From 765 articles reviewed, 31 cases were included in the study. In total, the needlestick information of 6,737 people (4,402 dentists, 1,000 dental health care workers (DHCWs) and 1,335 students) had been reported. The overall prevalence of NSI was 48% at an average of 11.1 months. About 69% of NSI cases were not reported. About 79% of the different groups of DHCWs had injected the hepatitis B virus vaccines. The most important factors affecting the occurrence of NSI were classified into two groups of individual factors (lapse in concentration, stress, lack of adequate trainings, and not using safety precautions) and patient-related factors (unexpected patient movements, anxious and uncooperative patients). The occurrence of NSI during the treatment procedure, doing injections and recapping were the most important procedures causing NSI among dentists.
The overall prevalence percentage of NSI among DHCWs was 48% at an average period of 11.1 months, 37% in high-income countries and 52% in low/middle income ones respectively. Studies evaluating the prevalence percentage of NSI among other health care providers showed lower rate than that among DHCWs [42-45]. Given the high risk of different viral infections such as Human Immunodeficiency Virus (HIV), hepatitis B, hepatitis C and other types of bloodborne infections through blood products in NSI cases, this rate of NSI prevalence is critical [30, 32, 40, 46-50]. The concern increases realizing that according to the results of the studies, about 69% of NSI cases had not been reported by different groups of DHCWs, and about 21% of the workers had not been vaccinated. The results also showed that the prevalence of NSI in low and middle-income countries is significantly higher than high-income countries. Moreover, due to high number of unreported NSI cases in low and middle income countries, the differences between these two countries are expected to be higher than those reported in this study. The possible reasons include: provided with better educational and training courses, using more safety precautions, more appropriate environmente and working facilities in high-income countries. Also, the prevalence percentage of NSI among dental students was higher than that of dentists, which can be attributed to the lack of adequate skills and experience .
The results showed that about 69% of NSI cases were not reported by different groups of DHCWs. This rate is 67% in high-income countries and 69% in low and middle-income countries. Also, this rate is 82% among dentists, 84% among DHCWs and 71% among students. The main factors for failure to report NSI cases include: being too busy (especially dentists), lack of awareness, fear of testing and cross-infection, problems with reporting system and the belief that the exposure was not significant . The rate of unreported NSI cases among dentists was higher than that of the students, which can be attributed to the heavy workload of dentists as well as the students’ belief that the exposure is significant. The most important measures are: implementation of an appropriate and efficient system for reporting and tracking of injuries, training care providers on the risks and consequences of failure to report (and following up) the injury cases, providing incentives and appropriate cultural settings.
The results showed that about 79% of different groups of DHCWs vaccinated for hepatitis B virus. The results of the study conducted by Pruss-Ustun and colleagues showed that, in 2000, about 66,000 cases of NSI-related hepatitis B infections had been recorded among health care providers all around the world . Other studies also highlighted the high prevalence of hepatitis B caused by NSI [53-59]. Considering the high prevalence of NSI and the risk of hepatitis B among dentists, it is essential to pay a special attention to the NSI prevention guidelines and a full coverage for hepatitis B virus vaccination.
Out of 31 articles which were included in the study, only three articles had mentioned the factors affecting the occurrence of NSI. Since a clear understanding of the effective factors related to NSI incidence can play an effective role in planning preventive measures, it is suggested to be considered in future studies. Lapses in concentration, stress, lack of adequate training and not taking safety precautions were the most important factors affecting the NSI incidence. In this regard, many studies have shown that dentists do not take safety precautions in a sufficient manner [60, 61]. The lack of adequate trainings is also an important factor in NSI incidence. To solve this problem, it is recommended that students and dentists take appropriate courses on the Moulage training programs before starting any new treatment procedure.
It is documented that most NSI occurred while injecting and recapping used needles among dentists. In this regard, the use of safety devices can have a significant effect on reducing the occurrence of NSI among dentists [32, 62, 63]. The results of the study by Zakrzewska and colleagues in England showed that the use of safety syringes reduces the NSI incidence from 11.8 to 0 per 1 million hours of work per year . Therefore, it is necessary to take giant leaps to reduce the occurrence of NSI through such measures as the mass production and optimization of safety syringes, reducing their costs, introduce and make the dentists aware of utilizing them.
The main limitation of the present study is that our search for articles was merely in English and Persian languages and all other languages were ignored. Also, due to the fact that only three articles had mentioned the causes of the NSI, further analysis was not possible for this issue.