/home/opencode/cpanel/stomaeduj_hacked/uploads/2018/02/Article_5_2_6.pdf GERODONTOLOGY Original Article COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS Minh Son Nguyen1,2a*, Ülle Voog-Oras1b, Triin Jagomägi1c, Mare Saag1d 1 Institute of Dentistry, Faculty of Medicine, University of Tartu, Raekoja plats 6, 51003 Tartu, Estonia 2 Department of Prosthodontics, Faculty of Stomatology, Danang University of Medical Technology and Pharmacy, 99 Hung Vuong, Danang, Vietnam a DDS, PhD, Head of Department b MD, PhD, Associate Professor c DDS, PhD, Associate Professor d DDS, PhD, Professor, Head of Institute ABSTRACT DOI: 10.25241/stomaeduj.2018.5(2).art.6 Introduction: Temporomandibular disorders (TMD) are a group of disorders that may OPEN ACCESS This is an cause functional limitations. The aim of the study was to compare the differences in dental Open Access article under the CC status, oral behaviour, and mandibular functional limitations between TMD and non-TMD BY-NC 4.0 license. Peer-Reviewed Article elderly people in Vietnam. Methodology: The sample consisted of 146 TMD and 112 non-TMD elderly. The dental and Citation: Nguyen MS, Voog-Oras Ü, Jagomägi T, Saag M. Comparison of dental periodontal status were evaluated with DMFT and CPI indices. The participants self-rated status and oral function in the elderly with frequency of oral behaviour activities (21-item Oral Behaviour Checklist) and mandibular and without temporomandibular disor- ders. Stoma Edu J. 2018;5(2):118-124. functional limitations (20-item Jaw Functional Limitation Scale). Results: The mean number of missing teeth in TMD group was 9.6 ± 8.6, while it was 7.6 ± Academic Editor: Hiroshi Ogawa, DDS, MDSc, PhD, Associate Professor, Niigata 6.4 in non-TMD group (p = 0.036). Gingival bleeding in TMD group was detected at 18.3 ± University, Niigata, Japan 10.2 teeth, which was less than in non-TMD group (21.0 ± 8.7, p = 0.023). The mean number Received: May 22, 2018 of sextants with a 0–3 mm clinical attachment loss was high for non-TMD group (1.4 ± 2.0, Revised: May 28, 2018 Acccepted: June 18, 2018 p = 0.021), while the mean number of excluded sextants was high for TMD group (1.3 ± 1.8, Published: June 20, 2018 p = 0.037). The TMD elderly group reported more frequent instances of “Hold, tighten, or *Corresponding author: Dr. Minh Son tense muscles” than non-TMD group. No significant differences were found in the self-rated Nguyen, DDS, PhD Institute of Dentistry, mandibular functional limitations between the two groups. Faculty of Medicine, University of Tartu 6 Raekoja Plats, Tartu 51003, Estonia. Tel: Conclusion: TMD were associated with missing teeth and periodontal diseases. There was +84983060321, Fax: +372 7319856, e-mail: no association between TMD and mandibular functional limitations. The elderly suffering minhson1883@gmail.com from TMD tended to have increased frequency of holding, tightening, or tensing muscles. Copyright: © 2018 the Editorial Council Keywords: dental caries, elderly, mastication, oral function, temporomandibular disorders. for the Stomatology Edu Journal. 1. Introduction factors of ageing contribute to the increasing signs Temporomandibular disorders (TMD) are the group of of TMD, including limited mouth opening, muscular disorders affecting the temporomandibular joint and tenderness, and TMJ sounds, all of which can affect structure-related joint. The prevalence of TMD in the on masticatory performance. Ohrbach et al. [13] and older adult population varies from 33% to 56.6% [1,2]. Markiewicz et al. [14] initially developed the Diagnostic TMD often cause orofacial pain, limit the function of Criteria for Temporomandibular Disorders (DC/TMD) the masticatory system, and also impact on quality of axis II to determine the presence of parafunctional life [3]. and functional limitations of the masticatory system. Multiple factors contribute to the TMD process. However, norms have not yet been established for those Dentition is a part of the masticatory system, and instruments, particularly in the older adult population. the global burden of dental caries and periodontal Regardless of whether or not elderly with TMD have diseases can increase the risk of TMD in the older adult more limited oral function compared to those free population [4]. Our previous studies indicate that more from TMD, because many factors such as dental status, than 50% suffer from TMD [2]. Studies on TMD at the neuromuscular changes, and psychosocial factors can age over 60 years old also reported that 17.5–52.2% influence oral function of this age group. of patients had less than 20 teeth, and 10.9–34.3% Therefore, the aim of the study was to compare the were edentulousness [5–7]. After dental pain, TMD is differences in dental status, oral behaviours, and the most the common cause of pain in the orofacial functional limitations of the masticatory system area; therefore, dental diseases and TMD may share between the TMD and non-TMD elderly people. symptoms and clinical comorbidities. The parafunctional habits of bruxism and teeth clenching have been regarded as risk factors for 2. Materials and methods TMD pain [8–10]. TMD patients are also limited in The total sample comprised 258 volunteer participants their daily activities and have increased frequency aged 65–74 years in Danang City, Vietnam. Based on of oral parafunction [11,12]. The cumulative risk clinical examination of TMD according to DC/TMD axis 118 Stoma Edu J. 2018;5(2): 118-124 http://www.stomaeduj.com COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS I [15], our previous study revealed that 56.6% (n = 146) Original Article Table 1. Comparisons of dental caries status between the TMD and non- of the total sample were diagnosed with TMD (TMD TMD elderly participants. group) and 43.4% (n = 112) were free of TMD (non- TMD Non-TMD TMD group) [2]. In the current study, the participants of Variable p-value (n = 146) (n = 112) both groups were invited to examine dental status and Sound teeth evaluate oral function. Written informed consent that explained oral Number of subjects 131 110 examination procedures was obtained from each Percent % 89.7 98.2 0.009*a participant. This study was registered and approved by Mean number of teeth 15.5 ± 9.4 17.6 ± 8.7 0.070 the Human Research Ethics Committee of the Danang Decayed teeth University of Medical Technology and Pharmacy (No. 523/CN-DHKTYDDN 2014) and was performed Number of subjects 120 108 in accordance with the World Medical Association’s Percent % 82.2 96.4 < 0.001*a Helsinki Declaration. Mean number of teeth 6.3 ± 5.6 6.5 ± 5.4 0.684 Missing teeth 2.1. Clinical examination of dental status The dental status of each participant was examined Number of subjects 134 106 by using the Decayed Missing Filled Teeth (DMFT) Percent % 91.8 94.6 0.463 index. The primary caries appeared on the crown or Mean number of teeth 9.6 ± 8.6 7.6 ± 6.4 0.036*b root of a tooth, or secondary carious lesions nest to the Filled teeth restoration was considered a decayed tooth (DT). A missing tooth (MT) was a tooth lost due to caries or any Number of subjects 12 10 other reason. A filled tooth (FT) was considered with Percent % 8.3 8.9 1.000 at least one filled surface and without any caries. The Mean number of teeth 0.2 ± 0.9 0.3 ± 1.1 0.710 DMFT score was the sum of the DT, MT, and FT scores Caries experience and ranged from 0 to 32. Number of subjects 143 111 2.2. Clinical examination of periodontal status Percent % 97.9 99.1 0.635 Periodontal status was evaluated using the modified Mean DMFT 16.0 ± 9.5 14.4 ± 8.7 0.152 Community Periodontal Index (CPI). The modified CPI records two indicators of periodontal status: gingival a Fisher’s exact test, b Student t-test, * statistically significant bleeding and periodontal pockets. All teeth present TMD: Temporomandibular disorders, DMFT: Decayed Missing Filled Teeth were probed (6 sites per tooth) to record any presence of bleeding on probing and periodontal pocket depth (JFLS-20) [13] and the frequency of parafunctional (PPD). PPD was scored as follows: score 0 (a PPD of behaviours based on the 21-item Oral Behaviour 0-3mm, no pocket), score 1 (a PPD of 4–5mm, shallow Checklist (OBC-21) [14]. pocket), and score 2 (a PPD of ≥ 6mm, deep pocket). JFLS-20 assesses the limitation of mastication (6 items), mandibular mobility (4 items), verbal and emotional 2.3. Clinical examination of clinical attachment loss expression communication items (8 items), swallowing, (CAL) and yawning. Each item was scored on a scale of 0–10 CAL estimates accumulated lifetime destruction of the points (10 points = the most limited mandibular periodontal attachment. CAL was measured from the function). cementoenamel junction to gingival sulcus or pocket at OBC-21 determines the frequency of oral parafunctional 6 sites per index tooth of each sextant. The CAL severity activities during sleep and waking hours. Each item was was recorded based on the highest CAL score of the scored from 0 (never) to 4 (all the time). In the current index tooth as follows: score 0 (CAL 0–3 mm), score 1 study, each item on the JFLS-20 and OBC-21 surveys (CAL 4–5 mm), score 2 (CAL ≥ 6 mm). The sextant was was categorised as No (score = 0) and Yes (score ≥ 1). excluded if there were less than two teeth present. The data was analysed using Version 17.0 of the The first author conducted procedure of dental and Statistical Package for Social Sciences software (SPSS periodontal examination according to the WHO’s Oral Inc., Chicago, Ill., USA). The comparisons of dental Health Survey guidelines (2013). A pilot study of a status, the frequency of parafunctional behaviours, group of 25 elderly people was performed to calibrate and functional limitations of the masticatory system the examiner before the study was carried out. Ten between the two groups was performed using Chi- percent of the participants were re-examined after square test and Student’s t-test. A confidence level of three days to test the reliability of the examination 95% and a two-sided p-value of < 0.05 were used to procedure. The calculated Kappa-values were above reveal significant differences. 0.85, indicating a high degree of intra-examiner and inter-examination reliability. 3. Results 2.4. Evaluation of oral function Prevalence of DMFT was 97.9% in the TMD group All participants were interviewed face-to-face on the and 99.1% in the non-TMD group (p = 0.635). There functional limitations of their masticatory system were significant differences in prevalence between based on the 20-item Jaw Functional Limitation Scale the TMD and the non-TMD groups in terms of sound Stomatology Edu Journal 119 COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS Original Article Table 2. Comparisons of periodontal status between the TMD and non- TMD elderly. Table 3. Comparisons of functional limitations of masticatory system be- tween the TMD and non-TMD elderly. TMD Non-TMD TMD Non-TMD Variable p-value (n = 146) (n = 112) p- (n = 146) (n = 112) Functional limitation valuea Gingival bleeding No. % No. % Chew tough food 120 82.2 85 75.9 0.215 Number of 135 (92.5) 110 (98.2) 0.467 participants (%) Chew hard bread 97 66.4 63 56.3 0.095 Mean number of 18.3 ± 10.2 21.0 ± 8.7 0.023*c Chew chicken 101 69.2 72 64.3 0.407 teeth Chew crackers 62 42.5 46 41.1 0.822 Mastication Prevalence of participants having highest score of PPD Chew soft food 35 24.0 27 24.1 0.980 PPD 0–3 mm 15 (10.7) 15 (13.4) 0.514 Eat soft food requiring no 17 11.6 15 13.4 0.673 chewing PPD 4–5 mm 46 (32.9) 50 (44.6) 0.056 Number of limitation PPD ≥ 6 mm 78 (55.7) 47 (42.0) 0.030*a 3.0 ± 1.9 2.8 ± 2.1 0.400 items (maximum = 6)b Mean number of teeth present with PPD Mean score of each item 2.55 (0.17) 2.26 (0.19) 0.264 PPD 0 –3 mm 12.3 ± 10.2 14.4 ± 9.7 0.085 (SE)b Open wide enough to bite PPD 4–5 mm 7.3 ± 7.9 8.3 ± 8.1 0.342 26 17.8 18 16.1 0.713 from a whole apple PPD ≥ 6 mm 1.0 ± 3.6 0.6 ± 1.7 0.210 Open wide enough to bite 34 23.3 26 23.2 0.989 Mandibular mobility Prevalence of participants having highest score of CAL into a sandwich CAL 0–3 mm 2 (1.4) 12 (10.7) 0.001*b Open wide enough to talk 27 18.5 21 18.8 0.958 CAL 4–5 mm 38 (26.0) 42 (37.5) 0.048*a Open wide enough to 26 17.8 19 17.0 0.859 drink from a cup CAL ≥ 6 mm 45 (30.8) 25 (22.3) 0.128 Number of limitation 0.8 ± 1.5 0.8 ± 1.4 0.896 Excluded sextants 61 (41.8) 33 (29.5) 0.042*a items (maximum = 4)b Mean number of sextants with CAL and excluded sextants Mean score of each item 0.49 (0.09) 0.43 (0.08) 0.659 (SE)b CAL 0–3 mm 0.9 ± 1.4 1.5 ± 2.0 0.021*c Talk 11 7.5 11 9.8 0.514 CAL 4–5 mm 2.4 ± 2.0 2.7 ± 2.2 0.184 Sing 25 17.1 19 17.0 0.973 Verbal and emotional expression CAL ≥ 6 mm 1.5 ± 1.7 1.0 ± 1.7 0.100 Putting on a happy face 12 8.2 11 9.8 0.654 Excluded sextants 1.2 ± 1.8 0.8 ± 1.4 0.037*c Putting on an angry face 12 8.2 12 10.7 0.494 a Chi-square test, b Fisher’s exact test, Student’s to-test, * c statistically significant. Frown 15 10.3 13 11.6 0.733 PPD: Periodontal pocket depth; CAL: Clinical attachment loss. Kiss 14 9.6 10 8.9 0.856 Smile 23 15.8 17 15.2 0.899 teeth (89.7% and 98.2%, p = 0.009) and decayed teeth (82.2% and 96.4%, p < 0.001). The number of missing Laugh 15 10.3 14 12.5 0.575 teeth was statistically higher in the TMD group (9.6 ± Number of limitation ± 2.1 1.0 ± 2.2 0.752 items (maximum = 8)b 8.6 teeth) than in the non-TMD group (7.6 ± 6.4, p = 0.036, Table 1). Mean number of each 0.23 (0.05) 0.21 (0.05) 0.774 item (SE)b Regarding periodontal status, gingival bleeding was detected at 18.3 ± 10.2 teeth in the TMD group, which Swallow 19 13.0 14 12.5 0.903 was lower than 21.0 ± 8.7 teeth in the non-TMD group Yawn 22 15.1 17 15.2 0.980 (p = 0.023). The prevalence of older adults with PPD Number of limitation 4.9 ± 4.9 4.7 ± 5.4 0.815 ≥ 6 mm was higher in the TMD group (55.7%) than items in JFLS-20b in the non-TMD group (42%, p = 0.030). Concerning Total score of JFLS-20 19.8 ± 18.6 17.6 ± 17.6 0.348 clinical attachment loss, occurrences of CAL 4–5 mm ± SDb was 37.5% for the non-TMD group and 26.0% for the a Chi-square test, Student’s t-test. TMD: Temporomandibular b disorders, SE: standard error, JFLS-20: 20-item Jaw Functional TMD group (p = 0.048); whereas, a high prevalence of Limitation Scale. excluded sextants was significantly related to the TMD group (41.8%, p = 0.042). The mean number of sextants of the masticatory items was 2.55 (0.17) for the TMD with CAL 0–3 mm was 0.9 ± 1.4 in the non-TMD group, group, compared to 2.26 (0.19) for the non-TMD which was statistically lower than 1.5 ± 2.0 sextants group (p = 0.260). The prevalence of limitations of of the non-TMD group (p = 0.021); however, the TMD mandibular mobility ranged from 17.8% to 23.3% in group had more excluded sextants (1.3 ± 1.8) than the the TMD group, which were similar with the variation non-TMD group (0.7 ± 1.4, p = 0.037). of 16.1% to 23.2% in the non-TMD group (p > 0.05). Comparing the functional limitations of mastication There were no significant differences between the two revealed no differences between the TMD and non- groups regarding limitations of verbal and emotional TMD group. Most participants in the TMD elderly expression. The total score of JFLS-20 was 19.8 ± 18.6 in group had masticatory limitations related to chewing the TMD group and 17.6 ± 17.6 in the non-TMD group tough food (82.2%), followed by chewing chicken (p = 0.348, Table 3). (69.2%), and chewing hard bread (66.4%); the results There were significant differences in the prevalence for the non-TMD group were 75.9%, 64.3%, and 56.3%, of parafunctional activities between the TMD and respectively. The mean score (standard error) of each non-TMD groups in terms of “Hold, tighten, or tense 120 Stoma Edu J. 2018;5(2): 118-124 http://www.stomaeduj.com COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS muscles without clenching” (7.5% and 1.8%, p = Original Article Table 4. Comparisons of parafunctional behaviours between the TMD 0.036) and “Eating between meals that food requires and non-TMD elderly. chewing” (43.2% and 57.1%, p = 0.026). The TMD group TMD Non-TMD also tended to have more prevalent parafunctions Parafunctional habit (n = 146) (n = 112) p- of “Press tongue forcibly against teeth” and “Place valuea n % n % tongue between teeth” (p = 0.067 and p = 0.079, Sleep activities respectively) compared to the non-TMD group. No significant differences were found in the mean number Clench or grind teeth when 16 11.0 9 8.0 0.431 asleep of parafunctional items between the two groups (p = 0.928, Table 4). Sleep in a position that puts 57 39.0 44 39.3 0.968 pressure on the jaw Waking activities 4. Discussion Grind teeth together during 9 6.2 7 6.3 0.977 waking hours The current study highlighted a different dental status between the TMD elderly and non-TMD elderly groups. Clench teeth together during 12 8.2 10 8.9 0.840 waking hours Our TMD elderly group lost an average of 9.6 ± 8.6 teeth and were higher than the non-TMD group; in other Press, touch, or hold teeth together other than while 28 19.2 24 21.4 0.655 words, our study was in accordance with previous eating findings indicating that there was association of TMD Hold, tighten, or tense muscles with missing teeth [16–18]. When individuals lose without clenching 11 7.5 2 1.8 0.036* many teeth, their chewing pattern can be changed and Hold or put jaw forward or to have impact on masticatory performance. Numerous the side 17 11.6 11 9.8 0.641 studies indicated that chronic unilateral chewing Press tongue forcibly against increases the risk of TMD [18,19]. In addition, tooth 31 21.2 14 12.5 0.067 teeth loss causes social limitations, psychological disorders, Place tongue between teeth 32 21.9 15 13.4 0.079 and reduces the quality of life, all of which have been Bite, chew, or play with your regarded as factors contributing to TMD. tongue, cheeks or lips 27 18.5 19 17.0 0.750 The main finding of our study was that periodontal Hold jaw in rigid or tense diseases have influence on TMD. PPD ≥ 4 mm indicates position 17 11.6 10 8.9 0.480 periodontal tissue destruction due to inflammation, Hold between the teeth or bite while the CAL measurement estimates lifetime 8 5.5 8 7.1 0.583 objects accumulated destruction of the periodontal attachment. Use chewing gum 20 13.7 19 17.0 0.468 These measures permit comparisons the severity of Play musical instrument that periodontal diseases between population groups. Our involves use of mouth or jaw 4 2.7 1 0.9 0.392 finding indicated that PPD and CAL were worse in the Lean with your hand on the jaw 50 34.2 36 32.1 0.722 TMD group than in the non-TMD group. More than Chew food on one side only 82 56.2 63 56.3 0.989 half of the TMD group had PPD ≥ 6 mm and over 70% of those had the CAL ≥ 6 mm and excluded sextants. Eating between meals that food 63 43.2 64 57.1 0.026* requires chewing All these numbers were comparatively high compared Sustained talking 67 45.9 49 43.8 0.732 to 42% and 51.8%, respectively, in the non-TMD group. In the elderly population, periodontal diseases are the Singing 33 22.6 34 30.4 0.159 most frequent cause of tooth loss; therefore, TMD was Yawning 48 32.9 43 38.4 0.353 significantly associated with both periodontal diseases Hold telephone between your 10 6.8 6 5.4 0.622 and tooth loss in the current study. head and shoulders Gingival bleeding does not affect single tooth but Number of parafunctional habits can affect many remaining teeth in the mouth, but 0 15 10.3 12 10.7 the TMD group had more missing teeth than the non- 1–4 72 49.3 54 48.2 TMD. Therefore, the number of teeth with gingival 0.921 bleeding was observed less in the TMD group in our 5–8 36 24.7 31 27.7 study. Periodontal inflammation has been considered a ≥9 23 15.8 15 13.4 potential risk factor for other diseases. Proinflammatory Mean number of 4.40 ± 3.71 4.36 ± 3.23 0.928 cytokines enhance the pathogenesis of periodontal parafunctional habits ± SDb diseases. Interleukin (IL-1) and tumour necrosis factor a Chi-square test, Student’s t-test, statistically significant. b * TMD: Temporomandibular disorders, SD: standard deviation. alpha (TNF-α) represent proinflammatory cytokines that stimulate a number of events which occur during Regarding peripheral sensitization, nociceptive infection with periodontal pathogens. Graves et al. afferents in the periodontal ligament could be activated found a widespread presence of IL-1 and TNF in the when periodontal tissues under pressure become connective tissue and loss of alveolar bone along with painful due to bacterial infections. Afferent nerve periodontal inflammation [20]. High levels of IL-1 and fibres carry the impulse to the trigeminal spinal tract TNF-α are a response to the inflammatory process and nucleus and stimulate interneurons. The efferent fibres they might penetrate into the TMJ synovial fluid and of the inhibitory interneurons synapse, which lead to cause bone tissue resorption; therefore, the degree of the elevator muscle reaction, bring the teeth away endogenous cytokine control is important for bone from the noxious stimulus [22,23]. These repetitions tissue destruction in the TMJ structure [21]. might cause masticatory muscle dysfunction. The Stomatology Edu Journal 121 COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS findings of Jeon et al. [19] suggested a positive elderly, including chronic orofacial pain, psychological Original Article correlation between chronic periodontitis and TMD- disorders, and age-related reduction of the motor related muscle pain, while Fabri et al. [24] found that function of masticatory muscles [29–31]. The important there were clinical comorbidities between periodontal finding of the current study was that determining the disease and craniofacial pains. All these studies support JFLS-20 score of older adults might enable us to predict our findings indicating that periodontitis accumulated TMD, as the prevalence of TMD is correlated with an over time might be a risk factor for TMD. increasing JFLS-20 score in the general population [13]. TMD are a group of disorders that disrupt function The limitation of the study was that we only studied or cause parafunction of the masticatory system. the oral function and parafunctional behaviours based Surprisingly, the number of oral parafunctional on self-rated questionnaires. There is a need for more activities was equal across two groups; participants clinical research on this aspect. in both groups had a range of 4–5 parafunctional behaviours. Our study is in accordance with Leketas et al.’s study [25] indicating that the behaviours of “Lean 5. Conclusion with your hand on the jaw”, “Chew food on one side Temporomandibular disorders were associated with only”, and “Sleep in a position that puts pressure on the missing teeth and periodontal diseases. There was no jaw” were the most common in the TMD group. Meulen association between TMD and mandibular functional et al. [26] showed that these parafunctional behaviours limitations among the elderly. The elderly suffering often had higher scores than other parafunctional from TMD tended to have increased frequency of items when evaluating the validity items of OBC-21 holding, tightening, or tensing muscles. in the Dutch population. This could suggest that the frequency of parafunctional behaviours affected TMD. The current study found that 2 out of 21 items of OBC Conflicts of interest were significantly associated with TMD among the The authors declare that they have no conflict of elderly. The TMD group had higher frequency of “Hold, interest. tighten, or tense muscles without clenching”, but a lower frequency of “Eating between meals (i.e., food that requires chewing)” than the non-TMD group. These Author contributions findings could be explained by muscular activity. The MSN searched literature, performed clinical studies, increase in the frequency of tensing muscles heightened data acquisition and statistical analysis, and wrote draft the risk of TMD between 2.9 – 10.8 times [25]. Based on of manuscript. ÜVO, TJ, and MS designed protocol, an electromyography study, Ohrbach et al. found [27] interpreted data, and edited the manuscript. All a high score of masseter muscular activity in subjects authors read and approved the final manuscript. with tense muscles. A high activity of masseter muscle in combination with the neuromuscular change in older age would cause muscular disorders, a subgroup Acknowledgements of TMD. This also explained why the TMD elderly group This study was supported by the Estonian Science had a lower frequency of eating between meals in our Foundation grant ESF 9255, the Estonian Research study because of muscular impairment. Council IUT 20-46, and the Internationalization The current study reported difficulty chewing tough Programme DoRa of the European Social Fund, which is and hard food in most participants, but none indicating carried out by the Foundation Archimedes. The authors that TMD was related to functional limitations of would like to thank the volunteer participants from the mastication; such findings contrast with findings of Hoa Vang, Hai Chau, Thanh Khe, and Cam Le districts Brandini et al. [28]. 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He has been the lecturer of the Danang University of Medical Technology and Pharmacy Vietnam since 2008 and appointed as the Head of the Department of Prosthodontics in 2014. More than ten articles were published in international peer-reviewed journals, four manuscripts have been submitted for publication, and fourteen abstracts were presented at international conferences, all of which are his scientific achievements during the period of the Doctoral curriculum at the University of Tartu, Estonia (2014–2018). His research interest is related to prosthodontics, community dental health, geriatric dentistry, occlusion, orofacial pain, and temporomandibular disorders. Stomatology Edu Journal 123 COMPARISON OF DENTAL STATUS AND ORAL FUNCTION BETWEEN THE ELDERLY WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS Questions Original Article 1. What is true for temporomandibular disorders (TMD)? qa. TMD mainly cause parafunctional behaviors; qb. The most prevalent orofacial pain is from TMD; qc. It only affects temporomandibular joint; qd. TMD signs tend to increase with aging. 2. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) axis II is used to evaluate: qa. Clinical signs of temporomandibular disorders; qb. Quality of life related to temporomandibular disorders; qc. Psychological domains and oral function; qd. The balance of occlusion. 3. Which is not considered as oral parafunction: qa. Limited mouth opening; qb. Bruxism; qc. Clenching; qd. Unilateral chewing habit. 4. Prevalence of edentulousness among TMD population is: qa. 0–5%; qb. 11–35%; qc. 51–70%; qd. Over 80%. https://clinicaldentistry.dentistryconferences.com/ 124 Stoma Edu J. 2018;5(2): 118-124 http://www.stomaeduj.com