A Survey of Work-Related Musculoskeletal Complaints among
Dental Hygienists in Kentucky. RaeAnne Szeluga, MSPH
University of Kentucky, Preventive Medicine and Environmental Health
1141 Red Mile Rd, Ste 102, Lexington, KY 40504
Introduction and Background
Musculoskeletal disorders (MSDs) plague the nation’s workforce and have become the focus of study in
occupational investigations. Work-related musculoskeletal disorders arise from normal work activities
that become hazardous when the body is not permitted proper rest periods among other considerations
including job task design. Musculoskeletal disorders (MSDs) are defined as a series of micro-traumatic
events that accumulate in the body and as a result, develop into a more severe injury to the
musculoskeletal system. Risk factors for musculoskeletal disorders include static body positions, highly
repetitive motions, mechanical stress or force, and exposure to vibration or cold temperatures. A number
of musculoskeletal injuries can be avoided if occupational risk factors are identified and preventive
measures are put into place.
In the field of dental hygiene, work-related musculoskeletal disorders have only recently been recognized
as an occupational hazard. The American Dental Association (ADA) recently acknowledged that dentists
and dental hygienists are at risk for work-related musculoskeletal disorders as a result of everyday work
activities.
The purpose of this study was to describe the characteristics of work-related musculoskeletal complaints
among dental hygienists. The following are the specific aims for this study:
1. Identify the prevalence for different anatomic locations of musculoskeletal complaints among
dental hygienists surveyed in Kentucky.
2. Examine the association between work practices and demographic characteristics of dental
hygienists, and musculoskeletal complaints.
3. Determine if dental hygienists with diagnosed medical conditions or neurological disorders have
an increase in musculoskeletal complaints compared to hygienists without previous conditions.
4. Identify whether changes have occurred in daily work practices and personal activities as a result
of musculoskeletal complaints.
There are currently an estimated 100,000 dental hygienists in the United States, of these 1,550 are in
Kentucky. Although there is not an established baseline prevalence estimate for musculoskeletal
disorders, one study documents that 93% of a sample population of dental hygienists report at least one
symptom of a musculoskeletal disorder.
The table below is a compilation of results from recent studies of dental hygienists and shows variables
that were found to be significantly associated (p<.05) with the corresponding locations of musculoskeletal
complaints.
Table 1. Variables Significantly Associated with Corresponding Location of Pain
Hours/
week
Days/
week
Yrs of
prac.
Body
position
Neck
Ylippa
Shoulder
Ylippa
Osborn
Back
Osborn
Osborn
Arms
Osborn
Ylippa
Ylippa
Liss
Liss
CTS
Liss
Liss
Heavy
calculus
pts/day
Prev
med
cond
Min/
patient
Ylippa
Ylippa
Ylippa
Liss
Ylippa
Modify
work
practice
Age
Osborn
Liss
MacDonald
Liss
Osborn
Osborn
Methods
A descriptive cross-sectional study was used in this research. A small sample of dental hygienists
(n=433) served as representatives for the total population of registered dental hygienists in Kentucky
(1,550). A complete member list of state-registered dental hygienists was obtained from the Kentucky
Dental Hygienists’ Association (KDHA).
This study was approved by the University of Kentucky Medical Institutional Review Board (IRB), #9911072. Participation was completely voluntary and there were no personal identifiers. The questionnaire
packet was mailed to all 433 registered dental hygienists in the KDHA. The packet included the
questionnaire with instructions, letter of support, and a pre-stamped reply envelope. Follow-up reminder
postcards listing contact numbers and information were mailed to non-respondents three weeks after the
initial mailing.
A body diagram was designed specifically for use in the research study questionnaire. The design of the
diagram was modeled from NIOSH recommendations. Close-ended questions regarding symptoms of
musculoskeletal pain were included with the pre-coded body diagram. Questionnaires used in two major
research studies regarding musculoskeletal disorders in dental hygienists were obtained from the
authors. Additional questionnaires and information obtained from a review of the literature was also used
as a basis for identification of study variables. The independent variables, or predictors, in the study were
the work practices and demographic characteristics of the dental hygienists surveyed. Other independent
variables examined were the dominant hand of the hygienist, and previously diagnosed medical and
neurological conditions. The frequency and severity of pain in a specific body region made up the
dependent variables, or outcome measures, for the study. Musculoskeletal complaints were identified
defined by the presence or absence of pain in each specific body region.
Survey data was entered into Epi Info, Version 6.25 as it was returned. After initial frequency analysis on
the data, the complete data set was transferred to SAS for Windows. Descriptive statistics were
generated in order to obtain frequency tables for all listed independent variables. Stratified, bivariate
analysis (2x2 tables) was performed using odds ratios (OR) to look at the association between potential
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risk factors (independent variables) and each dependent variable. Some independent variables were
categorical, and others were dichotomous. In analyzing categorical variables, a referent group was
chosen from the categories. From the bivariate analysis, we screened for risk factors that had elevated
odds ratios (greater then 1.5), and included them in a multiple logistic regression analysis for the
dependent, outcome variable. Some possible confounders were controlled for through the use of multivariable analysis. A p-value of <.05 is considered significant. Due to the small sample size and high
reports of pain in a few areas, only four body regions (neck, shoulder, wrist/hand, and lower back) were
examined using logistic regression.
Results
Data analysis was based on a final sample size of two hundred forty five (N=245). Detailed demographic
information and descriptions of work characteristics can been found in Tables 2 and 3.
Table 2. Demographic Characteristics of Female Dental Hygienists in Kentucky
Demographics
Age:
22 - 33 years
34 - 44 years
 45 years
Years of Practice:
1-3 years
4-9 years
10-15 years
 16 years
BMI:
< 20 kg/m2 (underweight)
20 - 24.9 kg/m2 (normal)
25 - 29.9 kg/m2 (overweight)
 30 kg/m2 (obese)
n
%
81
93
70
33.2
38.1
28.7
75
52
37
81
30.6
21.2
15.1
33.1
31
141
52
21
12.6
57.6
21.2
8.6
Table 3. Characteristics of the Work Exposure Patterns for Dental Hygienists
N
Median
Range
Days/week
243
4 days
1-5 days
Hours/day
231
8 hours
3-14 hours
Patients/day
240
9 patients
2-25 patients
Minutes with each patient
245
45 minutes
15-70 minutes
Minutes in between patients
211
5 minutes
1-45 minutes
Minutes in twisted, rotated
235
20 minutes
1-60 minutes
position with each patient
Minutes bent forward with each
patient
236
20 minutes
0-50 minutes
Cumulative Work Hours
Tools used with patients:
Handpiece (# patients/day)
Ultrasonic (# patients/day)
Scalers (# patients/day)
239
6.3 hours
1.8 – 11.3 hours
242
214
243
8 patients
3 patients
8 patients
1-25 patients
1-20 patients
1-15 patients
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Table 4 addresses the self-reported prevalence of musculoskeletal pain in the sample population. Ninety
six percent of the dental hygiene participants in this survey (n=234; 96%) reported musculoskeletal pain.
The four body regions with the highest frequency of pain reported are the neck, wrist/hand, lower back,
and shoulder.
Table 4. Self-Reported Prevalence (%) of Musculoskeletal Complaints Among
Kentucky Dental Hygienists (N=245), 1999
Body Part
n
%
95% CI
Neck
Shoulder
Upper Back
Lower Back
Elbow
Forearm
Hip
Wrist/Hand
Upper Leg
Knee
Lower Leg
Ankle
203
186
148
193
51
84
85
196
33
59
26
55
82.6
75.9
60.4
78.8
20.8
34.3
34.7
80.0
13.5
24.1
10.6
22.4
77.4 - 87.2
70.0 - 81.0
54.0 - 66.5
73.0 - 83.6
16.0 - 26.6
28.4 - 40.6
28.8 - 41.1
74.3 - 84.7
9.6 - 18.5
19.0 - 30.0
7.2 - 15.3
17.5 - 28.3
% Reporting 1
days missed from
work
5.4
5.9
2.7
5.7
3.9
4.8
4.7
4.6
6.1
1.7
3.8
7.3
Approximately forty one percent of the hygienists (n=99; 41%) reported they have modified their work
activities and practices because of discomfort, pain, tingling, or numbness. In addition, twenty seven
percent of the sample (n=66; 27%) modified their daily household activities and thirty two percent (n=78;
32%) modified their leisure activities due to musculoskeletal pain. Other prevention efforts have been
made by the hygienists; a complete list is documented in Table 5.
Table 5. Measures taken by Dental Hygienists to prevent injury or reduce discomfort, pain, tingling, or
numbness.
Preventive Measures
Stretching
Improved posture
Lumbar or chair supports
Proper fitting gloves
Workstation adjustment
More frequent breaks
Reduced work hours
Altering work schedule
Ergonomic instruments
Personal relaxation or meditation
Prescription medication
Over-the-counter medication
Bandage or brace (not prescribed)
Chiropractor
(N=245)
n
168
175
24
117
54
26
42
20
57
54
36
113
37
16
4
Hygienists
%
68.6
71.4
9.8
47.8
22.0
10.6
17.1
8.2
23.3
22.0
14.7
46.1
15.1
6.5
The dental hygienists indicated the most severe and frequent reports of pain, discomfort, tingling, or
numbness in their neck, shoulders, lower back, and wrist/hand. These four body regions were examined
in greater detail. Table 6 summarizes the statistically significant risk factors and protective findings from
the documented literature compared to this research study for the neck, shoulders, back, and wrist/hand
regions.
Table 6. Comparison of Risk Factors (-) and Protective Findings (+)
Previous Research Literature
Current UK Dental Hygiene Study
Neck
Shoulders
Back
Wrist/Hand
- Hours per week
- Body position
- Minutes with patient
- Hours per week
- Days worked per week
- - # yrs practicing DH
- Body position
- Minutes with patient
- Hours per week
- # yrs practicing DH
- Age
- # yrs practicing DH
- Body position
- Heavy calculus patients
- Previous medical cond.
- Minutes bent forward over patient
+ 6-10 minutes b/n patients
- Minutes in a twisted/rotated body
position
- Minutes in a twisted/rotated body
position
- Minutes bent forward over
patient
+ Age (≥ 41 yrs)
+ Working 5 days per week
NOTE: p < 0.05 for all factors listed
Conclusions
In this study, 96% (n=234) of the respondents indicated experiencing musculoskeletal pain over the past
twelve months. Within the sample population, only eleven individuals were free from pain. The
prevalence of musculoskeletal pain estimated in this study was higher than reports from other studies.
A major limitation of this study is the reliance on an individual’s willingness to disclose personal and
health related information. All participants were made aware that the survey was confidential and data
was reported at the group level only. This study also had the potential for recall bias because it is asked
participants to remember musculoskeletal complaints and information regarding the past year. The
participants who experienced pain may be more likely to remember events and volunteer that information,
which leads to response bias. Stress and dissatisfaction with employment was not addressed in this
survey; however, it can influence the amount of discomfort a person experiences in their job.
The dental hygiene profession requires extensive training and education. Dental hygienists often work on
a strict time schedule and have a very regular routine. It is easy to recognize that the more difficult and
heavy calculus patients will require more time and more labor. As a result, the dental hygienists do not
work with hundreds of patients each week and each week often resembles the previous one. The
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hygienists are a good population to answer surveys because they are very aware of their regular work
routines and hazards.
In almost every body region examined, awkward body positions proved to provide the greatest risk for
pain. By educating the hygienists of MSDs and promoting the use of ergonomic chairs and instruments, it
is possible to alleviate some of the risks and pain associated with awkward body positions. In some
cases, the younger hygienists were more at risk for pain then the older hygienists. The older hygienists
may have good methods of preventing pain in work and leisure activities. Also, the older hygienists may
no longer be clinically practicing dental hygiene, or are working strictly as educators in the field. The risks
and hazards of the job may have forced them into other fields or retiring; therefore, it would appear to
have a healthy worker effect.
Although, statistical significance was not widely demonstrated in the sample, the fact remains that this is
a population of individuals who are routinely experiencing pain from work activities. These findings
illustrate the clinical relevance of the study. In examining changes made by the hygienists, as addressed
in the specific aims of the study, it was shown that the hygienists are making attempts to prevent injuries
in their daily work activities. The majority of the sample population reported actively trying to reduce their
risk for injuries by modifying work, leisure, and household activities that were painful. The prevention
efforts may be drastically reducing serious musculoskeletal injuries and reports of severe and frequent
pain. The demographic information of the dental hygienists in Kentucky had not been examined until this
study. With the documented prevalence of musculoskeletal pain for each body region, prevention efforts
may now be more focused and can be addressed. This research project will be taken into consideration
by the KDHA not only for demographic information but to help prevent future injuries in dental hygienists.
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