Mercury vapour release from a dental aspirator

The prevalence of occupational health-related problems in dentistry: A review of the literature

The study was conducted to report on the scope and prevalence of occupational health related-problems experienced by dentists, dental therapists, and oral hygienists in their practice of dentistry.

BACKGROUND

Professional practice and dental training have many risk factors, and the dental team should be able to recognize these factors to protect themselves. The prevalence of conditions related to the musculoskeletal system, stress, percutaneous injuries, ears, and eyes are of concern. The dental team should also not forget hepatitis B, hepatitis C, and HIV as risks in practice. Dental practitioners should protect themselves by self-recognizing risk factors and by maintaining proper working conditions.

METHODS

The study targeted all empirical research, case studies, and systematic literature reviews written in English. All articles selected were subjected to a data analysis process. Data were captured on an Excel spreadsheet and reported in a comprehensive table.

RESULTS

The literature addressing occupational health among dental practitioners included mainly cross-sectional studies and review papers (2001-2016). Forty-nine studies were included in the review. Musculoskeletal disorders remain the most researched occupational health-related problems in dentistry. Eye protection compliance was low among practitioners. Percutaneous injuries especially among young dentists and students were still a concern.

CONCLUSION

Occupational health-related problems are still prevalent in current dentistry practice, despite changes in equipment and surgery design. The reported prevalence of occupational related-health problems and other findings of investigative studies highlight the need for continuous professional education and a need to improve clinical practice aspects of dentistry curricula.

Mercury vapor levels in exhaust air from dental vacuum systems

OBJECTIVE

This study was undertaken to determine mercury (Hg) vapor levels in the air exhausted from dental vacuum systems.

METHODOLOGY

Hg vapor concentrations from the dental vacuum system exhaust ports of three dental clinics were measured utilizing the Jerome 431-X mercury vapor analyzer and the United States Occupational Safety and Health Administration's (OSHA) method ID-140 in units of ng Hg/m3. Air velocity measurements and temperatures were determined with a constant temperature thermal anemometer. Hg emissions per unit time were then calculated in ng Hg/min. Ambient Hg concentrations from a location approximately 1000 feet away from the closest clinic sampled in this study were measured with an Ohio Lumex Inc. RA-915+ Hg vapor analyzer.

RESULTS

Mean Hg vapor concentrations analyzed with the Jerome 431-X were: 46,526, 72,211, and 36,895 ng/m3 for clinic I (110 chairs), clinic II (30 chairs) and clinic III (2 chairs), respectively. Mean Hg vapor concentrations utilizing OSHA method ID-140 were 45,316, 73,737, and 35,421 ng/m3, respectively. Air flow values were: 11.6, 1.8, and 0.5 standard m3/min, respectively. Hg emission data utilizing air flow measurements were calculated to be 532,684, 131,353, and 18,079 ng/min, respectively, (P<0.001). There was no statistical difference between the two methods used to measure Hg vapor concentrations. The mean Hg concentration in ambient air approximately 1000 feet from the nearest clinic sampled was 13.2 ng/m3.

CONCLUSION

The two different methods used to measure Hg vapor concentrations provided similar estimates of Hg concentrations from the exhaust air of three dental vacuum systems. Hg vapor release to the atmosphere from dental vacuums can be substantial and can exceed human exposure limits.

Visual impairment on dentists related to occupational mercury exposure

A detailed assessment of visual function was obtained in subjects with low-level occupational mercury exposure by measuring hue saturation thresholds and contrast sensitivity functions for luminance and chromatic modulation. General practice dentists (n=15) were compared to age-matched healthy controls (n=13). Color discrimination estimated by the area of Mac Adam ellipses was impaired, showing diffuse discrimination loss. There was also reduction of contrast sensitivity for luminance and chromatic (red-green and blue-yellow) modulation, in all tested spatial frequencies. Low concentrations of urinary mercury (1.97±1.61μg/g creatinine) were found in the dentists group. Color discrimination as well as contrast sensitivity function, assessed psychophysically, constitutes a sensitive indicator of subtle neurotoxic effect of elemental mercury exposure.

Twenty years of mercury monitoring in dental surgeries

From 1981 to 2001 disposable mercury monitors based on palladium chloride have been deployed in 3,568 dental surgeries throughout the United Kingdom. They have performed well as first-level indicators of high concentrations of mercury vapour in surgeries that had become contaminated by spillage of mercury or faulty equipment. Whilst accumulated data suggests that mercury hygiene practices have improved over the past 20 years, the move to the use of disposable capsules rather than automatic amalgamators does not appear to have been a major factor in this improvement.