The relationship between orthodontic treatment and temporomandibular disorders: A dental specialists’ perspective

ABSTRACT Introduction: The relationship between temporomandibular disorders (TMDs) and orthodontic treatment/malocclusion has changed from a cause-and-effect association to an idea without sufficient evidence. Objective: This survey was designed to assess the beliefs of different disciplines - orthodontists, oral surgeons, and oral medicine specialists - on the relationship between TMDs and orthodontic treatment, with regard to treatment, prevention and etiology of TMDs. Method: A survey in the form of questionnaire was designed and distributed to 180 orthodontists, 193 oral surgeons and 125 oral medicine specialists actively involved in treating TMDs. The questionnaire aimed to collect basic information about each participant and their beliefs, and clinical management of patients with TMDs. Results: Halve of the responding orthodontists and most of the oral surgeons (69.9%) were male participants, whereas the majority of oral medicine specialists (83.3%) were female respondents. The participants’ age ranged from 29 to 58 years. The majority of orthodontists believes that there is no relationship between orthodontic treatment and TMDs, and that orthodontic treatment does not provoke TMDs or prevent the onset of the disorder. However, oral surgeons and oral medicine specialists have different and conflicting opinions. Most surgeons tended to treat those patients, while most of the other two disciplines tended to seek an interdisciplinary approach. Chi-square test was done to find an association between the referral status and specialists’ experience, and to compare between the different disciplines’ belief. Conclusions: Orthodontist’s beliefs were in accordance with the scientific evidence, whereas most oral surgeons and oral medicine specialist believed that orthodontic treatment may provoke TMDs. Therefore, continuing program series development is important to embrace the concept of the multidisciplinary team approach and improve the health care and quality of life for those patients.


RESUMO
Introdução: A relação entre as disfunções temporomandibulares (DTMs) e o tratamento ortodôntico/más oclusões teve como base uma associação de causa e efeito, e acabou migrando para um conceito sem evidência suficiente. Objetivo: A presente pesquisa foi desenhada para avaliar as crenças de diferentes especialidades -ortodontistas, cirurgiões bucomaxilofaciais e especialistas em Medicina Oral -, sobre a relação entre DTMs e a terapia ortodôntica, quanto ao tratamento, prevenção e etiologia das DTMs. Métodos: Foi feito um levantamento em formato de questionário, enviado para ortodontistas, cirurgiões bucomaxilofaciais e especialistas em Medicina Oral (180, 193 e 125, respectivamente) envolvidos ativamente no tratamento de DTMs. O questionário teve como objetivo coletar informações básicas sobre cada profissional, suas crenças e a conduta clínica em pacientes com DTM. Resultados: Metade dos ortodontistas que responderam e a maioria dos cirurgiões bucomaxilofaciais (69,9%) eram homens, enquanto a maioria dos especialistas em Medicina Oral (83,3%) era de mulheres. A idade dos participantes variou de 29 a 58 anos. A maioria dos ortodontistas acredita que não há relação entre tratamento ortodôntico e DTMs, e que o tratamento ortodôntico não provoca DTMs ou evita o aparecimento da disfunção. No entanto, cirurgiões bucomaxilofaciais e especialistas em Medicina Oral apresentam ideias diferentes e conflitantes. A maioria dos cirurgiões tendeu a tratar esses pacientes, enquanto a maioria das outras especialidades apresentou a tendência de buscar uma abordagem multidisciplinar. O teste do qui-quadrado foi realizado para encontrar uma associação entre a quantidade de encaminhamentos e a experiência dos especialistas, e para realizar uma comparação entre as crenças das diferentes especialidades. Conclusões: A crença dos ortodontistas esteve em acordo com a evidência científica, enquanto a maioria dos cirurgiões e dos especialistas em Medicina Oral acredita que o tratamento ortodôntico pode provocar DTMs. Dessa forma, o desenvolvimento de programas de educação continuada é importante para reforçar a necessidade da abordagem multidisciplinar e melhorar os cuidados orais e a qualidade de vida desses pacientes. Common symptoms of TMDs include headache, facial pain, jaw dysfunction and TM pain. 5,6 It was believed that there is similarity between TMDs pain and lower back pain, considering individual variation in pain perception. Since there is a strong relationship between TMDs and occlusion, changing the position of teeth and altering the existing occlusion via orthodontic appliances has drawn many investigations and controversial opinions, without establishing a conclusive evidence. 7 In the last decade, researchers conducted several studies to explain the relationship between TMDs and orthodontic treatment. 8,9 Despite the use of sophisticated and modern diagnostic tools such as magnetic resonance imaging, and scientific studies with long-term follow-up, it has not yet been possible to eliminate this existing controversy. 10 Although there is no significant evidence supporting the predisposing effect of orthodontic Al-Groosh DH, Abid M, Saleh AK -The relationship between orthodontic treatment and temporomandibular disorders: A dental specialists' perspective treatment on TMDs and occlusion, the treatment is not indicated as a therapeutic measure or a means to decrease the risk of the disorders. 11,12 However, the attention given to signs and symptoms associated with TMDs has modified the clinical management before and during orthodontic treatment. 13 Although the disorder has a normal cycle of events, appearing to spontaneously improve without treatment, the treatment of such a group of disorders involves a multidisciplinary approach with robust protocols. 14,15 A team of oral medicine specialists, surgeons and orthodontist may collaborate to manage these disorder using protocols ranging from nonsurgical medications to surgical interventions.

INTRODUCTION
To the authors' knowledge, the perception of orthodontists, oral surgeons and the oral medicine specialists together was not investigated; therefore, this study was designed to assess the beliefs, despite scientific evidence, of the TMDs team of specialists about the relationship between TMDs and orthodontic treatment, with regard to treatment, prevention and possible etiology. A pilot study was conducted on 15 academics and experienced specialists (five from each discipline), using the same questionnaire, to minimize unclear and ambiguous questions.
Consequently, the questions were reviewed and modified to ensure scientific accuracy.  The sample size was calculated using the following formulae: 17 (1) Required sample size = p (100 - p) z 2 /E 2 (2) True sample = (required sample size x population) (required sample size + population -1) Where 'p' is 50% of a sample; 'z' is the level of confidence, which is equal to 1.96 (for confidence level of 95%), and 'E' is the margin of error = 0.05.
After data acquisition, descriptive statistic represented by tables and histograms was used to analyze the percentages of the respondents' answers. Additionally, chi-square test was done to find an association between the referral status and specialists' experience, and to compare between the different disciplines' belief.

RESULTS
The  10 and oral medicine specialists have more than 10 years' experience ( Table 1)  Al-Groosh DH, Abid M, Saleh AK -The relationship between orthodontic treatment and temporomandibular disorders: A dental specialists' perspective There was a statistically significant association between the time after training program and the referral status of the orthodontists and the oral surgeons (p < 0.001). Less time since the training program was related to more referral status for orthodontists, however, the opposite was true for the oral surgeons, as shown in       Al-Groosh DH, Abid M, Saleh AK -The relationship between orthodontic treatment and temporomandibular disorders: A dental specialists' perspective

DISCUSSION
Although the use of questionnaires is fundamental for knowledge and perceptive research, it may have some limitations, such as poor adhesion of participants, which reduces the number of answers, low response rate and, sometimes inconsistency of the answers. 18 The authors tried to reduce these issues by using the web-based questionnaire, 19 however, online survey may discriminate senior individuals who are not regular 'cyber users', which may, in turn, affect the overall data. This comes in agreement with a previous study reporting that the age of participants may affect their willingness to participate, especially in web-based questionnaire. 20 In this context, the sample size of the current study was in accordance with the calculated sam- Yet, misreporting these questions may be encountered.
The results of the current survey showed that the response rate was higher than in the previous survey conducted on orthodontists. 16 This finding is in accordance with Saleh and Bista,20 who reported that the participation rate was higher in online based surveys, compared to the conventional ones. This could be due to several influencing factors such as survey structure, communication methods, professionalism (target group) and simplicity of the questions. The setup of questions and question-answering process in online based questionnaire made handling the survey questions an easy task. 20 The majority of orthodontists believed that orthodontic treatment had no effect on TMDs symptoms. This is in accordance with the scientific evidence in which most of the previous studies suggested that orthodontic treatment neither prevents nor causes TMDs. 21 Therefore, setting up interdisciplinary clinics, with oral surgeons, oral medicine specialists and orthodontists involved in a coordinated way with different treatment approaches, is recommended. Moreover, continuing program development series is important to embrace the concept of the multidisciplinary team approach and improve the health care service and the quality of life for those patients.

CONCLUSIONS
The majority of orthodontists' beliefs came in accordance with the scientific evidence regarding the lack of relationship between orthodontic treatment and TMDs symptoms, and that orthodontic treatment does not necessarily prevent the onset of TMDs.
This was significantly different from the point of views of other participating health professionals, who believed that orthodontic treatment has implications to TMDs. The study, additionally, showed that there is a statistically significant association between the time after specialists' training program and the referral status. The majority of the oral surgeon tried to treat those patients, unlike the orthodontists and the oral medicine specialists, who seemed to have an interdisciplinary approach attitude.