therefore , a healthy dentist is 
 particularly important for a successful dental practice as well as the well - being of 
 patients2 . despite numerous technical advances of recent years ,
there is increasing evidence that 
 dental professionals are still predisposed to a number of occupational hazards .
these 
 include exposure to infections , eye injuries , vibration , percutaneous exposure incidents , 
 exposure to radiation , dental materials , noise , psychological conditions and musculoskeletal 
 disorders2 , 4 , 
 5 .
it is well known that musculoskeletal diseases ( msds ) are very frequent in the present 
 adult population and have an enormous and growing impact worldwide6,7,8 . in the czech republic
they represent the second most common cause 
 of sick leave after upper respiratory tract diseases9 .
one of the important factors influencing the health status of 
 people is their occupation . as far as dentists are concerned
, many studies have shown that 
 msds represent one of the greatest problems of dental professionals3,4,5 , 10,11,12,13,14,15 .
the one - year period prevalence of musculoskeletal symptoms among 
 dentists ranged from 50 to 93%3 , 4 , 6 , 10,11,12,13,14,15,16,17,18,19 , but some 
 workers reported the one - year prevalence to be 100%20 , 21 .
this , in turn , has an 
 impact on their productivity and ultimately reduces their quality of life1 .
msds contribute significantly to sick 
 leave , reduced productivity and quitting the profession6 , 22 .
the most common regions of pain in dentists are the neck , back and 
 shoulders4 , 6 .
these disorders are due to 
 excessive , long - term unilateral stress on muscles , tendons , joints and nerves24,25,26 .
they are associated with the specific 
 work load in dentistry with its adverse static positions , high demands on vision , precision , 
 fine manipulative hand movements , work with vibrating tools and work with unsupported 
 elevated arms25,26,27,28 .
the load rate is multiplied by age and is also influenced by 
 genetic predisposition25 , 26 .
other very important aspects are the psychological 
 demands on work and stress11 , 13 .
recommendations on how to decrease msds are often only partially implemented 
 even by the relatively motivated group of dentists6 , 
 27 , 29 .
the main reasons that make these changes difficult include 
 financial aspects and changing old working habits6 .
studies related to the msds among the dental profession have already been published in many 
 countries but none have been conducted in the czech republic so far .
the aim of our study is 
 to describe the occurrence of the most common complaints related to msds in czech dentists 
 and to assess the risk factors affecting them .
a cross - sectional study was conducted among czech dentists during the period from november 
 2010 to september 2011 .
the questions were partly designed based on the standardised nordic questionnaire30 ; additional issues concerning specific 
 circumstances of the czech dental population were added by the authors .
the questionnaire 
 was designed to evaluate dentists physical health related to musculoskeletal disorders 
 during the past 12 months , their self - reported general health and their individual working 
 environment and work habits .
the dentists were asked about 12 most common health problems 
 related to msds that occur in dentistry  i.e. pain in the cervical , thoracic and lumbar 
 spine area ; pain in the shoulders , elbow , and wrist ; tingling fingers ; pain in the hip and 
 knee ; headaches ; varicose veins ; and carpal tunnel syndrome .
the intensity of health 
 problems was assessed on a scale of 0 to 3 in which 0 meant no difficulties , 1 mild , 2 
 moderate and 3 major problems .
the four most common complaints were analysed in detail and 
 the results are presented in this paper .
the questionnaire was pilot tested by the authors among 20 dentists selected from the 
 employees of the department of dentistry ( charles university , faculty of medicine in hradec 
 kralove , and university hospital hradec kralove ) and general dental practitioners from the 
 region hradec kralove .
questionnaires were distributed to a total of 800 dentists during their professional 
 educational events organized by the czech dental chamber that took part in various places 
 throughout the czech republic .
the 
 purpose of the survey was explained and instructions on how to fill in the questionnaire 
 were given .
the vast majority of the completed questionnaires were returned on site during 
 the course of the event , some of them were returned by mail at the expense of the 
 respondents .
the ethics committee of the university hospital hradec kralove has approved the 
 study proposal ( reference number 201 306 s03p ) .
statistical analysis was performed using a statistical program ncss 2007 ( ncss , llc . , 

kaysville , ut , usa ) with data analysed using descriptive statistics and the  
 test of independence in the contingency tables and analytical methods .
logistic regression 
 analysis was performed to evaluate the influence of the followed factors on the occurrence 
 of musculoskeletal complaints .
prevalence odds ratios with 95% confidence intervals were 
 calculated as measure of association . for the initial selection of potential risk factors 
 for musculoskeletal complaints , univariate logistic regression analysis was used with 
 significance level of p<0.05 .
subsequently , all independent variables 
 that showed significant associations were included in the multivariate logistic regression 
 model .
the important confounders ( age and gender ) were always included in each model , 
 regardless of their significance .
a total of 800 questionnaires were distributed to the dentists , from which 581 were 
 returned , which achieved a response rate of 72.6% . out of all respondents who participated 
 in our study ,
out of those , 161 were men ( 28% ) 
 and 414 were women ( 71% ) .
the average age of respondents was 46.4  yr ( sd=13 ) , ranging from 
 24 to 77  yr .
their mean dentistry career length was 21.5  yr ( sd=13.3 ) , ranging from 1 to 
 53  yr .
the majority of them ( 93.4% ) worked as general dental practitioners ( n=535 ) and 6.6% 
 worked as specialists ( n=38 ) , of which 5.7% were orthodontists ( n=33 ) and 0.9% maxillofacial 
 surgeons ( n=5 ) .
a total of 96.9% ( n=563 ) of respondents reported suffering from at least one kind of 
 musculoskeletal problem listed regardless of its intensity in the past 12 months .
the 
 remaining 18 dentists ( 3.1% ) did not report any health problems . in terms of intensity , 
 66.3% of respondents ( n=381 ) rated their difficulties as moderate or major and 33.7% ( n=194 ) 
 of dentists experienced problems of only mild intensity or no difficulties at all .
a statistically significant correlation with the occurrence of musculoskeletal complaints 
 of moderate and major intensity was demonstrated in our group for the following factors : 
 gender , age , running a private practice , a history of serious disease in or injury to the 
 musculoskeletal system , a working time over 40  h per week , subjective assessment of their 
 general health and the perception of work as psychologically demanding . a statistically 
 significant number of dentists who had experienced musculoskeletal complaints of moderate or 
 major intensity used exercise as therapy , self - medicated and sought out the help of a 
 specialist more often than those with mild or no difficulties .
they also rated more often 
 that they had to decrease their workload both in the past year and in the past month . on the contrary ,
a statistically significant association was not demonstrated for several 
 other variables with reference to the dentists surveyed : the specialization of the dentists , 
 the occurrence of msds in blood relatives , the occurrence of musculoskeletal congenital 
 defects , regular participation in sport activities , smoking during working hours , working 
 time less than 40  h per week , or whether they favored the right or left hand when 
 working .
detailed analysis concerning descriptive data and statistically significant correlation 
 between the occurrence of musculoskeletal complaints of medium and major intensity and the 
 risk factors are described elsewhere31 . 
 in this paper
we concentrate more closely on the analysis of the four most prevalent 
 complaints of czech dentists .
the 12-month occurrence of different types of health problems and their intensity is given 
 in table 1table 1 .
occurrence of various health problems and their intensityhealth problemintensitynomildmoderatemajorn ( % ) n ( % ) n ( % ) n ( % ) headache227 ( 39.5)229 ( 39.8)101 ( 17.6)18 ( 3.1)neck pain126 ( 21.9)221 ( 38.4)185 ( 32.2)43 ( 7.5)upper back pain289 ( 50.3)130 ( 22.6)135 ( 23.5)21 ( 3.7)low back pain144 ( 25.0)195 ( 33.9)173 ( 30.1)63 ( 11.0)shoulder pain275 ( 47.8)149 ( 25.9)111 ( 19.3)40 ( 7.0)elbow pain412 ( 71.7)107 ( 18.6)46 ( 8.0)10 ( 1.7)wrist pain352 ( 61.2)138 ( 24.0)65 ( 11.3)20 ( 3.5)fingers pain / tingling342 ( 59.5)130 ( 22.6)77 ( 13.4)26 ( 4.5)hip pain344 ( 59.8)149 ( 25.9)65 ( 11.3)17 ( 3.0)knee pain358 ( 62.3)127 ( 22.1)67 ( 11.7)23 ( 4.0)varicose veins371 ( 64.5)113 ( 19.7)67 ( 11.7)24 ( 4.2)carpal tunnel syndrome491 ( 85.4)50 ( 8.7)26 ( 4.5)8 ( 1.4 ) . without regarding intensity , neck pain was the most prevalent musculoskeletal 
 complaint , followed by complaints of low back pain , headaches , shoulder complaints and upper 
 back pain
. however , with regards to intensity , the most common complaint of medium or major 
 intensity reported was low back pain , followed by neck pain , upper back pain , shoulder 
 complaints and headaches . in table 2table 2.univariate associations between low back , neck and shoulder pain and headache in 
 the past 12 months and self - reported risk factorsself - reported risk factorlow back painor ( 95%ci)neck painor ( 95%ci)shoulder painor ( 95%ci)headacheor ( 95%ci)gender ( women)ns1.67 ( 1.142.46)**2.01 ( 1.273.18)**3.57 ( 1.986.44)**age ( by year)1.03 ( 1.011.04)**1.01 ( 1.001.03)*1.04 ( 1.021.05)**nsage24291.001.001.00ns30491.79 ( 1.063.05)**1.84 ( 1.093.10)*1.91 ( 0.96 -3.79)**502.50 ( 1.544.08)**1.86 ( 1.153.00)*3.72 ( 1.996.97)**length of practice
( by year)1.03 ( 1.011.04)**1.01 ( 1.001.03)*1.03 ( 1.021.05)**nsthe occurrence of msds in blood relativesnsnsns1.79 ( 1.192.69)**history of serious msd2.21 ( 1.273.84)**2.02 ( 1.173.48)*2.55 ( 1.464.44)**nsreduction of work load due to msds3.23 ( 2.015.18)**4.41 ( 2.717.20)**4.87 ( 3.047.82)**3.14 ( 1.935.11)**sick leave due to msdsns2.55 ( 1.046.27)*nsnsoperation due to msds2.55 ( 1.145.66)*nsnsnspsychologically demanding work1.89 ( 1.232.88)**2.90 ( 1.834.59)**1.83 ( 1.123.01)*nsmore than 20 patients a day1.56 ( 1.112.20)*1.36 ( 0.961.92)*1.50 ( 1.032.20)*nssitting position0.70 ( 0.500.99)*nsnsnspatient s supine position0.55 ( 0.301.00)*nsns0.44 ( 0.181.06)*x - ray included in the dental unitnsnsns1.53 ( 1.002.33)*short relaxation exercisesnsns1.99 ( 1.263.16)*nssubjective assessment of general healthsatisfactory3.63 ( 2.475.33)**4.01 ( 2.735.91)**3.46 ( 2.305.22)**3.09 ( 2.004.78)**bad / very bad10.91 ( 3.6332.76)**7.01 ( 2.6918.23)**10.99 ( 4.3527.74)**3.90 ( 1.619.46)**p<0.05 * , p<0.01 * * ; or : odds ratio , ci : 95% 
 confidence interval , ns : not significant , the univariate analysis for selected complaints ( low back pain , neck pain , 
 shoulder pain and headache ) is summarized . the intensity of pain was dichotomized and 
 analysed in two categories  no / mild and moderate / major .
p<0.05 * , p<0.01 * * ; or : odds ratio , ci : 95% 
 confidence interval , ns : not significant according to this data , females were especially associated with headaches as well as 
 increased occurrences of neck and shoulder pain , while the influence of age and the length 
 of practice were significant for neck , shoulder and back pain but not for headache .
each 
 additional year of age / year of practice increased the possibility of neck pain by 1% / 1% , 
 low back pain by 3% / 3% and shoulder pain by 4% / 3% .
a history of serious musculoskeletal 
 disease was related to neck , low back and shoulder pain .
dentists who had undergone surgery 
 for msds had an increased risk of low back complaints .
dentists who have already had to decrease their workload 
 due to msds were laden with an increased risk of all analysed complaints with odds ratios 
 varying from 3.14 to 4.87 .
working on more than 20 patients a day remains a significant 
 factor for all of the followed problems except for headache .
the perception of work as 
 psychologically demanding increased the risk of neck , low back and shoulder pain . according 
 to our data , perceived
the sitting position had a positive effect on low back 
 complaints and the supine position of the patient decreased the possibility of both low back 
 pain and headache .
the results of the multivariate analyses on risk factors for the occurrence of low back , 
 neck , shoulder and head complaints are shown in table 
 3table 3.self-reported risk factors and low back , neck and shoulder pain and headache in 
 the past 12 months ( multivariate analyses)self - reported risk factorlow back painor ( 95%ci)neck painor ( 95%ci)shoulder painor ( 95%ci)headacheor ( 95%ci)gender1.25 ( 0.841.86 ) * 1.65 ( 1.082.51)*2.07 ( 1.253.41)**3.12 ( 1.695.76)**age2429nsns1.00ns30491.82 ( 0.873.84)**502.79 ( 1.403.84)**history of serious msdnsns1.99 ( 1.043.84)*nsthe occurrence of msds in blood relativesnsnsns1.73 ( 1.112.71)*reduction of work load due to msdsns2.60 ( 1.494.53)**2.62 ( 1.534.48)**1.88 ( 1.043.38)*psychologically demanding workns2.39 ( 1.463.89)**nsnsx - ray included in the dental unitnsnsns1.64 ( 1.042.60)*subjective assessment of general healthsatisfactory3.32 ( 2.224.95)**3.16 ( 2.064.85)**2.21 ( 1.413.46)**2.69 ( 1.634.43)**bad / very bad10.50 ( 3.4731.80)**4.29 ( 1.5012.25)**4.61 ( 1.6113.22)**2.46 ( 0.867.05)**p<0.05 * , p<0.01 * * ; or : odds ratio , ci : 95% 
 confidence interval , ns : not significant . perceived satisfactory or bad / very bad general health was the strongest risk 
 factor . according to multiple logistic regression analysis , gender was significantly related 
 to all of the above mentioned complaints .
the occurrence of msds in 
 blood relatives increased the possibility of headache . decreasing the workload due to msds 

an x - ray included in the 
 dental unit increased the possibility of headache .
the perception of work as psychologically 
 demanding was significant only for the neck complaint .
p<0.05 * , p<0.01 * * ; or : odds ratio , ci : 95% 
 confidence interval , ns : not significant
in our questionnaire survey the majority of dentists ( 96.9% ) reported an occurrence of at 
 least one of the listed health problems during the past year and 66.3% of the sample 
 reported difficulties of medium or major intensity . by comparing the results of our survey 
 with the results of similar studies from other countries , it can be stated that the 
 situation in the czech republic is roughly average in terms of the rate of occurrence of 
 msds among dentists4 , 6 , 11 , 13 , 17,18,19 . even though the prevalence of msds of medium or major intensity among 
 dentists was quite high , sick
leave for these difficulties was taken only by 4.5% ( n=17 ) of 
 the dentists during the past year29 .
as 
 most dentists work in private clinics with regular patients , sick leave may incur a 
 considerable impact on the economics and goodwill of some dental practices4 . back
pain and neck pain followed by headaches and shoulder complaints were the most 
 prevalent physical complaints of czech dentists , which is in accordance with similar 
 studies2 , 3 , 
 6 , 10 , 13 , 15 , 20 , 32 . in our study ,
musculoskeletal pain for all regions , excluding headache , was associated with 
 age and length of practice .
in contrast , other studies among dentists showed that msds decreased 
 with age and duration of practice10 , 33 , 34 .
their findings were attributed to older practitioners treating fewer 
 patients as a result of age or that more experienced dentists learn to adjust their work 
 posture to avoid such problems , or that those dentists with musculoskeletal problems have 
 left the profession1 , 6 . according to multiple logistic regression analysis , female dentists may be more likely to 
 suffer from headache , back , neck and shoulder complaints than males .
the gender differences 
 in msds that showed women to be at a disadvantage were also reported in other similar 
 studies3 , 11 , 
 13 , 16 , 
 35,36,37 .
akesson et 
 al.16 found that not only did 
 female dentists have higher prevalence of neck , shoulder and hand / wrist symptoms but also a 
 greater occurrence of a combination of these symptoms , as well as a longer duration of 
 symptoms in neck and shoulders during the past 12-month period .
there can be several reasons for these findings , i.e. the different constitution of women , 
 higher susceptibility or lower resistance to constant strain , smaller muscle strength , women 
 also ( unlike men ) pay more attention to and take better care of their health and tend to 
 report health problems more often .
psychosocial factors and stress may also play some 
 role1 , 16 , 
 36 , 38 , 
 39 .
the number of patients treated a day appeared to be another significant factor in our 
 study .
working on more than 20 patients a day increased the risk of all of the mentioned 
 problems except for headache , however , this can be heavily influenced by the dentist , who is 
 usually able to plan the number of patient appointments in advance .
other very important aspects in relation to msds are the psychological demands of work and 
 stress1 , 7 , 
 11 , 20 .
stress amongst dentists is thought to result from many sources , 
 including job satisfaction , business income , working hours , as well as staff / patient 
 interactions4 .
several complementary 
 mechanisms have been suggested in an attempt to explain how psychosocial stress can result 
 in musculoskeletal tension and disorders and/or aggravate the effects of a high physical 
 load40 , 41 .
a central notion is that stress causes an increase in muscle 
 tension similar to that caused by a physical load , especially in the area of the neck , 
 shoulders and upper limbs11 , 39 , 41,42,43,44 . on the contrary ,
some of the analysed factors in our study had a positive effect and 
 therefore , can be seen as protective .
the sitting position had a positive effect on low back 
 complaints and the supine position of the patient decreased the possibility of both low back 
 pain and headache .
this can be due to better loading of the musculoskeletal system during 
 work in the sitting position on the reclined patient24 , 27 .
perceived satisfactory or bad / very bad general health was the strongest risk factor . even 
 though 68.0% of dentists in our study rated themselves as being in good or very good general 
 health , a comparable percentage of them ( 66.3% ) , however , reported at least one of the 
 listed ailments at medium or major intensity .
subjective perceptions and feeling healthy 
 about oneself are important factors that affects the quality of life of individuals45 , but this feeling should not lead to an 
 underestimation of the primary symptoms of msds .
long - term pain , muscle stiffness , loss of 
 grip strength and restrictions of movement can not simply be taken for granted as inevitable 
 in the profession of dentistry29 . in 
 addition , the feeling of being generally healthy even in the presence of certain health 
 problems contributes to the individual perception of pain intensity .
the profession of 
 dentistry has been chosen as an independent occupation , it is relatively well - paid and 
 accompanied by a high social status and in addition , doctors can expect good prospects after 
 their active work years have been completed .
these positive factors can certainly at least 
 partially compensate for the existing health problems and lead to a subjective perception of 
 overall good health .
first of all , it 
 is the representativeness of the sample and the ability of respondents to give correct 
 answers .
although in terms of age and sex the sample of respondents can not be considered 
 representative ( there were significantly more women and the age of our sample was 
 significantly lower than in the entire population of dentists in the czech republic ) , we 
 consider the results of the survey important , as this is the first study of its kind in the 
 country .
questionnaire inquiry is an inexpensive and suitable method , but it can introduce 
 some recall bias . perhaps more accurate results would be obtained by performing physical 
 examinations and assessments , but these methods are time - consuming and expensive . possible 
 selection bias may be present in this study .
it may be that those dentists who chose to 
 participate did so because they had experienced musculoskeletal pain , which would strengthen 
 the results .
high numbers of musculoskeletal problems should make practitioners actively concerned about 
 their early diagnosis and treatment .
further research is required to elucidate the causes of 
 msds among dentists and subsequently it is necessary to focus on appropriate preventive 
 interventions that can help to reduce the prevalence of these problems .
it is therefore important that the education in and the 
 application of ergonomic principles should begin early on , beginning with students of 
 dentistry , and continue throughout the life - long postgraduate education of working 
 dentists .
 the purpose of the study was to describe the occurrence of the most common 
 complaints related to msds in czech dentists and to assess the risk factors affecting 
 them . 
 a questionnaire survey of 581 czech dentists ( the response rate 72.6% ) was conducted 
 in 2011 . 
 the questionnaire ascertained general information about the respondents , their 
 work habits and environment along with the occurrence of musculoskeletal disorders . 
 the 
 respondents filled out the questionnaires during the educational events organized by the 
 czech dental chamber . 
 at least mild difficulties associated with the motoric system were 
 reported by 96.9% of the respondents , with 66.3% of respondents reporting moderate or 
 major difficulties . back and neck pain followed by shoulder pain and headache were the 
 most common complaints in our sample . according to our data : age , gender , length of 
 practice , a history of serious msds , the occurrence of msds in blood relatives , the 
 perception of work as psychologically demanding , and especially a perceived moderate / bad 
 general health were significantly associated with the four most common musculoskeletal 
 complaints . 
 some of the factors were found as protective . 
 this study suggests that msds 
 represent a significant burden for czech dentists and further research is needed to 
 elucidate this issue . 
Introduction
Subjects and Methods
Results
Discussion