Tempromandibular Disorders and Perceived Emotional Stress Among Medical and Dental Students Studying in a Private Medical Institution in Kathmandu, Nepal

Introduction: Tempromandibular disorder (TMD) is a collection of complex signs and symptoms that typically involves the tempromandibular joint (TMJ) and masticatory muscles. Multifactorial etiologies of TMD include occlusal disharmony, oral habits, dysfunction of masticatory muscles and adjacent structures, emotional stress and extrinsic and intrinsic changes on TMJ structure. Stress has been inflicted as one of the major etiological factor for developing TMD. Materials and Methods: An observational cross sectional study was conducted among the medical and dental undergraduate students and interns studying in Nepal Medical College and Teaching Hospital, Kathmandu, Nepal from January 2018 to February 2018. Fonseca Amnestic Index (FAI) was used to evaluate and to characterize the TMD signs and symptoms. The stress factor was assessed by Cohen Perceived Stress Scale (CPSS-10) which is a self report measure of stress level which consist of 10 questionnaires in which the subjects responds on how much they suffer from the listed symptoms. Data was analyzed using the Statistical Package of Social Sciences (SPSS) Version 16.0. Association of different variables were tested, with Chi square test, with value less than 0.05 as statistically significant. Results: A total of 487 students had participated. Among them 32.4%were male and67.6%were female. Among the participants, 44.6%were from dental school (BDS) and 55.4%were from medical school (MBBS). The age group of the participants was 17 to 27 years. Prevalence of TMD was 50.3% in the study participants. Among the participants with TMD, 81.2% had mild TMD, 17.2% had moderate TMD and 1.6% had severe TMD. Out of the total participants 16.4% had low stress, 76.6% had moderate stress and 7% had high stress.This study showed statistically significant association between stress factor and tempromandibular disease (p <0.001). Conclusion: Higher rate of TMD and level of stress has become common in medical and dental college students. Identifying the TMD at the early age can control or at least minimize its long term effects. Moreover,identifying the stress factor highlights the importance of providing support programs and implementing preventive measures to help students.


Introduction
T empromandibular disorder (TMD) is a collection of complex signs and symptoms that typically involves the tempromandibular joint (TMJ) and masticatory muscles. 1 The presenting features of TMD includes pain in the pre-auricular area, TMJ or masticatory muscles, restriction,limitation or deviation in mandibular motions, clicking in the TMJ during mandibular movements and fatigue of the head and neck muscles which are not associated to any growth and development disorders, systemic diseases and trauma. [1][2][3][4][5] Multifactorial etiologies ofTMD include occlusal disharmony, oral habits, dysfunction of masticatory muscles and adjacent structures, emotional stress and extrinsic and intrinsic changes on TMJ structure. [1][2][3][4][5][9][10][11][12][13][14][15][16] Studies have shown a high prevalence (60-70%) of TMD in general populations showing at least one sign of the disorder in a lifetime but only 5% of them seek for the treatment. 1,5 Studies among the undergraduate university students have shown 40-70% prevalence of TMD. [4][5][6] Studies in the Indian subcontinent university students have shown a prevalence of 45-65% of TMD. 12,13 Study on preclinical dental students of one of the dental colleges in Nepal has shown a prevalence of 38.66%. 14 Due to variability of complaints, TMD is diagnosed by associating signs and symptoms. Fonseca Amnestic Index (FAI) developed from Helkimo's index, is used to evaluate and to characterize the TMD signs and symptoms in a short period of time, with low cost, easy understanding and having no influence of the evaluator in the answers of the question. 1,2,4,[6][7][8] Several studies have reported the relationship between TMDs and stress affects parafuctional activities by the limbic system that influences muscle activity. Millan has reported the molecules involved in the mechanism of stress are same associated with the pain resulting in impaired sensation of pain in stressful situations. 11 De Leuw et al is equivocal that muscle dysfunction and pain are often caused by stress induced muscle hyperactivity. 11 Cohen's perceived stress scale (CPSS 10) is a brief measure of stress administered via selfreport in which the subjects responds on how much they suffer from the listed symptoms in Likert scale ranging from 0 (never ) to 4 (very often). Studies have proved the validity and consistency of CPSS as a measure of stress. [17][18][19] TMD has been reported with high prevalence in the population with large number of adolescents being affected with it. Stress has been inflicted as one of the major etiological factor for developing TMD. As in case of medical and dental students, high prevalence of stress has been reported. In the management of TMD unless the etiological factors are eliminated there will be little or no improvement with greater chance of recurrence with greater degenerative changes in TMJ. But it is always difficult to eliminate the stress from daily routine. Thus by identifying the TMD at the early age we can control or at least minimize its long term effects. Moreover identifying the stress factor highlights the importance of providing support programs and implementing preventive measures to help students, particularly those who are most susceptible to higher levels of these psychological conditions.

Materials and Methods
An observational cross sectional study was conducted among the medical and dental undergraduate students and interns studying in Nepal Medical College and Teaching Hospital, Kathmandu, Nepal from January 2018 to June 2019. All the participants were explained about the objective of study and the questionnaires for the study.
Participants previously diagnosed with orofacial pain and undergoing treatment for TMD, participants with any local and/or systemic diseases associated to TMJ or with somatognathic system impairment and those unwilling to participate were not included for the study. Participants who gave written consent were included in the study. Confidentiality of all the participants were maintained The stress factor was assessed by Cohen Perceived Stress Scale (CPSS-10) which is a self report measure of stress level which consist of 10 questionnaires in which the subjects responds on how much they suffer from the listed symptoms in Likert scale ranging from 0 (never) to 4 (very often). The values of the answers were given in the Likert sacale of 0 (never), 1 (almost never), 2 (sometimes), 3 (fairly often) and 4(very often). Total score is 40 with the range of 0-13(low stress), 14-26 (moderate stress) and 27-40 (high perceived stress).
Data was analyzed using the Statistical Package of Social Sciences (SPSS) Version 16.0.
Association of different variables were tested with Chi square test with value less than 0.05 statistically significant.Ehical cleaarence for this study was approved by Nepal Medical College -Intitution Review Committee (NMC-IRC). 6.
In the last month, how often have you found that you could not cope with all the things you had to?

7.
In the last month, how often have you been able to control irritations in your life? * 8.
In the last month, how often have you felt that you were on top of things? * 9.
In the last month, how often have you been angered because of things that happened that were outside of your control? 10.
In the last month, how often have you felt that difficulties were piling up so high that you could not overcome them? Association of students of MBBS and BDS and level of TMD was notstatistically significant (p=0.07).

Results
Similarly association of BDS and MBBS students and different level of stress showed statistically significant association between the variables(p<0.001).
Among 80 participants with low stress level, TMD was present in 26 whereas 54 had no signs of TMD. Those 373 with moderate stress level 195 had TMD and 178 did not have TMD.
Similarly, 34 with high stress level, 24 had TMD and 10 did not have any TMD. This study showed statistically significant association between stress factor and tempromandibular disease (p <0.001) Journal of Nepalese Prosthodontic Society (JNPS)    Results of present study showed that higher prevalence of moderate stress level in both BDS (77.9%) and MBBS(75.6%) students. This is significantly more than the study carried by Kharel et al where he studied 375 medical and dental students in Nepal using the Cohen PSS and found the prevalence of stress was 40.34% in medical students and 34.1% in dental students 19 .High stress level was found more in BDS students(12%) than MBBS students (3%) which is also in contrast to the study by Kharel et al where high stress was more in MBBS students. Moderate and high stress levels were more common for females among both BDS and MBBS students.
This study showed statistically significant relationship between stress factor and tempromandibulardisorder (p <0.001) which is equivocal with other studies. Harris and Finehave shown a significant relation between TMD and anxiety with 50-75% of TMD patient have stressful life prior to onset of their symptoms. 3 Riffel et al have shown a strong correlation between TMD and stress in university students. 6 Augusto et al have also reported 71.9 % the university students with associated TMD had high scale of perceived stress scale. 10 Majumder et al has shown that 206 of 300 (66.2%) medical and dental students with TMD also had signs of anxiety and depression (p<0.001). 12