Investigation of lung function among dental laboratory technicians.
Bolos, Adrian ; Bortun, Cristina Maria ; Bolos, Otilia-Cornelia 等
Abstract: Occupational exposures of dental laboratory technicians
(inhalation of dusts from grinding and polishing of alloys, resins,
ceramics, and disturbance of olfaction by methylmethacrylate monomer)
may have adverse effects on their health. The study's objective is
to analyze the lung function of dental laboratory technicians and to
assess the influence of air quality from dental technology laboratories
on it. The lung function was appreciated by spirometric testing (Cosmed
Pony FX Desktop Spirometer,), with help of 2 parameters: forced vital
capacity (FVC) and forced expiratory flow in one second ([FEV.sub.1]).
The results show that, duration of employment, hence occupational
exposure is associated with a decrease in [FEV.sub.1]/FVC ratio.
Key words: dental laboratory technician, lung function, spirometric
testing, occupational exposure
1. INTRODUCTION
Dental laboratory technicians have multiple occupational exposures,
which may have adverse effects on their health. The potential
occupational risk factors include chemical, physical, ergonomic and
other job-related factors (OSHA Occupational Health and Safety
Administration, 2002). The health effects of concern include: potential
adverse respiratory effects from inhalation of dusts from grinding and
polishing of metal alloys, resins, ceramics, plaster, and the abrasives
used for polishing (Choudat, 1994), (Parks et al., 1999), (Kelleher et
al., 2000) or acrylates (Nayebzadeh et al., 2000); dermatitis from
contact with acrylates and metals or disturbance of olfaction by methyl
methacrylate (MMA) monomer and health complaints caused by noises,
vibration of hand pieces, and long working hours (Jacobsen et al.,
1996).
Several studies have examined the effects of occupational exposures
on respiratory health in dental technicians. Choudat (1994) reported no
significant differences in lung function and prevalence of respiratory
symptoms between dental technicians and controls, but an increased risk
of pneumoconiosis among dental technicians and a positive interaction
between occupational exposure and cigarette smoking. Selden et al.
(1995) found that 6 out of 37 dental technicians with at least 5 years
of exposure to dust from cobalt-chromium-molybdenum alloys had
pneumoconiosis. This study group also had lower lung function than the
expected values. A study by Radi et al. (2002), reported that dental
technicians had significantly lower percent- predicted values in forced
vital capacity and maximal flow rates at 25% and 50%, respectively, than
did controls.
The effects of occupational exposures on respiratory symptoms or
lung function of Romanian dental technicians were not consistently
reported in previous studies. The associations between dust exposure and
lung function among Romanian dental technicians deserves further
clarification.
The aim of this study was to measure the lung function of dental
technicians and to assess the connection between occupational exposures
to particulate matter and MMA monomer and lung function of dental
technicians.
2. METHOD
Spirometric testing represents an investigation, which examines if
the respiratory capacity of a person/patient is affected. By spirometric
testing, one measures the inhaled and exhaled air volume, in a certain
time lapse. The spirometric parameters of interest are forced vital
capacity (FVC), forced expiratory flow in 1 second ([FEV.sub.1]) and
[FEV.sub.1]/FVC ratio. FVC represents the exhaled air volume, as fast as
the patient can, while [FEV.sub.1] appreciates the air volume exhaled in
one second. During investigation the doctor recommends the patient to
inhale deep, then to blow/exhaust into a tube connected to a device
called spirometer, as intense as he/she can.
This study included repeated measurements of lung function of
dental technicians. 20 dental technicians from different laboratories in
Timisoara were invited to participate in this study. A baseline
questionnaire survey was used to collect information regarding
workers' occupational history, habits, respiratory symptoms and
demographics. A written informed consent was obtained from each
participating subject.
For each dental technician participating in this study, the lung
function was measured on six occasions: at the beginning and at the end
of the shift on Monday, Wednesday and Friday. For these measurements,
Cosmed Pony FX Desktop Spirometer was used. Forced expiratory maneuvers
were performed in a standing position. For each subject, trials were
taken until three acceptable trials were obtained or a maximum of eight
trials was reached.
Next to be performed is the evaluation of air quality from dental
laboratories, by ambient air sampling for MMA, particulate matter and
base metals.
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3. RESULTS
20 dental technicians from different laboratories in Timisoara
participated to this study.
Table 1 shows characteristics of the dental technicians, who
participated at the spirometric testing. Thirty percent of the workers
were current smokers. The average duration of employment as a dental
technician was 7 years. According to the questionnaire, the dust
collectors were used by 80% of the workers.
Means of lung function parameters for the participating workers
before-shift and after-shift on Friday are presented in Table 2. Both
before- and after-shift the [FEV.sub.1]/FVC ratio was significantly
lower for the workers employed for more than 10 years, although
precent-predicted FVC and [FEV.sub.1] appeared to be higher at workers
with more than 10 years of employment. Moreover, when workers were
stratified by cigarette smoking status, means of lung function
parameters, before-shift or after-shift, there were no significant
differences between current/former smokers and non-smokers.
Our results indicate a direct connection between the lung function
of dental technicians and their occupational exposure-workplace air
quality.
4. CONCLUSION
This study appreciated the lung function of dental technicians in
Timisoara. The results appear to be consistent with previous reports of
adverse effects of the occupational exposure on pulmonary function of
dental technicians (Radi et al., 2002), (Suh-Woan et al., 2006).
Use of local exhaust ventilation system decreased the levels of
acrylic dust in dental laboratories. We also recorded that the dust
collector was not used during all the polishing and grinding procedures.
Continuing education about proper use of dust collecting system has been
proposed for these dental technicians.
Nevertheless, duration of employment, hence occupational exposure
was associated with a significant decrease in lung function.
This study is a start line for future research regarding the
influence of workplace air quality on the health of dental technicians.
The next step would be the determination of concentrations of MMA and
elements in particles.
5. ACKNOWLEDGEMENTS
This work was supported by by Project POSDRU/107/1.5/S /78702
(2011), financed from European Social Fund-"Inter-Universities
Partnership for Increasing the Quality and Interdisciplinary PhD Medical
Research through PhD Scholarships-DocMed.net" and by
CNCSIS-UEFISCSU IDEI grant, ID 1878/2008, contract no. 1141/2009.
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Tab. 1. Characteristics of the studied dental laboratory
technicians
Variables
20
Age ears)- mean 30
Sex, n (%)
Male 115 (75)
Female 15 (25)
Cigarette smoking, n (%)
Current smoker (30)
Former smoker (10)
Never 12 (60)
Duration of employment (years)
Job contents
Making crowns and bridges, n (%) 11 (55)
Making removable partial dentures
Metal framework, n (%) (20)
Resin part, n (%) (20)
Making complete denture, n (%) (20)
Making orthodontic appliances, n (%) 1 (5)
Use of dust control equipments
Dust collector, n (%) 116 (80)
Polish or ending in a boxglove, n (%) (20)
Use of personal protective equipments
Plastic face shields, n (%) 13 (65)
Cotton or paper mask, n (%) 15 (75)
Gloves, n (%) 1 (5)
Tab. 2.Mean pulmonary function measured on Friday for all
participating workers and stratified by duration of employment
(P<0.05, two-sided Mest for comparison of means between
workers with >10 versus <10 years of employment.)
Lung function All 10 years of <10 years of
parameters workers employment employment
IV 0 5 15
Before-shift
FVC 9.35 103.64 5.55
[FEV.sub.1] 102.44 105.40 100.29
[FEV.sub.1]/FVC% 86.81 81.96 88.26
After-shift
FVC 8.75 101.45 6.10
[FEV.sub.1] 100.74 104.16 9.63
[FEV.sub.1]/FVC% 86.94 83.16 87.92
