Highlights

Chemical Hazards

The chemical environment is one of the most rapidly expanding components of the work environment because new chemicals and solutions are being introduced regularly.

Many of these chemicals are among those whose health effects may not be known and may pose health problems taking years to manifest.

Many biomaterials and auxiliary products used in dentistry are chemically reactive. Hazardous chemical agents used in clinical dentistry include mercury, powdered natural rubber latex (NRL), disinfectants, and nitrous oxide (N2O). By far the most important and most dangerous of these agents is mercury. Its use in dental amalgam has the potential for continuous occupational exposure of a dental practitioner to mercurial vapor which can be absorbed via the skin and the lungs. The active component in the mercurial vapor has a particular affinity for brain tissue.

Mercury poisoning can be characterized by tumors of the face, arms, or legs and can also be associated with progressive, tremulous illegible handwriting and slurred speech. The exposure risks for mercury can be minimized by careful handling procedures.

The continued use of powdered NRL gloves and disinfectants has predisposed clinical dental workers to hand dermatitis, contact dermatitis, contact urticaria, and allergic dermatitis. The most serious potential hazard associated with the continued use of powdered NRL gloves in dental practice is latex sensitization caused by exposure to aerosolized NRL protein. This can result in dermatitis on the hands. This occurs with such frequency that it is now recognized as an occupational hazard in dentistry, and many dental offices have had to stop using latex materials such as gloves and rubber dams.

In recent studies, the frequency of occupational related dermatosis varied from 21% to 43% depending on the prevailing material used in the various specialties. Transient irritative reactions of the eyes and airways have been observed mostly associated with exposure to volatiles from resin based materials, x-ray chemicals, and cleansers. These include procaine, soaps, eugenol, iodine, formalin,phenol, and other disinfectants. More recently, reactions to methyl metacrylate monomer and elastomeric impression materials have been described and are the focus of intensive research.

Although N2O was for many years believed to have no toxicity other than that associated with its anaesthetic actions, the neurological abnormalities in healthcare workers chronically exposed to N2O have disproved this notion.

Retrospective surveys of dental and medical personnel have linked occupational exposure to N2O with a number of health problems and reproductive derangements.Thus, adequate pollution control mechanisms in accordance with international standards should be adopted.

Potential Chemical Hazards  Summary of Major Control Strategies 
  w.r.t. Engineering (Technical aspect) w.r.t. Administrative  w.r.t. Personal Protection Equipment (PPE)
Exposure to methyl methacrylate used as a filler  Substitution with less harmful product. Maintain adequate general ventilation. Enclosed mixing devices. Local exhaust ventilation.  Develop safe work procedures. Maintain good hygiene practices. Educate workers in the nature of the hazard. Medical monitoring of workers.  Gloves, eye protection and face shields. Respirators based on risk assessment 
Exposure to various metals or silica  Substitution with less harmful product. Maintain adequate general ventilation. Enclosed mixing devices. Local exhaust ventilation. HEPA vacuums.  Develop safe work procedures. Maintain good hygiene practices. Wet mopping where silica is present. Educate workers in the nature of the hazard. Medical monitoring of workers.  Gloves, eye protection and face shields. Respirators based on risk assessment 
Exposure to mercury when handling mercury-containing amalgams  Elimination of mercury containing amalgams. Substitution with less harmful product. Maintain adequate general ventilation. Local exhaust ventilation when removing old amalgams.  Safe work procedures. Educate workers in the nature of the hazard. Monitor work environment following a spill. Ensure good hygiene practices. Store products appropriately to decrease exposure.  Protective clothing, gloves, eye and eye protection, and respiratory protection. 
Exposure to latex from contact with latex gloves or components of medical devices  Substitution with less harmful product. Maintain adequate general ventilation.  Purchasing controls to limit latex containing materials from entering facility. Educate workers in the nature of the hazard, hand washing after glove removal, proper glove donning and removal. Periodic screening of workers.   
Exposure to a variety of disinfecting and cleaning agents in routine cleaning activities related to patient care  Maintain adequate general ventilation. Automatic diluting machines.  Purchase in ready to use concentrations to minimize handling. Worker education. Safe work procedures. WHMIS program and maintenance of MSDSs.  Gloves and eye protection. 
Exposure to scented products that may induce sensitization  Elimination of scented products. Substitution with less harmful products. Maintain adequate general ventilation.  Develop scent-free policies. Educate worker in the nature of the hazard. Post signage in work areas where affected workers work.