Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 11  |  Issue : 1  |  Page : 16-26

Common Knowledge About Temporomandibular Disorders and Associated Factors With Its Symptoms: Evidence From a Portuguese Population-Based Survey


1 CESPU, Instituto de Investigacão e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central de Gandra, Gandra, Portugal
2 CESPU, Instituto de Investigacão e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central de Gandra, Gandra; Escola Superior de Saúde de Santa Maria, Travessa Antero de Quental, Portugal
3 CIAFEL, Faculdade de Desporto da Universidade do Porto, Rua Dr. Plácido Costa, Portugal
4 CESPU, Instituto de Investigacão e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central de Gandra, Gandra; IBMC – Inst. Biologia Molecular e Celular, i3S - Inst. Inovação e Investigação em Saúde, Universidade do Porto, Porto, Portugal

Date of Web Publication9-Aug-2019

Correspondence Address:
Teresa Pinho
Instituto de Investigacão e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central de Gandra, 1317, 4585-116 Gandra PRD, Portugal
Portugal
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jofs.jofs_142_18

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  Abstract 


Introduction: The purpose of this article was to develop and validate a scale to assess common knowledge about temporomandibular disorders (TMDs) in the general population, evaluate the status of TMDs knowledge in the Portuguese population, quantify the severity and prevalence of TMDs-related symptoms in the general population, and assess the association between TMDs-related symptoms’ severity and demographic, medical and oral associated factors. Materials and Methods: This study was an analytical cross-sectional survey design. The sample consisted of 2165 participants selected through a snowball sampling method. The participants completed an online questionnaire regarding social and demographic characteristics, medical history, oral habits, Fonseca’s Anamnestic Index, a scale about difficulties on impulsiveness control and also the TMDs knowledge scale developed. The psychometric properties of the scale developed was tested on a small number of participants (n = 210). The P value set was 0.05. Results: Concerning psychometric properties all items showed a moderate-to-strong positive association with the loading factor. The Cronbach’s alpha was 0.956, showing good reliability. TMDs knowledge was positive in 1295 participants (59.8%). Multivariate-adjusted odds showed that female gender, diagnosis of tension-type headache, migraine, anxiety, impulsiveness, facial trauma, and parafunctional habits increased the risk of developing TMDs (adjusted odds ratios from 1.84 to 49.38). Conclusion: The scale developed is psychometrically valid and reliable and the participants had an overall positive knowledge about TMDs. A high prevalence of TMDs-related symptoms among the Portuguese population was found and the associated factors were female gender, impulsiveness, tension-type headache, migraine, anxiety, facial trauma, and parafunctional habits.

Keywords: Epidemiology, health literacy, health education, scale validation, temporomandibular joint disorders


How to cite this article:
Paco M, Simões D, Chaves P, Almeida V, Rocha JC, Moreira L, Duarte JA, Pinho T. Common Knowledge About Temporomandibular Disorders and Associated Factors With Its Symptoms: Evidence From a Portuguese Population-Based Survey. J Orofac Sci 2019;11:16-26

How to cite this URL:
Paco M, Simões D, Chaves P, Almeida V, Rocha JC, Moreira L, Duarte JA, Pinho T. Common Knowledge About Temporomandibular Disorders and Associated Factors With Its Symptoms: Evidence From a Portuguese Population-Based Survey. J Orofac Sci [serial online] 2019 [cited 2019 Aug 25];11:16-26. Available from: http://www.jofs.in/text.asp?2019/11/1/16/264182




  Introduction Top


The American Academy of Orofacial Pain defines temporomandibular disorders (TMDs) as a group of musculoskeletal and neuromuscular conditions that involve the temporomandibular joints (TMJs), the masticatory muscles, and all associated structures.[1] Prevalence rates ranges from 10% to 25% of the population[2],[3] being the most common chronic orofacial pain condition. Notwithstanding its etiology is not yet well known and is considered to be multifactorial.[1] Several contributing factors have been described, such as morphological, neuromuscular, occlusal, psychological, genetic and parafunctional habits among others.[4],[5],[6],[7],[8] Another potential risk factor proportionally related with health status, not often reported in the literature but highly advocated by the World Health Organization, is the level of literacy about the medical condition.[9] There is a growing concern about the identification of health determinants, not only by the different political and social entities, but mainly by the medical and scientific community. This raising concern about the identification of health determinants has shown that the level of knowledge and literacy is a factor proportionally related with the health level.[10] This determinant was defined by the World Health Organization as the cognitive and social skills of the individual that determine the motivation and ability to access, understand, and effectively use the information, as a strategy of health promotion and maintenance.[9] Health knowledge is an important trigger to change behaviors and attitudes[11] and contributes to the improvement of individuals’ and populations’ health.[12] Furthermore, concerning the ability of developing strategies to health maintenance and self-management, knowledge acts as an empowerment tool.[10],[13] The biopsychosocial model reinforces the importance of empowering the patient through knowledge about diagnosis, prognosis and the nature of the problem, to involve the patient in the disease management, namely in therapeutic decision, especially regarding chronic conditions.[14] Adequate information has shown to provide self-management skills and better coping strategies in rheumatoid arthritis patients as well as compliance to therapy and treatment success.[15],[16]

Thus, it becomes fundamental to ascertain the levels of individual and collective knowledge about potential health pathologies known to represent a health problem, to define strategic actions and organize literacy/education health programs, intended to influence individual and/or collective lifestyle decisions, allowing to explore the influence of this health determinant and modify its impact. Having this, as there are no validated instruments to determine the level of knowledge about TMDs, to our knowledge, and considering that the different etiologies described in the literature need further highlighting and remain as a subject of disagreement among researchers, conditioning the establishment of effective treatment plans,[17] this study had the following objectives: to develop and validate a scale to assess common knowledge about TMDs in the general population, evaluate the status of TMDs knowledge in the Portuguese population, quantify the severity and prevalence of TMDs-related symptoms in the general population, and assess the association between TMDs-related symptoms’ severity and demographic, medical and oral associated factors.


  Materials and Methods Top


Study design

This is an analytical cross-sectional, survey design where a snowball sampling was applied and intended to recruit participants not only from health-related professions but also from the general population. Exclusion criteria were age lower than 18 years and not Portuguese citizens. Because this was an online questionnaire, informed consent of the participants was obtained by having a first affirmation that the participant should select, acknowledging that the participant accepts to take part in the study. This study was approved by the Ethical Committee of IUCS (CEI) (3/CE-IUCS/2016).

This study was divided in two moments. The first moment encompassed the development and validation of the TMDs knowledge scale, and the second moment the assessment of the level of knowledge about TMDs and the assessment of TMDs-related symptoms’ prevalence and associated factors.

TMDs knowledge scale

To develop the scale, an experts’ committee was created that included one lay person and eight health professionals as follows: one doctor, one orthodontist, one dentist, four physiotherapists, and one psychologist. The TMDs knowledge scale was developed in two phases: concept analysis and construction (item development and identification of domains and pilot testing on a small number of participants) and testing the psychometric properties.

Concept analysis and construction (item development)

Items were generated through a multistep process: literature review; experts meeting; item selection and writing; pilot testing of the questionnaire; examination by the experts’ committee; and final item selection and writing.

The relevant scientific literature research was conducted using electronic databases (Pubmed/Medline, Embase), and information regarding prevalence data, diagnosis, pathophysiology, comorbidities, and psychosocial factors associated with TMDs was acquired. Concerning any other questionnaire or scale regarding the assessment of TMDs knowledge for the general population, we have not found any instrument described in the literature. After this, the experts’ committee met together and selected the items to be included in the questionnaire and, more specifically, the construct concept of the TMDs knowledge scale. After items generation, a consensus about the items to include was reached between the experts’ committee. The scale consisted of 21 items that were assessed through a three-level Likert scale (“correct answer,” “wrong answer,” and “I do not know”) whether each item is related with TMDs. After this, a pilot study was conducted with a total of 10 participants that fulfilled the self-administered questionnaire and were asked to identify any problems regarding questions interpretation, clarity, and objectivity.

After gathering all the information, the experts’ committee reached a consensus regarding the final version of the scale. This scale was part of a questionnaire, wherein the participants were asked about social and demographic characteristics, medical history, oral habits (bruxism, nails biting, gum chewing, and any other parafunctional habit), Fonseca’s Anamnestic Index (FAI), and an impulsiveness control scale. The questionnaire was built in an online survey software (Qualtrics, Provo, UT, USA) and the link to the survey was sent to e-mail lists and through online social networks, asking every participant to invite others to participate in the study (by sharing the link to the questionnaire).

Psychometric validation of TMDs knowledge scale

To validate the TMDs knowledge scale, a sample comprising 210 individuals was used. The participants were recruited according with the criteria listed mentioned in the previous section, and the answers to the online questionnaire were analyzed.

TMDs knowledge assessment and the assessment of TMDs-related symptoms’ prevalence and associated factors

As described in the previous section, the complete questionnaire (encompassing questions regarding social and demographic characteristics, medical history, oral habits, FAI, an impulsiveness control scale, and TMDs knowledge scale) was built in an online survey software (Qualtrics) and the link to the survey was sent to e-mail lists and through online social networks.

FAI

FAI is a low-cost and easy-to-apply instrument proposed in the Portuguese language, consisting of 10 questions whose answers are arranged in a three-point scale format (“No,” “Sometimes,” “Yes”). It is used to classify individuals according to TMDs severity (score 0–15: “TMDs free,” score 20–40: “Mild TMDs,” score 45–60: “Moderate TMDs,” and score 70–100: “Severe TMDs”), and also to screen patients for further developments in diagnosing TMDs. Its main advantages are the simplicity of its application and the fact that it does not need a physical examination of the patient, which makes it suitable for fast epidemiological screening by telephone, mail, or internet survey,[18] as in our study.

Difficulties on impulsiveness control scale

This scale evaluates the difficulties in controlling impulsiveness and is a subscale from difficulties in emotion regulation scale (DERS)[19] composed by six items. The DERS is a measure of the difficulties of emotional regulation in a fully covering and comprehensive way, with 36 items, evaluating the frequency of feelings on a scale from 1 (almost never) to 5 (almost always). The scale items were organized in six factors: strategies, nonacceptance, awareness, impulse, goals, and clarity. The final result of DERS reflects the flexibility of the individual on emotional regulation strategies use, effective and appropriate to the situation.[20] In the original version of the DERS, the internal consistency was α = 0.93 and the Portuguese validation study was α = 0.92.[21] The subscale “impulse” score ranges between 6 and 30, where a highest score represents a higher difficulty in controlling impulsiveness.

Statistical analysis

Statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS), version 24 (IBM® company, Chicago, IL, USA). The factor structure was investigated using an exploratory factor analysis (i.e., principal component analysis) with orthogonal rotation, by use of the Varimax method. The number of factors for extraction was based on Kaiser’s eigenvalue criterion (eigenvalue ≥1) and evaluation of the scree plot. After selecting the number of factors to be retained, a factorial matrix was generated, in which the relationships between the items and the factors were observed via factor loadings. Factor loading over 0.3 was considered as appropriate. Sampling adequacy was assessed by using the Keiser-Meyer Olkin test (KMO) and the Bartlett’s test of sphericity. The standardized Cronbach’s alpha was estimated to evaluate the internal consistency of the group of items.

Descriptive statistics comprised the following: counts and proportions, mean and standard deviation, or median and interquartile range (IQR). For the assessment of TMDs knowledge, the final score was obtained by assigning one point for each correct answer, with a possible maximum score of 21 points. To assess the construct validity, results were compared by education level, TMDs global awareness (have already heard about TMDs), TMDs professional awareness (have a profession where TMDs knowledge is expected), and TMDs severity (evaluated through FAI). Mann-Whitney and Kruskal Wallis tests were used to compare the score between two or three independent groups, respectively. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) were computed to test the association between positive TMDs knowledge and the potential predictive factors that can be used to predict TMDs knowledge in the general population.

Regarding associated factors analysis, sample characteristics are presented as counts and proportions for categorical variables and median and IQR for age and impulsiveness scale, as normal distribution was not confirmed. Chi-square and Kruskal Wallis tests were used to compare proportions and continuous variables, respectively. A multinomial logistic regression was used to assess the association of putative determinants with the outcome. Crude and adjusted ORs and 95% CIs were computed, taking participants without TMDs-related symptoms as the reference category of the outcome. From a list of a priori potential determinants, a final model was conducted comprising only variables associated with the outcome, even after adjustment. The critical value for significance in all the analysis was P value <0.05.


  Results Top


Development of the TMDs knowledge scale

As mentioned previously, the development of the scale comprised initially a comprehensive literature review of the relevant publications on the topic. Twenty-one items were developed by the main researchers in accordance to the main areas of importance for the patient’s education. The items were divided according to the content proposed as follows: TMDs epidemiology, risk factors, signs and symptoms, and treatment. Each question was presented with three multiple-choice alternatives, as follows: “correct answer,” “wrong answer,” and “I do not know.”

The scale was presented in the experts’ committee and each health professional provided their opinion about the content and clarity of each item. Some items generated comments regarding content and semantics. The suggested changes were implemented. The second version of the scale was individually validated by each experts’ committee member. Additionally, 10 individuals completed the questionnaire as described, and referred to each set of question/answer regarding understanding and clarity. No relevant questions were addressed.

TMDs knowledge scale psychometric characteristics

This scale was pilot tested in a sample of 210 participants (21 items x 10 participants per item). As no item was missing and no outlier existed, no cases were deleted from the dataset. The mean age was 30.3 ± 8.44 years, 119 (56.7%) were women, 123 (58.6%) had more than 12 years of education, 136 (64.8%) had already heard about TMDs, and 58 (27.6%) had a profession wherein TMDs knowledge is expected, such as dentists, stomatologists, physiotherapists, and speech therapists, among others. Eighty-seven participants (41.4%) reported having no TMDs (FAI score ≤ 15), 73 (34.8%) had mild TMDs (FAI score 20–40), 38 (18.1%) had moderate TMDs (FAI score 45–65), and 12 (5.7%) had severe TMDs (FAI score ≥ 70).

The proportion of individuals that correctly answered each item ranged from 24.8% (items 5 and 15) to 70% (item 7). As no prior information on the number of factors to be held was available, exploratory factor analysis was performed. In total, four factor analyses were conducted. During the first three analyses, several items did not fulfill the criteria of loading significantly and exclusively on an appropriate factor and due to this fact a one-factor solution emerged. This one-factor solution was globally interpreted as TMDs knowledge. The KMO test and the Bartlett’s test of sphericity showed that the data were adequate for factorial analysis (KMO = 0.952 and Bartlett had a P < 0.001). This factor accounted for 56.9% of the total variance of the items (initial eigenvalues 11.94). All items showed a moderate-to-strong positive association with the loading factor. The Cronbach’s alpha was 0.956, showing good reliability, and did not improve if items were deleted [Table 1].
Table 1 Proportion of correct answers, factor Loadings, and Cronbach’s alpha (n = 210)

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TMDs knowledge in the Portuguese population and the assessment of TMDs-related symptoms’ prevalence and associated factors

A sample of 2165 Portuguese citizens aged over 18 years (mean age: 30.1 ± 10.58 years, females: 67.4%) retrieved the online questionnaire complete, and formed the sample of our study [Table 2]. All the Portuguese districts were represented in our sample, with the lowest rate response being from Évora (n = 5) and the highest from Porto (n = 1052).
Table 2 Participants’ characteristics, according to TMDs’ severity (n = 2165)

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The median score of TMDs knowledge in the Portuguese population was 13.0 points (interquartile range: 10.0). Three hundred thirty-four participants (15.4%) had 0 correct answers, whereas 18 participants (0.8%) had 21 correct answers. TMDs knowledge was positive (equal or above 11 correct answers) in 1295 participants (59.8%). The median score of TMDs knowledge was 11.0 points (interquartile range: 15.0). Thirty-eight participants (18.1%) had the lowest score, whereas two participants (1.0%) had the highest score. [Table 3] shows that TMDs knowledge was significantly higher in individuals with higher education, higher TMDs global and professional awareness, and higher TMDs severity.
Table 3 Score of the questionnaire by education level, TMDs global and professional awareness, and history of TMDs (n = 210)

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A logistic regression model was used to identify the potential predictive factors that can be used to predict TMDs knowledge in the general population. Results showed that females, who have already heard about TMDs, have a profession wherein TMDs knowledge is expected and have moderate or severe TMDs-related symptoms had significantly higher TMDs knowledge, even after adjustment to the other predictive factors [Table 4].
Table 4 Association between positive TMDs knowledge and sample characteristics (n = 2165)

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Overall, 1413 participants (65.3%) were identified as having TMDs-related symptoms according to FAI (score ≥ 20). Considering TMDs-related symptoms’ severity, 39.7% participants reported having mild TMDs (FAI score 20–40), 18.1% had moderate TMDs (FAI score 45–65), and 7.5% had severe TMDs (FAI score ≥ 70). In this sample, participants without TMDs were the oldest, with a median (IQR) age of 29.0 (16.0) years, whereas participants with severe TMDs were more impulsive, with a median (IQR) on the impulsiveness scale of 10.0 (6.0). Compared to those without TMDs-related symptoms, participants with TMDs-related symptoms were more often female and had more diagnosis of tension-type headache, migraine, depression, anxiety, and obsessive–compulsive disorder (OCD). The prevalence of these diagnosis seems to be increasing along TMDs severity. Regarding dental history, the presence of facial trauma, parafunctional habits, and orthodontic treatments were higher among participants with TMDs. Third molar extraction was higher among those with severe TMDs-related symptoms but not in those with mild or moderate TMDs-related symptoms [Table 2].

In the crude analysis, and compared to participants without TMDs-related symptoms, lower age and higher impulsiveness were associated with a higher likelihood of having TMDs-related symptoms, regardless of severity. Female gender and a diagnosis of tension-type headache, migraine, depression, or anxiety was associated with a higher probability of having TMDs-related symptoms, with this association being stronger with increased severity. OCD diagnosis was only associated with severe TMDs. Regarding oral characteristics, we observed that participants with history of facial trauma had more chances of having TMDs-related symptoms, regardless of severity. Also, the presence of parafunctional habits was associated with a higher likelihood of TMDs severity. The existence of an orthodontic treatment increased the odds of having moderate or severe TMDs-related symptoms, whereas third molar removal only increased the odds of having severe TMDs-related symptoms [Table 5].
Table 5 Crude OR for the association between demographic, medical, and oral characteristics, according to TMDs severity (n = 2165)

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[Table 6] presents the results of the multivariate analysis. Female sex, impulsiveness, and the presence of tension-type headache, migraine, depression, anxiety diagnosis, facial trauma, or parafunctional habits were associated with a higher probability of having mild, moderate, or severe TMDs-related symptoms, even after adjustment to each other. While impulsiveness and the presence of facial trauma seem to be associated with the presence of TMDs-related symptoms, regardless of severity, all the other characteristics seems to have an association with TMDs severity, since we found a stronger association in higher TMDs severity categories, independently of confounders. Parafunctional habits and tension-type headache diagnosis have the strongest associations with TMDs severity.
Table 6 Multivariate-adjusted odds ratio for the association between demographic, medical, and oral characteristics, according to TMDs severity (n = 2165)

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  Discussion Top


The present study describes a methodological approach to the development and validation of a new self-administered scale to measure the knowledge about TMDs. Our results demonstrate that the scale developed is psychometrically valid and reliable. The TMDs knowledge scale was developed in Portugal, notwithstanding, as it does not contain items that are specifically related to Portuguese culture, it could be translated and used abroad. Moreover, the scale has shown to be easy to understand and complete, and requires a relatively short time to answer.

Since the first step in the development of educational actions is to identify the need for information on what patients really know about their own disease, this study demonstrated an overall positive knowledge of the sample studied. As expected, the individuals with higher professional awareness had higher knowledge about TMDs. This may be justified by the fact that the knowledge scale developed intended to evaluate the general population’s knowledge about TMDs, which means that the statements of the scale were not too technical nor requiring advanced knowledge about the topic. This could explain the difference between our results and the results from studies assessing the knowledge of specific health professionals that reveal lack of knowledge from the professionals.[22]

The participants with self-reported higher TMDs severity of related symptoms had also higher knowledge about the condition. This can be explained by the fact that the impact of TMDs in these participants is higher, which may lead to the search of more information about the condition and its management. Regarding the prevalence and severity of TMDs-related symptoms, based on the FAI, our results showed that 65.3% of the participants were classified as having TMDs-related symptoms, which is according with the literature. Similar prevalence rates have been found among students[23] that may be related with the stressful demands on this population related to the study, responsibility and, expectations. Notwithstanding, these results should be interpreted with caution as the non-TMDs population may also present some signs and/or symptoms of TMDs.

The results concerning associated factors are consistent with the findings of the previous studies in other populations[3],[24],[25] and support the multifactorial etiology proposed and accepted by the scientific community. Furthermore, this study has looked for factors not previously described as impulsiveness and has also retrieved results regarding factors with conflicting evidence in the literature, contributing to a better understanding of the risk factors to develop TMDs. Female gender, facial trauma, parafunctional habits, and psychological factors are frequently reported risk factors.[5],[6],[8],[17],[26],[27] Our results show a higher prevalence and a higher risk for women to develop TMDs-related symptoms, which is in accordance with the other studies and may have biological, social, and behavioral causes, consistent with the biopsychosocial model.[3],[25] This may suggest a possible link between TMDs’ pathogenesis and the estrogen.[28],[29],[30] Literature has shown that women present more sensitivity to most of pain modalities, suggesting a possible link between TMDs and the mechanisms of pain modulation.[30],[31]

When the risk of developing severe TMDs were analyzed, the presence of psychosocial factors like impulsiveness, anxiety, depression, and OCD were found to represent a high risk to develop it. Several studies have shown that psychological–psychiatric problems seem to be associated with TMDs, with patients having psychological–psychiatric problems being more prone to TMDs than individuals without these problems[32],[33] and that anxiety is intrinsically associated with an increase of the odds for pain-related TMDs by the factor 1.04.[24] Moreover, emotion regulation-related disorders such as anxiety–depressive disorders, somatization, and catastrophizing seem to contribute to chronic TMDs, mainly in the form of myofascial pain.[33] Considering our results, the specific underlying psychosomatic factor is associated with the ability to regulate high emotional activation. Similarly with other studies, our results have shown that the presence of parafunctional habits increased the risk of developing TMDs. Parafunctional habits are sought to contribute to TMD because they can be considered a form of repetitive microtrauma that results in pain.[34] Furthermore, this can be related with psychological issues, once disorders related to stress, anxiety, and depression seem to intensify parafunctional activity that may lead to the onset or exacerbation of TMDs.[33]

Other factor that has been reported in the literature is third molar removal which is in accordance with the results we have found.[35] One possible explanation may be the procedure involved in the removal of the third molar, once it implies a wide opening of the mouth, for a considerable long period and associated with forces applied over the mandible, beyond its normal range of motion. This may constitute a trauma to the TMJ or even to the mastication muscles, and, because it is performed under anesthesia, may be accompanied by a reduction in the protective mechanisms of the person under treatment. The presence of facial trauma also increased the odds of developing TMDs-related symptoms, independently of its severity. It is well known that significant forces transmitted to the soft tissues of the TMJ and supporting structures can result in severe dysfunction.[36]

The presence of tension-type headache was found to be strongly associated with TMDs-related symptoms. Headache is one of the most common symptoms of TMDs patients,[37],[38] whereas 55% of chronic headache patients referred to a neurologist had signs or symptoms of TMDs.[39] Myofascial pain has been purported to play a key role in the establishment of tension-type headaches.[40]

All these contributing factors for TMDs make difficult the correct assessment of the disease, which demonstrates the need to understand the physical and psychological characteristics of an individual patient. Hence, the degree of contribution of the different factors to TMDs may be related to individual differences among people and should be further studied.

All data analyzed in our study were collected from a self-administered questionnaire that relied on memory and self-reporting of the participants. Having this in mind, the authors recognize that there might have been incorrect answers to the questions, but due to the high rate of response, the impact of this possible bias is very low. Another limitation of this study is the absence of a clinical examination and laboratory findings for TMDs diagnoses of the participants. Instead, we have used a valid and reliable questionnaire (FAI) often used for epidemiological studies on TMDs that allowed to characterize the signs and symptoms of TMDs and get a score about TMDs severity. Future studies should perform the clinical assessment of the participants, to perform the diagnose of TMDs. Once this was a cross-sectional study, no etiological conclusions can be drawn and the reader should have in mind that no clinical confirmation of the data retrieved by the participants was available. Although our study provided information regarding the prevalence and severity of TMDs in the general Portuguese population, long-term clinical studies should be performed to complement and confirm our data. A significant point to be learned is the need to be aware of the several risk factors for TMDs that translate the need for a thorough and early diagnosis as well as a preventive action of future complications associated with TMDs. These may play a key role in the success of TMDs treatment.


  Conclusion Top


The results from our study showed that the TMDs knowledge scale developed is psychometrically valid and reliable. It also demonstrated that the participants had an overall positive knowledge about TMDs and that females, which have already heard about TMDs, have a profession where TMDs knowledge is expected, and have moderate or severe TMDs-related symptoms had significantly higher TMDs knowledge. It also showed a high prevalence of TMDs among the Portuguese population and that the risk factors found to be associated with TMDs-related symptoms were female gender, impulsiveness, tension-type headache, migraine, anxiety, facial trauma, and parafunctional habits.

Acknowledgements

The authors thank CIAFEL (Research Centre in Physical Activity, Health and Leisure) and IINFACTS (Institute of Research and Advanced Training in Health Sciences and Technologies).

Financial support and sponsorship

PTDC/MEC NEU/29468/2017.

Conflicts of interest

There are no conflicts of interest.



 
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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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