Impact of educational intervention on dental students’ competence in managing injuries caused by sharp objects: a quasi-experimental study

Abstract

Introduction

Sharp object injuries (SOI) pose significant risks to dental healthcare workers. This study evaluated the impact of an educational intervention on dental students’ knowledge, attitudes, and practice habits regarding SOI management.

Methods

A quasi-experimental before-after study was conducted among 87 dental students (59.8% female, 40.2% male; mean age: 23.45 years) in clinical years (DDS 2022–2025) at Qazvin University of Medical Sciences, Iran. Participants completed a validated 34-item questionnaire (10 knowledge, 7 attitude, 17 practice questions) before and after watching a 3-minute 36-second animated video on SOI management and post-exposure prophylaxis (PEP). Data were analyzed using SPSS 26 with chi-square, ANOVA, and Bonferroni correction (p < 0.0031).

Results

This study revealed significant differences in immediate post-injury performance knowledge (P = 0.001), PEP awareness (P = 0.025), and needle-capping (P = 0.001). However, there was no statistically significant difference in the extent of injury with sharp objects based on sex or age. There was a significant relationship between students’ year of university entry and the extent of injury with a sharp object (P = 0.025). Most students (67.8%) did not know how to function correctly after a sharp object injury, and the highest number of sharp object injuries occurred in the 7th semester. Over 60% of injuries went unreported, primarily due to perceived insignificance (44.1%).

Conclusions

Structured educational interventions, particularly visual aids, enhance SOI management knowledge. However, long-term behavioral changes and reporting compliance require further investigation. Integrating SOI training into dental curricula and fostering a culture of incident reporting are critical to mitigating risks.

Introduction

Occupational hazards such as accidental exposure to sharps, cuts, and crushing are common among Health Care Workers (HCWs), and sharp-object injuries (SOIs) are common and inevitable in HCWs while performing patient care services [1]. According to data from the International Safety Center, the average daily census for needlestick and sharp object injuries in 2023 in the United States was 35.2 needlesticks per 100 healthcare workers, based on reports from 41 hospitals. Of those reports, only 0.2% involved dentists and dental hygienists, while dental students were not included in the data [2]. Dental HCWs, including dentists, dental hygenists, dental assistants, and dental students, are among the groups that face SOIs in their daily work more than most HCW groups [3]. The prevalence of NSI among dental students was reported to be approximately 36.2% in China [4]. The same was revealed in a study in Saudi Arabia, which only involved dental assistants in a city [5]. There was an increase of 44% among dental students, which is a worrying trend [6]. Unfortunately, there is a lack of data and underreporting in this field, as reported in previous studies [6, 7].

The consequences of SOIs extend beyond physical harm, including psychological distress and transmission of bloodborne pathogens such as HBV (30% transmission risk), HCV (3%), and HIV (0.3%) [8, 9]. According to a report by the Centers for Disease Control and Prevention (CDC), only 10% of these injuries are reported [10]. The incidence of hepatitis B in Iran ranges from 1.18% to 3%, peaking in Golestan Province at 5.1%–8.9% [11]. Approximately 190,000 people have chronic hepatitis C, with only 35% diagnosed, and 75% of them are aged 20 to 44 years. The overall prevalence of active hepatitis C was under 0.5%, with 0.3% in the low-risk group, 6.2% in the medium-risk group (including healthcare workers), and 32.1% in the high-risk group, primarily due to injection-drug addiction, with a prevalence of 52.2%. Annual reports indicate an increase in the number of HIV-positive individuals in the country [12]. Studies have shown an overall HIV prevalence of 8 per 100,000 individuals among blood donors and 2.15% among injection drug users [11].

In dentistry, limited space, potential patient movement, and the use of sharp tools increase the risk of exposure to blood, saliva, and secretions. This can facilitate the transmission of infectious diseases like hepatitis and HIV [13]. Sharp object injuries can lead to local infections, neurological issues, anxiety, and depression [9]. With a high prevalence of such injuries and 52.4% of dentists unaware of exposure protocols, there is a clear need for further studies [14]. Inadequate continuous training for healthcare workers (HCWs) can lead to decreased health outcomes and increased costs. Constant training is essential to prevent injuries from sharp objects and to maintain the health of HCWs. Proper knowledge and attitude during such incidents ensure safe responses, while timely testing for transmitted pathogens can alleviate anxiety and improve outcomes [9].

Dental students face significant risks of bloodborne diseases, such as hepatitis B, hepatitis C, and HIV, due to injuries from sharp instruments during clinical training. These incidents may arise from inexperience, improper tool use, inadequate training, or insufficient facilities. All healthcare personnel must receive proper training in standard precautions and are regularly reminded of these protocols [15]. The study aimed to evaluate the knowledge, attitudes, and practice habits of Qazvin dental students regarding injuries caused by sharp objects before and after educational intervention, as this knowledge and attitude can contribute to future planning and improve the performance of dental students at medical universities.

Methods and materials

Study design

The present study was a quasi-experimental, before-and-after interventional study that did not involve the randomization of participants. It was conducted among Doctor of Dental Surgery (DDS) program students at the Qazvin University of Medical Sciences in Iran.

Ethical statement

Our study was approved by the Ethics Committee of the Qazvin University of Medical Sciences under Approval ID IR.QUMS.REC.1398.342. The participants consented to participate in the study before completing the first questionnaire.

Participants and eligibility criteria

To ensure accuracy in the results, we employed a “complete enumeration” sampling method. Participants in the study were selected based on the following criteria: they must be students who have entered the clinical course of dentistry and completed at least one course in a clinical department. Students who were unwilling to participate were excluded from the study.

Questionnaire

The authors designed a questionnaire and ensured its validity through content validity analysis using the content validity index (CVI) and content validity ratio (CVR) [16]. Ten experts evaluated the relevance, clarity, and simplicity of the questionnaire, retaining questions with a CVR above 0.62. The overall CVR was 0.78, and the CVI for the entire instrument was 0.89, with individual item CVIs above 0.79. A test-retest within two weeks determined reliability, with Cronbach’s alpha of 0.74 for knowledge, 0.76 for attitudes, and 0.81 for practice habits. The questionnaire contained three subgroups: knowledge (10 questions), attitude (7 questions), and practice habits (17 questions). The practice habits assessment was limited to the first questionnaire owing to the long-term nature of habit development and the unavailability of students for follow-up.

Educational intervention

A 3-minute 36-second animated video was developed using Corel Video Studio 2018, covering:

• 1. Immediate post-injury steps (e.g., wound cleansing, reporting).

• 2. PEP protocols (initiation within 72 hours, HBV/HIV testing).

• 3. Safe needle-handling techniques (one-handed recapping, sharps disposal).

The video featured voiceover narration and was distributed via an online platform. Participants viewed it once, with instructions to avoid external resources. The material was developed by professionals with expertise in infection control [17].

Outcomes

The knowledge and attitudes of students were assessed before and after two weeks [18]. The educational intervention, along with their practice habits, which were the outcome of this study.

Data collection

The questionnaire was adapted to an online format, with an informed consent form included at the beginning to comply with the personal information protection standards. The participants were informed about the study before completing the questionnaire. To maintain confidentiality and encourage honest responses, no personal information, such as names or student numbers, was collected; instead, unique codes were assigned to each student. After two weeks [18], the questionnaire was distributed again using the same methods and codes to ensure anonymity.

Statistical analysis

Statistical analysis was performed using the SPSS software (version 26), with a significance level set at P < 0.05. Categorical data were presented as frequencies and percentages and were analyzed using the chi-square and Wilcoxon tests. Pre and post-intervention variables were compared using a one-way analysis of variance. To account for multiple comparisons, Bonferroni correction was applied, adjusting the significance threshold to P < 0.0031 to reduce the likelihood of Type I errors.

Results

The total population comprised 122 students. Of these, 105 consented to participate and completed the first questionnaire, while 87 completed the second questionnaire. This resulted in an attrition rate of 17.14%. Among the participants, 59.8% were women and 40.2% were men. The average age of students was 23.45 years.

Knowledge

After analyzing the questionnaires, a significant difference was found in immediate post-injury performance knowledge (P = 0.001), knowledge about PEP (P = 0.001), and capping following the intervention (P = 0.001). (Table 1)

Table 1 Comparison of students’ knowledge and attitudes before and after the educational intervention

Attitude

Based on the data collected, it was found that 1 person (1.1%) never worried about injuries caused by sharp objects during dental work, nine (10.3%) rarely did, 49 (56.3%) sometimes did, and 28 (32.2%) always worried about it. The figure below shows the difference in attitude towards reporting, prevalence, ignorance, and prevention of NSI before and after intervention, which was only significant in its prevalence and reporting (P=0.001) (Fig. 1).

Fig. 1

Attitude differences before and after the intervention

Haste (80.5%), fatigue (58.6%), lack of skill (39.1%), and absence of assistance (43.7%) were considered the main causes of sharp-object injuries among students. Our research showed that being afraid of becoming infected (32.2%), ignorance (56.3%), considering it insignificant (49.4%), lack of time (3.4%), lack of concern about contracting infectious diseases (43.7%), certainty about being vaccinated (28.7%), and feeling ashamed of reporting (37.9%) were the reasons for not reporting injury with a sharp object.

Practice habits

According to the information obtained from the first questionnaire, 69 (79.3%) of the students were vaccinated against HBV, and among them, 48 (55.2%) had their antibody titers checked. Eighteen students (20.7%) stated that they had not received the HBV vaccine. Additionally, among the respondents, 59 (67.8%) had previously been trained about injuries involving a sharp object, and 27 (31%) had not been trained about injuries involving a sharp object. Eighty-four (96.6%) of the studied students had the habit of wearing gloves during dental work. Three participants (3.4%) were unaccustomed to using gloves during dental work.

According to statistics, 81.6% of the students used the one-handed technique or scoop method to cap the needle head. This technique involves placing a cap on a table or tray and inserting a needle. On the other hand, 8% of the students brought the needle head and its cap together at an angle, while 10.3% used the method of directly obtaining the needle head and cap together.

Among the students who experienced injuries from sharp objects, 29.9% were injured by hollow needles, 17.2% by round needles, and 39.1% by other sharp objects. These injuries were more frequent in Semester 7, as indicated (Table 2). Among the students, 60.7% did not report the injury, and the most common reason given (44.1%) was that it was a minor injury. Additionally, in 16.1% of the incidents, the patient was infected, and the student did not receive PEP care after the injury.

Table 2 Comparison of injuries that occurred during semesters (In order of number of injuries)

The highest number of injuries caused by sharp objects was reported in preclinical sections, followed by endodontic and restorative sections (Fig. 2). Among those injured by sharp objects, 60.7% attributed the accident to haste, 19.6% to lack of skill, 55.4% to fatigue, and 21.4% to lack of assistance. The highest number of injuries occurred in the 7 th semester (29 injuries; 87 students), followed by the 8 th semester (18 injuries; 87 students). The effect size for semester-based differences in injuries was η² = 0.327, indicating a moderate-to-large impact of the semester on injury occurrence.

Fig. 2

Dispersion of sharp object injuries in different departments

Discussion

Dentists and dental healthcare workers are among the most vulnerable groups with a high risk of exposure to Sharp object injuries (SOIs) [3]. These procedures include administering local anesthesia, handling endodontic instruments, suturing, and sharps disposal. Dental students, in particular, face an elevated risk due to their inexperience and learning environment [7]. In Iran, students begin patient interactions in their third year and must complete an infection control course before clinical training. However, the importance of this education is sometimes underestimated by both the students and faculty members. This study aimed to evaluate the knowledge, attitudes, and practice habits of Qazvin dental students regarding injuries caused by sharp objects, before and after an educational intervention.

Educational intervention had a significant positive impact on students’ attitudes toward the reporting and prevalence of Sharp object injuries (SOIs). It also enhanced their understanding of post-exposure prophylaxis (PEP) treatment and improved their performance in handling injuries. This intervention aligns with findings from other studies, which highlight the lack of sufficient knowledge regarding PEP management among dental students and practicing dentists [6, 19]. Notably, while a study conducted in Riyadh showed higher levels of knowledge, this discrepancy may be because their participants were final-year students. This reinforces the critical need for additional educational programs targeting dental students and practitioners [20].

The study found that 67.8% of students lacked adequate knowledge on how to respond immediately after a sharp object injury. Before the educational intervention, only 40.2% of participants were aware of the PEP protocol. In comparison, Arepogu’s study indicated that 59% of participants were familiar with the PEP protocol [21]. Even though the participants had received training as part of their curriculum, the low percentage of knowledge before the intervention highlights a significant problem, suggesting that the training provided was inadequate. Several factors could contribute to this issue, including the course material and the training approach. Additionally, students may tend to focus on passing the course to meet graduation requirements rather than preparing for future practice. This mindset can negatively impact their educational experience.

The areas that showed the most improvement in response to the educational intervention were practical skills beneficial to their future practice. Conversely, students performed well in other theoretical areas, likely because those subjects had been reinforced through repetition in multiple courses. This suggests a relationship between repetition and effective learning.

The results of this study indicate that there was no significant difference in the occurrence of injuries caused by sharp objects based on sex. This finding aligns with Mazhar’s research but contradicts Jahangiri’s findings [22, 23]. While Mazhar et al. found no significant difference in the incidence of needle-stick injuries (NSIs) between men and women, Jahangiri’s study reported that women experienced more NSIs than men.

Based on the findings of this study, 56.3% of the students reported that they were sometimes worried about sustaining injuries from sharp objects while working. Another study conducted by Dafaalla et al. among various groups of healthcare workers in a Sudanese hospital revealed that over 83% of the participants were concerned about experiencing NSIs [24].

This study showed that 79.3% of dental students were vaccinated against hepatitis B; previous studies in different countries show ranges from 48% to 81.9% among dental students [23, 25,26,27]. In addition, 55.2% of students had their antibody titers checked. This finding is significantly different from that reported by the Bhandari et al. study (10%) [26]. This can be attributed to the executive protocol used by the faculty to determine the antibody titers of the students before they entered the departments. Additionally, 67.8% of the students had previously received training regarding injury with a sharp object, and 31% stated that they had not been trained regarding injury with a sharp object. Most students (96.6%) had the habit of using gloves during dental work. Overall, 81.6% of the patients used a one-handed or scoop technique when capping the needle, whereas 72% of the patients used this technique in Arepogu’s study [21].

According to the current study, 64.4% of students reported experiencing at least one injury. In other studies, conducted in Iran, the incidence of injuries ranged from 57.42% to 76%, whereas in other countries, it ranged from 33% to 49%, with one study reporting a rate of 98.8%. These findings suggest that the incidence of NSIs is generally higher in Iran than in other countries. This could be attributed to several factors, such as differences in equipment, variations in statistical population, and the duration of the clinical course in the educational curriculum of universities [22, 23, 25, 28, 29].

No significant correlation was found between the year of study (entry year) and the number of injuries caused by sharp objects. However, semester-based differences were notable, with the highest injury rates occurring in the 7th semester (η² = 0.327), suggesting that semester-specific factors may play a more significant role in injury occurrence than in the overall year of study. The variation in injury rates across semesters indicates that factors such as increased clinical exposure, stress, and procedural complexity may have contributed to the observed differences. With an effect size of η²= 0.327, semester-based differences appeared to be substantial and should be considered in future studies on clinical training safety. In Marnejon’s study, similar to the present study, the incidence of NSI in the first years was greater than expected [30]. This could be caused by the stress experienced while working by students in lower semesters, as well as by the lack of sufficient skills while working with sharp tools. Additionally, most injuries involving sharp objects occurred in the Preclinical Department, followed by the Endodontics and Restorative Department, and the Oral and Maxillofacial Surgery (OMFS) department. In Ayar’s study, most injuries occurred in the Endodontics Department, followed by the Prosthetics Department [25], possibly due to differences in the duration of student presence in different departments of the faculty and differences in supervision. Huang et al. reported that the risk in pediatric dentistry is 12 times higher than that in oral surgery. This may be due to the limited workspace and the protective behavior often observed when treating children [31].

In this study, most injuries were caused by “tools and equipment”, followed by “hollow needles”, but in other studies, “hollow needles” were the most commonly reported tool causing injury [22, 31]. This difference may arise from the number of students in the pre-clinic department included in our study, as well as the time spent in the Endodontics department, which increases the likelihood of injuries caused by files and spreaders.

The majority of injuries caused by sharp objects were due to “rushing” [23] and “fatigue” [29, 31]. Unexpectedly, 60.7% of the students did not report their injuries, which was even higher at 66.6% in Mazhar’s study, and lower at 25% in Sethi’s study [23, 29]. According to various studies, the percentage of healthcare workers (HCWs) reporting their injuries ranges from 11.7% to 41.4% [25, 32, 33]. In contrast, in Huang et al.’s study, 71.4% of the participants reported their injuries [31].

Based on the results of the study, the most frequent reason for not reporting an injury caused by a sharp object was “minority of the injury,” followed by “ignorance.” Another study showed that the most common reason was “fear of being blamed or getting in trouble for having NSI” [27]. Salzer’s study in Europe found that around one-third of the participants were unaware of the procedure for reporting NSI cases, and 45% of the participants were concerned that reporting the injury could negatively affect their academic success [34]. Finally, Huang et al. revealed that the most frequently cited reason for not reporting NSI cases was a lapse in concentration [31].

Although no statistically significant difference in sharp-object injuries was found between male and female students, the data did not indicate meaningful variation. Previous studies have reported conflicting results, emphasizing the need for further research to better understand potential sex-related differences in injury risk.

To mitigate risks and enhance the effectiveness of education while reducing the likelihood of sharp object injuries among students, we have several suggestions. Firstly, it is crucial to increase faculty oversight during high-risk procedures. A significant concern in many schools is the shortage of faculty, which can lead to insufficient supervision during first-time practical experiences, potentially resulting in injuries. Additionally, implementing a mandatory reporting system that simplifies the reporting mechanisms can help reduce stigma and ensure that appropriate protocols, such as the PEP (Post-Exposure Prophylaxis) protocols, are activated promptly. Finally, integrating sharp object injury management modules into the preclinical curriculum is essential for better preparation and awareness among students.

Conclusion

This study highlights the vulnerability of dental students to sharp object injuries and the potential benefits of structured educational interventions. Our findings indicate a significant improvement in the knowledge of post-exposure prophylaxis (PEP) and injury reporting following an educational video. However, long-term behavioral changes and practical adherence remain unassessed, warranting future studies with control groups and follow-up. Integrating visual learning tools into dental curricula may enhance SOI management; however, further research is needed to confirm sustained improvements in clinical practice.

Limitations and suggestions

This study has certain limitations. The sample size was relatively small, as the study was conducted within a single academic institution, limiting the generalizability of the results. Additionally, the online questionnaire format introduced potential bias as participants could have sought external answers. While efforts were made to ensure confidentiality and anonymity, response accuracy could not be fully controlled. The study also lacked a control group and long-term follow-up, making it difficult to assess the sustainability of the impact of the intervention. This study did not control for potential confounding factors such as prior clinical experience, workload differences, or variations in supervision, which could have influenced injury rates. This research serves as a preliminary study for a larger trial involving multiple schools to further assess the effectiveness of educational interventions in diverse academic settings. Future research should include larger randomized studies with extended follow-up periods, enhanced quantitative methods, and improved measurement tools to evaluate behavioral changes over time and the practical application of educational interventions.