tmd is not a life - threatening disease , but the quality of life may be reduced.7 generalized joint hypermobility is a hereditary problem defined by the increase in range of motion in multiple joints , which might affect tmj in some cases that is named tmj hypermobility ( tmjh).3,8 joint range of motion might be affected by numerous factors including : biochemical changes in the structure of collagen and elastin , loss of resistance to traction , laxity , and increase joint mobility.3 winocur et al .
conducted a study about the prevalence of general joint laxity and tmjh among adolescent girls .
they concluded that the prevalence of generalized joint laxity was 43% and tmjh was recognized in 27.3%.8 in another survey , adair and hecht discovered that participants with generalized joint hypermobility may be more likely to demonstrate some signs and symptoms of tmd than ones with normal joint mobility.9 in another view , correlations between dental occlusion and ( tmd ) have been proved , also mandibular resting position can be affected by different factors such as : occlusal interferences , tmd , the position of the head and body of mandible , and emotional tensions , which may lead to bodily adaptations and realignments of tooth and tmj.1,10,11 due to the fact that generalized joint hypermobility and tmjh are reported as risk factors for tmd,12 the aim of this study was to clarify the etiological factors of tmjh and its relations to habitual modalities .
ethics : present article is based on thesis with i d number of udk:616.724 - 08.089.23 ; the survey was executed in medical and surgical department of poltava dental clinic and maxillofacial department of pokb , ukraine ; also a medical consent was filled by each contributors and all procedures were required for treatment plans .
this observational / case - control clinical study was conducted on 69 individuals between the ages of 22 and 42 who had the manifestation of tmjh . any severe systemic disease ( like rheumatoid arteritis ) and un - cooperation were assumed as criteria . after profiling personal information and medical history , the patients were divided into three groups based on their maximum mouth opening ( mmo ) , which was measured by a disposable ruler between upper and lower incisors:9 
 light : 25 patients with mmo of 50 - 55 mm.moderate : 18 patients with mmo between 55 and 65 mm.severe : 26 patients with mmo > 65 mm . 
 
severe : 26 patients with mmo > 65 mm . for subjective observations , patients were asked to fill the prepared questionnaire , with the help of examiner if it was necessary , to reveal following information : 
 discomfort of tmj during mmopain in tmj during mmopain in masticatorstmj clicking or other soundsirradiation of pain in the ear(s ) , temple or neckusual side of chewingusual side of tmj which was lied on during asleepthe first symptoms of tmjh if they were recalled . 
 
discomfort of tmj during mmo pain in tmj during mmo tmj clicking or other sounds irradiation of pain in the ear(s ) , temple or neck usual side of chewing usual side of tmj which was lied on during asleep the first symptoms of tmjh if they were recalled .
then extra oral observation followed as facial asymmetry , condition of the facial musculoskeletal system , functional and morphological changes in the teeth and jaw system and a detailed research of the nature of pathological changes in the tmj , palpation of tmj projection zone , manual assessment of muscle tone , movements of the mandible in the horizontal and vertical planes , malocclusion caused by teeth positions , analysis of dynamic occlusion in order to evaluate the performance of jaw movements , the amount of lateral movements of the mandible , passive movement of the mandible , passive compression by means of bilaminar zone adaptation , and dynamic compression for evaluation of ligamentous apparatus , the joint capsule and articular surfaces . to assess masticatory system specially temporal and medial pterygoid muscles ,
auscultation was performed using stethoscope which was tightly applied to the joint , but without pressure .
it was necessary to listen to the noise in the joint space or separate quadrants of the joints .
at the end , consultations with orthopedic , dentists , rheumatologist , and neurologist were performed if necessary .
all the data subjected to chi - square test by using spss software version 22 at a significant level of 0.05 .
this study was conducted on 69 patients ( 54 women and 15 men ) , at the age from 22 to 42 years old .
the largest number of patients with tmjh was at the age of 31 - 42 years old ( 70.99% ) , while 37.67% were at the age from 26 to 35 years old .
furthermore , the number of women was three times more ( 78.2% ) than men .
distribution of subjective and objective criteria ( % ) of all the groups alongside with statistical comparisons ( p value ) .
medical history of patients revealed the presence of familial tmj diseases in one case of a moderate group .
eight patients did not ask for medical treatments , 4 people referred to a dentist , 2 people to otorhinolaryngologist , and 2 others to a neurologist . the main treatment was to assign non - narcotic analgesics and physiotherapy ,
however , the effects were short - term in 11 people and without success for 5 patients .
based on the results of this study , tmjh was more common in women ( 74.2% ) , which is in agreement with other studies.13 - 15 pain appears to have significant relationship with impairment of oral health related to the quality of life .
pain is induced when an imbalance occurs between the amount of stimuli and the efficacy of modulation mechanisms.7,16,17 as the result showed , the light group had significant differences with other groups in the discomfort of tmj and tmj sound . in a study with the aim of classifying symptomatic patients diagnosed with tmd into homogenous groups based on their clinical presentation , pimenta e silva machado et al . claimed that localized masticatory muscle pain is recognized as the most common complaint in tmd patients.18 similar results were found in present study in which sever group manifested highest percentage of masticatory pains , significantly . in that study ,
recently the most popular theories about etiology of tmds are based on the biopsychosocial pattern , which is a combination of biological , psychological , and social factors .
quality and pattern of sleeping and stress showed correlation with tmds.7,19 sleeping on affected tmj was the highest in the light group .
perhaps , the higher level of pain in moderate and sever groups make some uncomfortable sensation during sleeping on the affected tmj .
winocur et al . found a positive correlation between tmjh and mmo.8 this result is in accordance with pasinato et al .
study about evaluating clinical and psychosocial aspects in tmd patients with or without generalized joint hypermobility , too.3 however , westling and helkimo did not found a significant relationship between mmo and peripheral joint mobility.20 furthermore , hirsch et al . concluded that patients with hypermobility had a lower risk of having limited mmo.21 present result hypothesis the correlation between pain in masticatory muscles and higher mmo
concluded that facial asymmetry due to mandibular lateral displacement is a relatively common problem in tmds.22 however , haghigaht et al . reported that condylar distance was higher in posterior and superior borders in tmjh.23 that might explain the differences .
ogtcen - toller believed that clicking and crepitation may be considered as signs of abnormal joint disorder24 and the present result confirmed it too . in the present study , a few of individuals sought for the tmjh treatments .
although hypermobility is relatively common in the general population , but reports about musculoskeletal complaints are infrequent . as most symptoms are mild and self - limiting , so patients may not search for medical attention.25
regarding to the limitations of this study like : low sample size , uneven sample size in groups , limitation of time and etc . , it can be concluded that pain in tmj would have a correlation with mmo .
 background : joint range of motion might affected by some factors like laxity and increase joint mobility . generalized joint hypermobility and temporomandibular joint hypermobility ( tmjh ) are reported as risk factors for temporomandibular disorders . 
 the aim of this study was to survey the etiological factors of tmjh and its relations to habitual status.materials and methods : in this cross - sectional descriptive study , 69 patients with tmjh were involved . after profiling personal information and medical history , 
 the patients were divided into three groups based on their maximum mouth opening ( mmo ) as follow:(light ) mmo of 50 - 55 mm , ( moderate ) : mmo between 55 and 65 mm , ( severe ) mmo > 65 mm . for subjective observations , 
 patients were asked to fill the prepared questionnaire . 
 the objective evaluations conducted by a specialist . finally , all the data subjected chi - square test by using spss software version 22 at a significant level of 0.05.results:tmjh was more common in women ( 74.2% ) . 
 the light group had significant differences with other groups in the discomfort of tmj and tmj sound ( p < 0.05 ) . 
 furthermore , sever group manifested highest percentage of masticatory pains , significantly ( p < 0.05).conclusion : it can be concluded that pain in tmj would have a correlation with mmo . 
Introduction
Materials and Methods
Results
Discussion
Conclusion