Using the local anesthetic syringe and recapping were the two most important causes of NSI in dentists and dental hygienists. Cleaning instruments, changing the anesthetic carpule, and recapping were the most common activities leading to percutaneous injuries in dental assistants.
Studies from US hospitals also indicated syringe use as the major cause of percutaneous injuries among dental professionals . In dental practice multiple injection must be given over the course of the patient's treatment. These activities place dental professionals at an increased risk of sustaining needle stick injuries. There is a need for safer devices in such practices. Approximately 70% of U.S. hospitals have started using IV delivery systems that do not require the use of needles and the use of safer devices has diminished the risk posed to healthcare workers [7, 18]. The Occupational Safety and Health Administration standards and updated CDC guidelines recommend safe work practices to avoid risky behavior [4, 19]. Improved knowledge and training can reduce percutaneous injuries significantly [20, 21].
To reduce NSI in the dental office there is a need to invest resources into educating employees on the proper use of devices, focusing on administration of local anesthetic, recapping, changing the anesthetic carpule and cleaning of instruments, as these factors contributed to a significant proportion of injuries among dental professionals in this study. Moreover, the training needs to be customized for the type of dental health care worker. The focus of training for dentists and dental hygienists could be prevention of percutaneous during local anesthetic administration, while for dental assistants it could be cleaning of instruments, and changing the anesthetic carpule. Recapping was a common cause of percutaneous in all three categories of dental heath care workers. Another possible strategy to prevent percutaneous injuries could be the re-engineering of the anesthetic needle so that it is less likely to cause injury. Although the benefits of this strategy would accrue in the future, they are likely to be more widespread.
One of the challenges in reaching dental health care workers is that this group is fragmented, often working in smaller places with limited resources for injection safety and infection control. However, as this is a group at risk of being exposed to and acquiring blood borne pathogens through needle-stick injuries, there is a need to develop innovative programming to address the problem, involving resources from government, industry, and professional organizations. We observed high immunization coverage (>94%) for hepatitis B among dental professionals. Infection rates for these pathogens have been on the decline over the past decade due to widespread immunization of healthcare workers for HBV .
The estimated direct costs associated with initial follow-up and treatment for a dental professional who sustained a percutaneous injury ranged from $360 to $1,383. Jagger et al. estimated that the average direct costs of initial treatment of NSI at two US hospitals were $672 and $539 per injury . A single indicator such as direct cost, however, underestimates the true burden the disease placed on the individual. Exposure to blood borne pathogens via needle stick injuries exacts a significant emotional and psychological toll on the victims, the cost of which are difficult to measure [23, 24].
We could not calculate rate of exposure by occupation, as denominator data were not available. However, in 2000 there were 5,670 dental hygienists and 8,420 dental assistants practicing in Washington State as compared with 43,500 nurses, but there were 828 reported needle-stick injuries in dental hygienists or dental assistants as compared with 1048 injuries among nurses between 1995 and 2001 . These data suggest that dental health professionals may be at high risk of needle-stick injuries. The steady increase in the number of claims from dental health care professionals over the time period of this study could be due to a number of factors such as improved reporting, increased number of dental professionals (denominator), increased number of procedures and increase in risk.
The workers compensation data are collected for administrative purposes and not necessarily for research. A limitation of this study, which we could not control for, was that not all needle stick injuries were reported. The problem is further compounded when workers apply for workers' compensation coverage, the definition of an occupational disease may restrict whether or not the affected person qualifies for benefits. Studies show that between 9% and 45% of workers suffering occupational illness file for workers' compensation benefits . The case definition of a needle-stick injury is sensitive to the ANSI z16.2 coding for type, source, and nature of injury claims. Our findings therefore underestimate the actual burden of NSI.