the masticatory system has frequently been linked to temporomandibular disorders (TMDs). Previous literature reviews on this topic do not conform to the current standards of evidence-based medicine. AIMS: To investigate the effects of playing a musical instrument (i.e. violin/viola and wind instruments) or singing on the presence of TMDs, based on evidence derived from observational studies. METHODS: Databases of Medline, Web of Science and Google Scholar were searched using MeSH and other relevant terms. For each study, a quality assessment was undertaken using a modified version of the Newcastle-Ottawa Scale (NOS). RESULTS: Fifteen relevant papers were identified for inclusion in this review. Of the seven possible points that could be scored with the NOS, the majority of these studies scored under half. Based on the available evidence, the purported relationship between the playing of specific musical instruments and TMDs was not as evident as reported in previous literature reviews. CONCLUSIONS: There is limited evidence to conclude that playing a wind instrument is a hazard to the temporomandibular system. Furthermore, there is no available evidence to suggest that vocalists experience more TMDs than controls. The studies that investigated the presence of TMDs among violists and violinists yielded ambiguous outcomes; some studies reported no association between the playing of these instruments and the presence of signs and symptoms of TMDs, whereas in studies where a clinical examination was performed (though of lower methodological quality), an association was found.

Outcome of three screening questions for temporomandibular disorders (3Q/TMD) on clinical decision-making.

Patients with temporomandibular disorders (TMD) seem to go undetected and not adequately managed within dentistry. To identify these patients, three screening questions (3Q/TMD) have been introduced within dentistry in parts of Sweden. It is not known whether 3Q/TMD affects the clinical decision-making for these patients. The aim of this study was to evaluate the outcome of 3Q/TMD on the clinical decision-making and to analyse whether gender, age and the fee system the individual was assigned to were related to prescribed TMD treatment. This cohort study was carried out within the Public Dental Health service in Västerbotten, Sweden. As part of the routine dental check-up, a health declaration including 3Q/TMD was completed. The study population was randomly selected based on their 3Q/TMD answers. In total, 300 individuals with an affirmative answer to any of the 3Q/TMD, and 500 individuals with all negative answers were selected. The 3Q/TMD includes questions on weekly jaw-face-temple pain (Q1), pain on function (Q2) and catching/locking of the jaw (Q3). The 3Q/TMD was analysed in relation to prescribed treatment assessed from dental records. There was significantly more treatment performed or recommended for 3Q-positives (21·5%), compared to 3Q-negatives (2·2%) (P < 0·001). The odds ratio for TMD-related treatment for 3Q-positives versus 3Q-negatives was 12·1 (95% CI: 6·3-23·4). Although affirmative answers to the 3Q/TMD was related to TMD treatment, the majority of individuals with a screen positive still did not, according to dental records, receive assessment or treatment. Further studies are needed to better understand the clinical decision-making process for patients with TMD.

Cross-cultural adaptation, reliability and construct validity of the Tampa scale for kinesiophobia for temporomandibular disorders (TSK/TMD-Br) into Brazilian Portuguese.

Fear of movement (kinesiophobia) seems to play an important role in the development of chronic pain. However, for temporomandibular disorders (TMD), there is a scarcity of studies about this topic. The Tampa Scale for Kinesiophobia for TMD (TSK/TMD) is the most widely used instrument to measure fear of movement and it is not available in Brazilian Portuguese. The purpose of this study was to culturally adapt the TSK/TMD to Brazilian Portuguese and to assess its psychometric properties regarding internal consistency, reliability, and construct and structural validity. A total of 100 female patients with chronic TMD participated in the validation process of the TSK/TMD-Br. The intraclass correlation coefficient (ICC) was used for statistical analysis of reliability (test-retest), Cronbach's alpha for internal consistency, Spearman's rank correlation for construct validity and confirmatory factor analysis (CFA) for structural validity. CFA endorsed the pre-specified model with two domains and 12-items (Activity Avoidance - AA/Somatic Focus - SF) and all items obtained a loading factor greater than 0·4. Acceptable levels of reliability were found (ICC > 0·75) for all questions and domains of the TSK/TMD-Br. For internal consistency, Cronbach's α of 0·78 for both domains were found. Moderate correlations (0·40 < r < 0.60) were observed for 84% of the analyses conducted between TSK/TMD-Br scores versus catastrophising, depression and jaw functional limitation. TSK/TMD-Br 12 items and two-factor demonstrated sound psychometric properties (transcultural validity, reliability, internal consistency and structural validity). In such a way, the instrument can be used in clinical settings and for research purposes.

Obesity as a risk factor for temporomandibular disorders.

We conducted a clinical cross-sectional study to evaluate the association between obesity and the presence of painful temporomandibular disorders (TMD), controlling for age, gender, presence of migraine, depression, non-specific somatic symptoms and obstructive sleep apnoea syndrome (OSAS) in an adult population. A total of 299 individuals (76·6% women) with a mean age of 36·8 ± 12·8 years were evaluated. TMD were classified using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Depression and non-specific somatic symptoms were scored by the Symptom Checklist-90, while pain and disability was rated by the Graded Chronic Pain Scale. Bioimpedanciometry (BIA) was used to assess obesity through total body fat percentage. Migraine was diagnosed according to the criteria of the International Classification of Headache Disorders-2 (ICHD-2). OSAS was classified according to the Berlin Questionnaire. We performed univariate and multivariate models, chi-square tests and odds ratios (OR) with 95% confidence intervals (CI). In the single regression analysis, TMD-pain was significantly associated with total body fat percentage (P = 0·01). In the multivariate analysis, migraine, age, non-specific somatic symptoms and OSAS showed to be stronger predictors of TMD-pain, and obesity did not retain in the regression model. The initial association found between obesity and TMD-pain is lost when it was corrected for gender, migraine, non-specific somatic symptoms and OSAS.

Associations of pain intensity and pain-related disability with psychological and socio-demographic factors in patients with temporomandibular disorders: a cross-sectional study at a specialised dental clinic.

The study assessed whether psychological and socio-demographic factors, including somatisation, depression, stress, anxiety, daytime sleepiness, optimism, gender and age, are associated with pain intensity and pain-related disability in patients with temporomandibular disorders (TMDs). In total, 320 TMD patients were involved in the study. The psychological status of each patient was assessed with questionnaires, including the Symptom Checklist-90 (SCL-90), Epworth Sleeping Scale (ESS), stress questionnaire and Life Orientation Test-Revised (LOT-R). TMD pain, including pain intensity and pain-related disability, was assessed with characteristic pain intensity (CPI) and disability points scales. The associations of psychological and socio-demographic factors with pain intensity and pain-related disability were assessed through logistic regression analyses. Higher pain intensity was significantly associated with more severe anxiety (P = 0·004), more severe somatisation (P < 0·001), more severe depression (P < 0·001), more severe stress (P = 0·001) and lower optimism (P = 0·025) in univariate regression analyses. However, multiple regression analysis showed that only somatisation was significantly associated with pain intensity (P < 0·001). Higher pain-related disability was significantly associated with more severe anxiety (P < 0·001), more severe somatisation (P < 0·001), more severe depression (P < 0·001), more severe stress (P < 0·001) and lower optimism (P = 0·003) in univariate regression analyses. However, multiple regression analysis showed that only depression was significantly associated with pain-related disability (P = 0·003). Among the psychological and socio-demographic factors in this study, somatisation was the best predictor of pain intensity, while depression was the best predictor of pain-related disability.

[Painful temporomandibular dysfunctions: diagnosis and -treatment]. / Pijnlijke temporomandibulaire disfuncties: diagnose en behandeling.

Painful temporomandibular disorders (TMD pain) are common among the general population. The most common sub diagnoses are myalgia (jaw-muscle pain) and arthralgia (temporomandibular joint pain). The aetiology of TMD pain has a multifactorial nature, and its diagnosis and possible treatment often require a multidisciplinary approach. The most recent insights in the diagnosis and treatment of TMD pain are based on the multidisciplinary guideline 'Chronic Orofacial Pain' that was developed by the Dutch Society of Headache Patients and was published in 2013. Dentists are required to follow the recommendations of this guideline. The authorisation of the guideline by the relevant academic and professional associations in the Netherlands implies that restraint is advised when adopting diagnostic procedures and treatment modalities that are not or are insufficiently based on solid evidence.

Validity of three screening questions (3Q/TMD) in relation to the DC/TMD.

Temporomandibular disorders (TMD) are common but seem to be largely undetected within general dental care. To improve dentists' awareness of these symptoms, three screening questions (3Q/TMD) have been introduced. Our aim was to validate 3Q/TMD in relation to the diagnostic criteria for TMD (DC/TMD), while taking into account the severity level of the symptoms. The study population consisted of 7831 individuals 20-69 years old, who had their routine dental check-up at the Public Dental Health Service in Västerbotten, Sweden. All patients answered a health declaration, including the 3Q/TMD regarding frequent temporomandibular pain, pain on movement and catching/locking of the jaw. All 3Q-positives (at least one affirmative) were invited for examination in randomised order. For each 3Q-positive, a matched 3Q-negative was invited. In total, 152 3Q-positives and 148 3Q-negatives participated. At examination, participants answered 3Q/TMD a second time, before they were examined and diagnosed according to DC/TMD. To determine symptom's severity, the Graded Chronic Pain Scale and Jaw Functional Limitation Scale-20 (JFLS-20) were used. In total, 74% of 3Q-positives and 16% of 3Q-negatives met the criteria for DC/TMD pain or dysfunction (disc displacements with reduction and degenerative joint disorder were excluded). Fifty-five per cent of 3Q-positives had a TMD diagnosis and CPI score ≥3 or a JFLS-20 score ≥5, compared to 4% of 3Q-negatives. The results show that the 3Q/TMD is an applicable, cost-effective and valid tool for screening a general adult population to recognise patients in need of further TMD examination and management.

Assessment of the amount of tooth wear on dental casts and intra-oral photographs.

Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Many grading scales are available to assess the amount of tooth wear, one of which is the tooth wear evaluation system (TWES). A grading scale can be used chairside, on casts and on photographs. The aim was to test whether the grading scales of the TWES, used on casts and on photographs, resulted in comparable scores. In addition, it was tested whether these scales can be used to assess tooth wear reliably on photographs. Of 75 tooth wear patients, sets of casts and series of photographs were obtained and graded. Comparison of the grading on casts and on photographs revealed equal median values and percentiles for both occlusal/incisal grading and non-occlusal/non-incisal grading. The grading on casts and on photographs showed a high correlation for the occlusal/incisal grading and a low correlation for the non-occlusal/non-incisal grading (Spearman's rho = 0·74 and rho = 0·47; P < 0·001). Concerning the grading on photographs, the interexaminer reliability was fair-to-good (ICC = 0·41 to ICC = 0·55) while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·68 to ICC = 0·86) for the occlusal/incisal grading. For the non-occlusal/non-incisal grading, the interexaminer reliability was poor to fair-to-good (ICC = 0·22 to ICC = 0·59), while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·64 to ICC = 0·82). It was concluded that the scores obtained with the grading scales of the TWES on casts and on photographs are comparable. The grading scales can be used in a reliable way on photographs, which is especially the case for occlusal/incisal grading.

Temporomandibular pain and jaw dysfunction at different ages covering the lifespan--A population based study.

BACKGROUND: Temporomandibular pain and jaw dysfunction can have a negative effect on daily life, but these conditions are not well recognized in the health care systems. The general aim was to examine the cross-sectional prevalence of frequent temporomandibular pain and jaw dysfunction in men and women across the lifespan. METHODS: The analysis was based on data from 137,718 individuals (mean age 35 years, SD 22.7) who answered three questions (3Q/TMD) included in the digital health declaration in the Public Dental Health care in the county of Västerbotten, Sweden; Q1: 'Do you have pain in your temple, face, jaw or jaw joint once a week or more?'; Q2: 'Does it hurt once a week or more when you open your mouth or chew?'; and Q3: 'Does your jaw lock or become stuck once a week or more?' RESULTS: The prevalence of frequent temporomandibular pain (Q1) was 5.2% among women and 1.8% among men (p < 0.0001). The prevalence of frequent pain on jaw movement (Q2) was 2.5% among women and 0.9% among men (p < 0.0001). The prevalence of frequent locking of the jaw (Q3) was 2.7% among women and 1.2% among men (p < 0.0001). CONCLUSIONS: The study shows that the cross-sectional prevalence of temporomandibular pain and jaw dysfunction varies during the lifespan. For men and women, respectively, symptoms increase during adolescence, peak in middle age and then gradually diminish. The prevalence of these symptoms is significantly higher among women except from the first and last decades of a 100-year lifespan.

Psychometric properties of the Dutch version of the Orofacial Esthetic Scale (OES-NL) in dental patients with and without self-reported tooth wear.

The aim of this study was to test the psychometric properties of the Dutch version of the Orofacial Esthetic Scale (OES) in dental patients with and without self-reported tooth wear. The English version of the OES was translated into Dutch, following established guidelines for cross-cultural adaptation of health-related quality of life measures. The reliability of the resulting OES-NL was tested in a test-retest study on 343 subjects; its validity was tested with the use of convergent validity on 582 subjects. The test-retest reliability of the OES-NL showed intra-class correlation coefficients (ICC) that ranged from 0·76 to 0·82, which can be qualified as excellent. The Cronbach's alpha revealed that the overall internal consistency of the scale was good (α = 0·89). Convergent validity was confirmed by the association between the OES-NL summary scores and three questions of the Dutch version of the Oral Health Impact Profile (OHIP-NL). The calculated Spearman's rank correlation coefficients ranged from -0·43 to -0·54 and were all significant (P < 0·001). The Dutch version of the Orofacial Esthetic Scale (OES-NL) showed good psychometric properties, making it suitable for the assessment of self-perceived aesthetics in Dutch dental patients with and without self-reported tooth wear.