An infection control policy was put in place within our dental clinics in 2012 which included safe sharp handling practices, monthly audits and instructions to report, through an electronic incident reporting system within 24 hours of an NSI. Dental HCWs must comply with these however no matter how careful they are, NSIs still occur.
The average annual number of NSIs in dental HCWs in our study ranged from 6 to 11 a year, similar to that found in by Iwamatsu-Kobayashi et al.10 in Japan although the dental setting was university hospitals. The approximate incidence in our study of 7.5 per 100 staff seems lower than that found in a university hospital in Taiwan.9 Some studies reported that underreporting is a common problem. 11,12 However, as our dental clinics have workers’ compensation insurance covering NSIs, and insurance coverage will only be given with reporting of injuries, underreporting may be less prevalent in our study.
In the local context, the incidence of NSIs among our dentists in the primary care setting ranged between 6.9/100 to 20.0/100 across 7 years, with a mean incidence of 13.1/100. This is lower compared to 21.3/100 reported for doctors in a university hospital in 2014.8
Type of device
Needles and dental burs were the commonest devices causing NSI among dentists. This is consistent with other studies done in non-hospital settings.13,14 The third commonest device involved with NSI was the metal matrix band. This is not surprising as placing fillings form the bulk of general dentistry. Majority of injuries occurred on the right hand compared to the left because most of our staff are right-handed. Most of our dental chairs have handpieces placed in the dentist element and may graze or prick their right hand while reaching for instruments. This was similarly observed in another study by Iwamatsu-Kobayashi et al.10 where NSI occurred more commonly during a dental procedure rather than before or after treatment. This was the time where most sharps instruments are handled.
Majority of the NSI in our study were shallow injuries which involved minimal or no bleeding, with no NSI causing deep injuries. We postulated an association between the type of device used and how severe the injury was. However, the type of device was found not to be significantly associated with severity of injury. This was a good finding as it meant minimal harm was involved with a NSI in the dental setting.
Time of the day/day of the week
No significant findings were found in relation to time of the day or day of the week. We were interested to find out if more NSI occurred after midday/mid-week or end of the day/end of the week where one would be more tired and lacked focus. However, this was found not to be the case. However, in other studies, on the working days in the middle (Wednesday) and end (Friday) of the week, and at the hours close to lunch break (11:00 to 14:00) and getting off duty (after 16:00), there tended to be more NSIs.9
Clean or contaminated injuries
Frequency of clean injuries was not significantly associated with a particular staff grade (p = 0.05). We had initially hypothesised that perhaps staff (Health attendants) involved with sterilisation and decontamination would have more tendency to get an NSI from a clean instrument rather than a contaminated instrument. However, this was found not to be the case. This was a good finding as it meant that everyone has the same tendency for clean/contaminated NSI and everyone should be equally vigilant in preventing NSI.
Staff length of service
Our study found that longer length of service was significantly associated with higher tendency for sharp injuries, p = 0.03. This seemed to contradict other studies where staff or students with less clinical experience had greater NSI.9,15,16 As our dental setting is different from a university hospital, the staff population in our study differs and hence the results differ. Perhaps staff who have worked longer within our clinics were less focused and attentive towards safe sharp practices. Hence this reinforced the importance of constant reminders and education for all staff in preventive efforts.
Preventive efforts
Following observation of the above-mentioned trends, we have targeted efforts to prevent NSI. Figure 2 showed some of the safe sharp practices that were implemented in our clinics. These practices are incorporated into dental staff orientation modules and on-the-job training when staff first joins the clinic. This was in the form of videos and demonstrations. Posters containing pictures on safe sharp practices were placed in each room. Yearly infection control competencies and monthly infection control audits incorporating safe sharp practices were also implemented.
Limitations of study
Small sample sizes were used in the comparisons in this study hence there might be bias in the results. This observational study can be improved if we prospectively collect data from subsequent years. In addition, this was mainly a descriptive study. We are unable to determine the causes of the NSI.