Evaluating Dental Students’ Knowledge and Attitudes Toward Antisepsis and Infection Control: An Educational Intervention Study at a Public University Dental Department

Abstract

Background: Infection control is fundamental in dental practice, especially following the COVID-19 pandemic, which highlighted the variability in students’ adherence to disinfection protocols. This study aimed to evaluate the knowledge, attitudes, and practices of the fifth-year dental students at the National and Kapodistrian University of Athens regarding antisepsis and infection control, and to assess the effectiveness of an educational intervention. Methods: A pre-post interventional study was conducted involving two in-person seminars, supplementary e-learning material, and a structured questionnaire administered before and after the intervention. The survey assessed the knowledge, clinical practices, and attitudes toward infection control, including vaccination history and prior exposure incidents. Results: The intervention led to statistically significant improvements in infection control knowledge, especially in risk-based sterilization strategies, disinfectant classification, and PPE use. Students with prior hepatitis B vaccinations and antibody testing demonstrated higher baseline scores and more significant knowledge gains. However, some misconceptions, particularly regarding surface disinfection and prosthetic care, persisted after the intervention. Conclusions: The findings support the effectiveness of structured educational interventions in improving infection control awareness among dental students. Practical, simulation-based training and earlier curriculum integration are recommended to enhance compliance and ensure safe clinical practice.

1. Introduction

Infection control in dental practice plays a critical role in protecting both patients and dental healthcare professionals from the transmission of infectious agents [1]. Dental procedures frequently involve exposure to blood and saliva, both of which can contain a variety of microorganisms capable of spreading infections within the clinical environment [2]. The use of high-speed instruments and ultrasonic scalers generates aerosols that may contain pathogens, which can settle on various surfaces within the dental operatory [3]. Additionally, surfaces can become contaminated through direct contact with gloved hands, ungloved hands, or contaminated instruments [4]. Surfaces commonly affected include the dental chair, lamp, instrument table handles, X-ray machines, countertops, and flooring [5]. Studies have identified numerous pathogens on these surfaces, including Pseudomonas aeruginosa, Streptococcus pneumoniae, Klebsiella pneumoniae, M. tuberculosis, Legionella pneumophila, and Escherichia coli, along with viruses such as hepatitis B and C, HIV, Epstein–Barr virus, herpes simplex virus, and cytomegalovirus, although the most common isolated bacteria from the various surfaces are species of Staphylococcus, Streptococcus, Pseudomonas, Bacillus, and Micrococcus [3,6]. These microorganisms can survive for extended periods in the clinical environment, emphasizing the need for comprehensive disinfection protocols more than ever [7].

To address surface contamination, various disinfectants are recommended, including alcohol-based solutions, iodophors, phenolic compounds, and chlorine-based agents like sodium hypochlorite [8]. The disinfection protocols used so far typically require the removal of visible contaminants followed by the application of a suitable disinfectant with a recommended contact time of at least ten minutes [9]. While both surface disinfection and the use of protective barriers are effective in reducing microbial load, the choice of method often depends on the type of surface and practitioner preference [10]. A combined approach is generally advised for optimal infection control [4].

The outbreak of COVID-19 in late 2019 drastically changed infection control practices in dentistry [11,12]. Due to the virus’s high transmissibility through respiratory droplets and contaminated surfaces, dental professionals faced an elevated occupational risk [13,14]. In response, infection control protocols were rapidly updated to control the viral spread in dental settings [15,16,17]. Key recommendations included increased frequency of air exchange, disinfection of air conditioning systems, and surface cleaning with agents such as 0.5% sodium hypochlorite, 70% alcohol, or hydrogen peroxide-based solutions [18,19,20,21,22]. Despite the widespread availability of infection control guidelines, research suggests that dental students may exhibit inconsistent compliance and varying levels of understanding regarding these protocols [23]. As is evident from the results of various studies, a large percentage of students are unaware of decontamination protocols or do not apply them in dental clinical practice [24,25,26,27]. Nevertheless, dental students’ knowledge, attitudes, and practices as future practitioners are essential to ensuring a safe clinical environment [28].

In this context, the present study investigates the knowledge, attitudes, and clinical practices related to antisepsis and infection control among the fifth-year dental students at a public university dental department. Additionally, the study evaluates the effectiveness of an educational intervention designed to enhance students’ awareness and adherence to recommended infection control measures. Furthermore, it investigates students’ attitudes toward infection control practices and the extent to which they implement recommended measures during their clinical practice. To address these objectives, the study is guided by the following null hypotheses: H_01- there is no statistically significant difference in students’ knowledge regarding antisepsis and infection control before and after the educational intervention; H_02- there is no significant difference in the self-reported practices related to disinfection, sterilization, and antisepsis pre- and post-intervention; and H_03- the educational intervention has no impact on students’ attitudes toward infection control within dental clinical settings.

2. Background of the Study

Across various countries, compliance with basic infection control protocols among dental students has shown both promising and concerning trends. For example, in Brazil, de Souza et al. (2006) reported high adherence: 99.5% used gloves, 84.2% goggles, and 100% masks [29]. Similarly, Al-Maweri et al. (2015) found 98.8% glove and 90.8% mask usage in Saudi Arabia [30]. In contrast, Singh et al. (2011) reported poor compliance in India, with only 2 of 245 students using all PPE and 61.2% unvaccinated for hepatitis B [31]. Also, Qamar et al. (2020) found that nearly half of Pakistani students did not use hand antiseptics and only one-third wore PPE in clinics [26]. In Turkey, Ataş et al. (2020) reported universal mask and glove use, with 73.6% using face shields and 86.7% hand antiseptics [32]. Additionally, in India, 91.3% disinfected equipment and 61.3% asked patients to rinse antiseptically before treatment [27]. Another Indian study showed 80% compliance with gloves, masks, head caps, and gowns, along with hand hygiene, though most students neglected protective goggles [33].

In addition, vaccination against hepatitis B (HBV) is fundamental to infection control in dental education, yet coverage and serological follow-up vary widely across regions. In Saudi Arabia, 90% of students had received at least one HBV vaccine dose, but only 37.4% underwent post-vaccination antibody testing [30]. In contrast, a study in India found that just 3.8% of students were vaccinated, despite adherence to hand hygiene protocols [27]. Another Indian survey reported that 30% of students were unvaccinated, and many of those vaccinated had not checked their antibody levels [33]. Antoniadou et al. (2024) highlighted the importance of vaccination in the context of occupational exposure, noting frequent clinical injuries among senior students and advocating for comprehensive immunization, sharps handling training, and post-exposure protocols [34]. These findings show global disparities in preventive practices and immunization awareness.

Furthermore, attitudes toward treating patients with infectious diseases vary across studies. In the UAE, fourth-year students were more willing to treat infected patients (68.5%) than fifth-year students (44.4%) [35], while in Yemen, the opposite trend was observed as 58.9% of fifth-year students expressed willingness versus 31.0% of fourth-year students [36]. Gender differences were noted by Noura et al. (2017), with male students more willing to treat such patients than females [37]. One survey showed students were less inclined to treat HIV patients compared to HBV patients (10.9% vs. 3.0%), though most expressed willingness to assist [28]. Among them, 88–89% would adopt additional personal protective measures, 93–95% would enhance instrument disinfection, and 75% would increase dental unit decontamination [28]. In another Indian study, over half of students hesitated to treat infectious patients and did not consistently take detailed histories to screen for HIV/HBV (>40%) [33].

Another recurring theme in the literature is the disconnection between positive attitudes and the actual implementation of infection control protocols. In Jaipur, Deogade et al. (2018) found that although students reported confidence in their knowledge, compliance in prosthodontic clinics varied widely (14.4–100%) [24]. At Istanbul Aydin University, while glove use (93.9%) and dental chair disinfection (91%) were high, only 29.3% of students washed their hands before gloving, exposing hand hygiene inconsistencies [25]. Another survey reported that although most students used masks and gloves consistently, 7.9% never wore masks and fewer than 50% used protective goggles despite availability [28]. The COVID-19 pandemic further impacted awareness and behavior. So, in Turkey, 74.9% of students reported psychological effects from the pandemic [32]. Elagib et al. (2021) noted moderate PPE use in Saudi Arabia and low use in Sudan, with anesthesia and suture needles being the primary causes of injuries [38]. One survey revealed that nearly half of students had been injured during clinical procedures, 55% did not assess the patient’s bloodborne status, and 80.5% failed to seek post-exposure prophylaxis [28]. Also, at the department of Dentistry, University of Athens, high injury rates were recorded, mainly involving needles, with periodontal, endodontic, and restorative procedures posing the greatest risk [34]. Another study found that 90% of students experienced injuries from contaminated instruments, with female students more often exposed to blood or saliva in the eyes [33].

Finally, educational programs on infection control have been periodically implemented for health sciences students [39]. In one study, a training program introduced to second-year dental students in 2004 led to a substantial increase in course pass rates (from 42% to 78%) and improvements in knowledge and vigilance regarding infection control [40]. Similarly, a study among third-year students at a private dental university in India reported significant gains in knowledge, attitudes, and practices following a structured training intervention [41]. Another study using video-based instruction demonstrated a 41% improvement in students’ understanding of protective barriers, PPE, sharps handling, and hygiene practices [42]. A more recent intervention among third-year dental students showed marked knowledge gains, with 96% of participants reporting an improved ability to apply infection control protocols after the program [43]. Likewise, a 2025 survey in Cyprus among sixth-semester students confirmed significant improvements in infection prevention knowledge, reinforcing the value of targeted educational efforts [44].

3. Materials and Methods

3.1. Study Design

This cross-sectional study was conducted using a pre-post interventional design aimed at evaluating the knowledge, attitudes, and practices of dental students regarding antisepsis, sterilization, and infection control. The target population included the 5th-year students at the Department of Dentistry, National and Kapodistrian University of Athens (N = 300). The intervention involved a structured educational approach to assess its impact on improving infection control awareness and behaviors among clinical-year dental students. The study was conducted following the Declaration of Helsinki and approved by the Institutional Review Board and Research and Ethics Committee of the Department of Dentistry (protocol code 127786/11/12/2023).

3.2. Educational Approach

The educational intervention consisted of two seminars, each lasting two hours, conducted in person by the same educator (a specialist on the theme) and focused on key infection control topics such as disinfection, sterilization techniques, surface barriers, and antisepsis protocols. These sessions incorporated visual learning materials, including slides and videos, as well as interactive discussions [45]. Additionally, a live knowledge assessment was conducted before the seminars to gauge the students’ baseline understanding [46]. Following the seminars, students were given free access to supplementary educational materials through the university’s e-class platform under the course “Organization and Management of Dental Practice” [47]. These included downloadable presentations, instructional videos, and official leaflets on decontamination protocols. Students were encouraged to study the educational material at their own pace over 20 days. After this period, the same questionnaire was redistributed to assess any changes in knowledge and attitudes post-intervention.

3.3. Questionnaire for the Study

A structured questionnaire was used to assess students’ knowledge, attitudes, and self-reported practices regarding infection control [48,49]. Administered via Google Forms and accessed through a QR code, the survey was completed using mobile devices for convenience [50]. It was distributed twice, before and 20 days after the educational intervention, to enable direct comparison. Participation was anonymous and voluntary, with no personal data collected.

More specifically, the questionnaire consists of close-ended multiple-choice questions, Likert scale questions, categorical questions, and open-ended questions to comprehensively examine participants’ knowledge and experiences (Appendix A). The structure is divided into two main sections: Part A refers to demographic information and Part B refers to infection control knowledge and practices. Part A collects demographic information through multiple-choice questions: (1) QI, about the gender, (categorical question), and (2) Q2–Q5, ask about the respondent’s place of origin and vaccination history, the doses of vaccination, and the levels of antibodies for hepatitis B (numeric response questions). Part B included 11 questions, Q1–Q11. Q1, through Likert scale questions ranging from “not at all” to “very much”, assessed students’ awareness of disinfectants, sterilization, antisepsis, and COVID-19’s impact on infection control. Q2 included Likert scale questions ranging from “Never” to “Always” and examined the use of personal protective equipment (PPE), hand hygiene, and adherence to safety measures during clinical procedures. Q3 included multiple-choice questions to evaluate students’ ability to differentiate between sterilization, disinfection, and antisepsis in clinical practice and Q4 use Likert scale questions to gauge their understanding of the level of disinfectant action required for specific pathogens (e.g., HIV, HBV, TB). Q5, via Likert scale questions, classified disinfectants based on their effectiveness (e.g., strong, moderate, weak) and chemical composition (e.g., alcohols, chlorine, formaldehyde). Q6 contained multiple-choice questions to gather knowledge of instrument classification based on the risk of infection transmission (critical, semi-critical, non-critical) and Q7, through Likert scale questions, assessed students’ understanding of sterilization methods for different instruments and surfaces based on the risk of infection. Further, Q8 and Q9 included true/false questions to examine the best practices for surface disinfection and decontamination of impressions and prosthesis. Also, Q10 evaluated understanding of tool sterilization, autoclave usage, dry heat sterilization, and the importance of sterilization validation through true/false questions while Q11 included three open-ended questions. These questions allowed respondents to elaborate more on preferred learning methods for disinfection and antisepsis, challenges faced in adhering to infection control protocols, and attitudes toward treating patients with infectious diseases.

3.4. Controlling Bias

Several strategies were employed in the study design and implementation to minimize potential sources of bias and enhance the validity of the findings [51]. Firstly, the questionnaire was used to assess knowledge, attitudes, and practices, and was carefully developed and validated by academic staff (3 staff members, relevant to the subject) to ensure clarity, relevance, and content accuracy. This step helped reduce measurement bias, ensuring that the tool accurately captured the intended constructs [52]. Further, selection bias was addressed by targeting all 5th-year dental students (N = 162 students in total) during their scheduled coursework and clinical activities, offering equal opportunity for participation [53]. To assess potential selection bias, we compared baseline knowledge scores between students who completed both the pre- and post-intervention questionnaires (n = 152) and those who participated only in the pre-intervention phase (n = 51). Independent sample t-tests revealed no statistically significant differences in overall baseline knowledge scores (t = 0.63, p = 0.53), suggesting comparable levels of infection control knowledge at the outset. Similar non-significant results were observed across key domains, including personal protective equipment, disinfection procedures, and sterilization knowledge (all p > 0.05). These findings indicate that the attrition did not systematically affect the composition of the sample, supporting the internal validity of the post-intervention comparisons. Also, the use of QR code access via Google Forms on mobile devices made the process more convenient and inclusive, encouraging broad engagement from the student cohort. Moreover, to limit social desirability bias, participation was completely anonymous and voluntary, and students were informed that no personal data would be collected [54]. Additionally, no incentives were provided, ensuring that students’ responses were not influenced by reward-seeking behavior or external pressures [55]. The use of the same questionnaire before and after the educational intervention also helped control instrumentation bias, allowing for a direct and consistent comparison of responses [56]. The 20-day interval between the intervention and the post-assessment provided students with adequate time to absorb the learning material while also reducing the impact of recall bias from the initial assessment [57]. Response bias was further controlled by assuring students in the instructions that there were no right or wrong answers and that honest responses were critical to the success of the research [58]. Questions were also carefully phrased clearly and neutrally to avoid leading or suggesting wording [59]. Moreover, observer bias was not a concern in this study since the questionnaire was self-administered, and no researcher was present during completion [60]. To add more to this check, non-response bias was also considered. While participation was voluntary, reminders were sent through course communication channels to encourage a high response rate without exerting pressure. This helped ensure that the results were reflective of the broader student population [61]. Finally, to avoid confirmation bias in the analysis phase, the data were coded and analyzed objectively using a licensed statistical software (IBM SPSS Statistics v.29), with no pre-set expectations about the outcome of the intervention as mentioned elsewhere [60].

3.5. Statistical Analysis

Data analysis was performed using IBM SPSS Statistics v.29 to assess the impact of the educational intervention on students’ infection control and disinfection knowledge. Descriptive statistics (means, SDs, frequencies, and percentages) summarized demographic data and knowledge scores. Reliability was evaluated using Cronbach’s alpha, with α > 0.70 indicating acceptable internal consistency [62]. Paired-sample t-tests and Wilcoxon signed-rank tests assessed pre- and post-intervention changes, while independent-sample t-tests and Mann–Whitney U tests examined differences by demographic variables. Effect sizes (Cohen’s d) were calculated, with d > 0.5 indicating moderate effects. Chi-square tests were used to examine associations between categorical variables such as gender and vaccination status. A General Linear Model (GLM) was also applied to assess the impact of demographic factors (gender, year of study, vaccination status, sharp injury history, and place of origin) on post-intervention knowledge. Partial eta-squared (η²) values were reported, with η² > 0.06 indicating a strong effect. Significance was set at p < 0.05. This multifaceted approach enabled a comprehensive evaluation of the intervention’s effectiveness and the influence of demographic and immunization-related variables [63].

4. Results

As shown in

Table 1. Reliability analysis of the questionnaire (Cronbach’s alpha values before and after the educational intervention).

Assessment Sections/Subjects	Cronbach’s Alpha
	Pre	Post
Infection control and personal protective equipment	0.856	0.924
Antiseptic levels against microbes	0.956	0.957
Disinfection, sterilization, and antisepsis (matching)	0.770	0.782
Disinfection levels against microbes	0.969	0.966
Classification of disinfectants (by effectiveness)	0.919	0.927
Classification of dental instruments (by infection risk)	0.897	0.912
Sterilization/disinfection needs (by risk level)	0.803	0.892
True/False: Surface disinfection in dentistry	0.778	0.840
True/False: Impression and prosthetic disinfection	0.848	0.866
True/False: Instrument sterilization	0.825	0.891
Total questionnaire	0.910	0.950

, the questionnaire demonstrated high internal consistency, with Cronbach’s alpha ranging from 0.770 to 0.969 pre-intervention. Post-intervention reliability improved notably in key areas, including sterilization/disinfection needs (0.803 to 0.892) and surface disinfection knowledge (0.778 to 0.840). Overall, Cronbach’s alpha increased from 0.910 to 0.950, indicating enhanced consistency in students’ responses. We presume, then, that the instrument is powerful enough to support the findings of this educational intervention, strengthening the coherence of students’ knowledge across infection control domains.

4.1. The Sample of the Study

The sample was predominantly female, with a slight decrease in female participation from pre- to post-intervention (67.6% to 62.9%). Student participation decreased from 93.82% (152 students) before the intervention to 31,38% (51 students) after the intervention, indicating a notable decline in engagement. Place of origin remained stable, with over half of the participants from Athens (55.1% pre, 54.5% post). The proportion of island regions increased (12.6% to 17.4%), though not significantly (p = 0.624).

4.2. Impact of the Educational Intervention on Knowledge and Perceptions of Infection Control

As shown in Table S1, notable improvements were recorded in PPE and hygiene practices, including more frequent mask changes (p < 0.001), increased patient use of protective eyewear (p < 0.001), and improved disinfection of goggles (p = 0.009) and face shields (p = 0.004). The use of disinfectant solution through suction lines also increased (p = 0.003). No significant changes were found in glove use (p = 0.273), FFP2 mask use (p = 0.977), or surgical cap use (p = 0.242), likely due to high baseline adherence. Also, according to Table S2, the educational intervention significantly improved students’ understanding of disinfectant composition (p < 0.001) and targeted microbes (p = 0.001), indicating enhanced knowledge in these areas. However, no significant change was found in distinguishing between disinfection, sterilization, and antisepsis (p = 0.526), suggesting strong pre-existing competence. Students’ awareness of patient concerns related to disinfection increased significantly (p < 0.001), while perceptions of COVID-19-related disinfection complexity remained unchanged (p = 0.548), reflecting already heightened awareness. Further, in Table S3, students showed significant improvement in identifying quaternary ammonium compounds as disinfectants (p < 0.001), while knowledge of glutaraldehyde, alcohols, and chlorine remained largely unchanged. Instrument classification by infection risk also remained stable, with consistently high accuracy for identifying high-risk tools like scalpels and periodontal scalers. In addition, Table S3 highlights significant improvements in recognizing appropriate disinfection for non-critical items with visible blood (p < 0.001), surfaces with visible blood (p = 0.007), and surfaces without (p = 0.002), indicating a clearer understanding of contamination-based protocols. However, knowledge of procedures for moderate- and high-risk items showed no significant change, pointing to areas needing further emphasis.

As shown in Table S4, students improved in identifying high-level disinfectants (p = 0.008), understanding phenols’ efficacy against non-enveloped viruses (p = 0.026), and correcting misconceptions about using cotton for disinfectant application (p = 0.031). Knowledge also increased regarding impression disinfection, rinsing before lab submission (p = 0.003) and use of phenolics for alginate (p = 0.018). However, misconceptions about antiseptic substitution (p = 0.362), prosthesis disinfection timing, and material damage remained, indicating areas needing further emphasis. Table S5 shows targeted gains in instrument sterilization knowledge: improvements in dry heat sterilization (p = 0.039), oxidative effects (p < 0.001), preheating/cooling phases (p = 0.042), biological indicators (p = 0.039), and awareness of water/air interference (p = 0.014). No significant changes were observed in autoclave parameters (p = 0.727), pre-cleaning (p = 0.385), or material compatibility (p > 0.4), reflecting high baseline knowledge. According to Table S6, post-intervention gains were significant in infection control and PPE (p = 0.005, d = −0.275), disinfectant classification (p = 0.003, d = 0.298), risk-based sterilization (p < 0.001, d = 0.438), and instrument sterilization (p = 0.005, d = −0.275). No improvements were noted in antiseptic levels, general disinfection, or surface disinfection (p > 0.4), while confusion increased in differentiating disinfection, sterilization, and antisepsis (p < 0.001, d = 0.336).

Findings from the GLM analysis (

Table 2. Results of GLM’s between-subjects effects on infection control and disinfection knowledge.

	Infection Control and Personal Protective Equipment			Disinfection, Sterilization, and Antisepsis (Matching)			Classification of Disinfectants (By Effectiveness)			Sterilization/Disinfection Needs (By Risk Level)			True/False: Instrument Sterilization
	F(1)	p	η2	F	P	η2	F	P	η2	F	p	η2	F	p	η2
Education intervention	0.353	0.553	0.001	1.377	0.241	0.003	0.614	0.434	0.002	3.067	0.081	0.008	0.000	0.988	0.000
Gender	1.543	0.215	0.004	0.005	0.945	0.000	0.266	0.606	0.001	0.086	0.769	0.000	4.952	0.027	0.012
Year of studies	0.601	0.439	0.002	0.327	0.568	0.001	0.001	0.975	0.000	0.656	0.418	0.002	0.093	0.760	0.000
Dental school was first choice	1.261	0.262	0.003	0.710	0.400	0.002	0.095	0.758	0.000	0.006	0.941	0.000	0.607	0.436	0.002
Place of origin (ref. other country)
Athens (Greek capital)	3.449	0.064	0.009	1.881	0.171	0.005	4.591	0.033	0.011	1.098	0.295	0.003	2.231	0.136	0.006
Other urban center (prefecture capital)	5.638	0.018	0.014	6.685	0.010	0.016	0.186	0.667	0.000	0.072	0.789	0.000	2.487	0.116	0.006
Mainland region (towns and villages)	2.291	0.131	0.006	0.082	0.775	0.000	1.086	0.298	0.003	2.745	0.098	0.007	0.620	0.431	0.002
Island region (towns and villages)	0.904	0.342	0.002	4.170	0.042	0.010	2.448	0.118	0.006	0.061	0.805	0.000	0.105	0.747	0.000
Vaccinated against hepatitis B	13.500	<0.001	0.033	0.666	0.415	0.002	0.291	0.590	0.001	5.812	0.016	0.014	0.048	0.827	0.000
Checked antibody levels	2.974	0.085	0.007	0.148	0.700	0.000	1.868	0.172	0.005	0.180	0.672	0.000	5.931	0.015	0.015
Had sharp injury in clinic	1.814	0.179	0.005	0.575	0.449	0.001	4.613	0.032	0.011	0.644	0.423	0.002	0.086	0.769	0.000
EduInt * Gender	0.035	0.852	0.000	0.435	0.510	0.001	3.202	0.074	0.008	0.073	0.787	0.000	0.647	0.422	0.002
EduInt * Year of studies	0.391	0.532	0.001	0.748	0.388	0.002	0.019	0.890	0.000	1.790	0.182	0.004	0.016	0.898	0.000
EduInt * Dental school was first choice	0.424	0.515	0.001	0.090	0.764	0.000	0.013	0.911	0.000	0.348	0.555	0.001	0.546	0.460	0.001
EduInt * Athens (Greek capital)	0.148	0.701	0.000	0.461	0.498	0.001	1.323	0.251	0.003	1.163	0.282	0.003	0.557	0.456	0.001
EduInt * Other urban center (prefecture capital)	0.263	0.608	0.001	0.001	0.972	0.000	0.816	0.367	0.002	2.204	0.138	0.005	0.246	0.620	0.001
EduInt * Mainland region (towns and villages)	0.013	0.910	0.000	0.001	0.982	0.000	5.531	0.019	0.014	2.230	0.136	0.006	2.982	0.085	0.007
EduInt * Island region (towns and villages)	0.142	0.707	0.000	0.543	0.462	0.001	0.958	0.328	0.002	0.412	0.521	0.001	0.003	0.956	0.000
EduInt * Vaccinated against hepatitis B	2.010	0.157	0.005	3.340	0.068	0.008	1.069	0.302	0.003	2.406	0.122	0.006	0.314	0.575	0.001
EduInt * Checked antibody levels	9.267	0.002	0.023	2.041	0.154	0.005	0.029	0.864	0.000	0.085	0.770	0.000	0.798	0.372	0.002
EduInt * Had sharp injury in clinic	0.906	0.342	0.002	3.447	0.064	0.008	0.056	0.813	0.000	1.082	0.299	0.003	0.194	0.660	0.000

) revealed limited direct effects of the intervention, with only sterilization/disinfection needs by risk level nearing significance (p = 0.081, η² < 0.01). Gender predicted instrument sterilization knowledge (p = 0.027, η² = 0.012), while place of origin influenced disinfectant classification (Athens, p = 0.033, η² = 0.011) and disinfection knowledge (other urban centers, p = 0.010, η² = 0.016). Hepatitis B vaccination significantly predicted infection control and PPE knowledge (p < 0.001, η² = 0.033) and sterilization needs (p = 0.016, η² = 0.014). Antibody monitoring was also associated with higher sterilization knowledge (p = 0.015, η² = 0.015). A key interaction emerged between the intervention and antibody monitoring (p = 0.002, η² = 0.023), indicating greater gains among immunized students. Extended GLM analysis (Table S7) confirmed these patterns, showing a marginal effect on antiseptic knowledge (p = 0.053, η² = 0.009) and significant interactions between intervention and vaccination status on antiseptic levels and microbial disinfection (p = 0.007, η² ≈ 0.018–0.019). No other interactions were significant. Overall, immunization-related variables exerted a stronger influence than the intervention alone.

As shown in Table S8, gender differences emerged post-intervention: females improved more in infection control and PPE (M = 8.17 to 8.58) while males showed greater gains in instrument sterilization (M = 4.79 to 5.37 vs. 4.45 to 4.92). Other areas showed comparable progress, with minimal change in surface disinfection. Table S9 indicates that vaccinated students outperformed unvaccinated peers at baseline in infection control (M = 8.16 vs. 6.28) and instrument classification (M = 6.31 vs. 4.19) and maintained superior post-intervention scores, especially in infection control (M = 8.52 vs. 7.09). Unvaccinated students improved more in disinfectant classification but remained behind overall. Table S10 shows that students who checked antibody levels scored higher in infection control (M = 8.71 vs. 8.05) and sterilization (M = 5.29 vs. 4.95), while those without checks showed greater gains in disinfection–antisepsis matching. According to Table S11, students without sharp injuries had higher infection control scores both pre- and post-intervention. Those with injury history improved more in microbial disinfection (M = 2.00 to 3.31) but declined in disinfection—antisepsis matching (M = 8.15 to 6.58), suggesting confusion.

4.3. Q11. Open-Ended Questions

Analysis of open-ended responses revealed key insights into students’ perspectives on infection control. For example, in Question 20.1, students favored hands-on learning, including workshops, simulations, and interactive tools like videos and e-learning modules. Many also suggested quick-reference materials such as handbooks. In Question 20.2, cited barriers to consistent PPE use included time constraints, workflow disruption, insufficient training, and limited supply availability. In Question 20.3, most students reported they would use enhanced PPE (e.g., double gloves, FFP2 masks, face shields) for patients with infectious diseases, and recommended scheduling such patients last, using dedicated instruments, and avoiding stigmatization. Further, Question 20.4 highlighted concerns about inadequate training in sterilization and disinfection, with calls for more supervised practice and updated instruction on evolving protocols. Uncertainty around autoclave use, chemical disinfectants, and sterilization techniques further emphasized the need for practical, detailed guidance. Generally, there was a strong demand for updated instruction on evolving protocols and technologies, particularly in response to emerging infectious threats. Finally, uncertainty around autoclave operation, chemical disinfectants, and sterilization techniques further highlighted the need for detailed, practical guidance on these issues.

5. Discussion

This cross-sectional study aimed to assess the effectiveness of an educational intervention designed to enhance dental students’ knowledge and practical understanding of infection control and disinfection protocols. With the increasing emphasis on infection prevention in clinical environments, especially after the COVID-19 pandemic, the intervention was timely and necessary to reinforce fundamental practices protecting patients and practitioners [64]. The fact that Cronbach’s alpha values exceeded 0.90 for the total questionnaire, as well as the improvement in alpha values post-intervention, suggests a more coherent understanding of infection control topics among students because of this action [65].

5.1. General Knowledge Gains

Post-intervention data showed statistically significant improvements in areas such as awareness of disinfectant composition and the types of microbes targeted. These findings suggest that the educational intervention was successful in enhancing students’ foundational microbiological and chemical knowledge relevant to clinical disinfection. However, there was no significant change in knowledge related to the conceptual differences between disinfection, sterilization, and antisepsis. This likely reflects a ceiling effect, wherein students already had a strong baseline understanding of these core concepts. This result is supported by similar previous studies, where authors concluded that students’ general knowledge of infection control issues improved significantly after the educational intervention, which led to an increase in the percentage of students completing the course successfully at the first attempt [40]. Another study that is in agreement with ours was conducted by Prehba et al., where 96% of the students stated that after the intervention, they were much more able to effectively practice infection control [43]. Additionally, Etebarian et al., found that students’ knowledge increased by 48.58%, attitudes by 6.37%, and practice scores by 17% after the COVID-19-related intervention [66]. We further found that the intervention led to significant improvements in certain areas (e.g., infection control, PPE, disinfectant classification, risk-based sterilization needs) [67], but had limited or no effect on others (e.g., antiseptic knowledge, general disinfection, surface disinfection). We also reported a decline in disinfection, sterilization, and antisepsis matching scores, suggesting conceptual confusion introduced or unaddressed by the intervention. This is particularly important and warrants constant educational refinement, auditing, and adherence to national/international guidelines as suggested elsewhere [8].

Improvements in Personal Protective Equipment (PPE) Use

In our study, we recorded notable improvements in PPE-related behaviors, including more frequent mask changes between patients, increased use of protective eyewear by patients, and improved disinfection practices for goggles and face shields following the educational intervention. These behavioral changes reflect enhanced compliance with infection control protocols in the clinical setting. Similarly, the review by Verbeek et al. (2020) [68] emphasized the critical role of proper PPE use in preventing the transmission of highly infectious diseases among healthcare workers exposed to contaminated body fluids. Their meta-analysis found that structured training, appropriate doffing techniques, and consistent PPE use significantly reduced infection risk. They also highlighted the importance of eye protection and facial barriers, which aligns with our findings regarding the increased use and disinfection of protective eyewear and face shields. Thus, we may conclude that educational interventions, as in our study, and evidence-based PPE protocols are mutually reinforcing strategies to improve safety behaviors and reduce occupational risk in clinical environments.

Further, it is important to note that glove use and FFP2 mask usage did not exhibit significant post-intervention changes in our study, which may be attributed to already high levels of compliance at baseline. This trend is consistent with findings by Habibi et al. (2022) [42], who reported mixed outcomes where 15 students demonstrated improved post-intervention scores, while six students showed a decrease, suggesting variability in response to educational efforts. In contrast, Etebarian et al. (2023) documented a notable 17% improvement in students’ protective practices following a targeted educational program related to COVID-19, emphasizing the potential of structured training to enhance adherence to PPE protocols when baseline awareness is variable, like in our case [66].

5.2. Specific Knowledge Areas Affected

5.2.1. Surface and Material Disinfection

Our findings showed that the educational intervention significantly improved students’ understanding of surface disinfection, especially the correct use of high-level disinfectants and phenolic compounds. It also corrected misconceptions, such as the inappropriate use of cotton, which can reduce disinfectant efficacy. These results are consistent with Artasensi et al. (2021), who stress the importance of selecting disinfectants based on chemical properties and avoiding materials like cotton that compromise effectiveness [69]. Despite improvements, some misconceptions remained, highlighting the need for continued emphasis on evidence-based practices. In contrast, a 2022 study reported no significant change in disinfection habits post-intervention [42].

5.2.2. Instrument Sterilization Procedures

In addition, our participants demonstrated improved knowledge regarding dry heat sterilization, the role of preheating and cooling phases, and the use of chemical and biological indicators. However, no significant changes were observed in understanding autoclave-related procedures or tool material compatibility, suggesting these areas were well understood before the intervention. This distinction indicates that the intervention was particularly helpful for less familiar sterilization methods. In contrast to our research, another study conducted among students in India showed that while at the beginning only 40% of the students knew how to use the autoclave correctly, after the implementation of the program, all of them answered correctly to relevant questions [41]. Correspondingly, the lack of knowledge regarding the use of the autoclave is also evident in other studies, such as those by Mohan et al., according to which only 78.8% of students responded satisfactorily to relevant questions [27]. To add more, the greatest improvement was noted in students’ ability to apply sterilization and disinfection protocols based on risk assessment. Following the intervention, students in our study demonstrated a significantly improved ability to select appropriate disinfection strategies for non-critical items, particularly in differentiating protocols based on the presence or absence of visible blood. This reflects a clearer understanding of contamination-based risk assessment and the corresponding selection of disinfectants. These findings align with the concerns raised by Curran et al. (2019), who discussed the controversies surrounding the use of chemical disinfectants in low-risk healthcare environments [70]. They emphasized the fact that misapplication of disinfectants, particularly in settings where visible contamination is absent, can lead to unnecessary chemical exposure, increased costs, and environmental concerns, without additional clinical benefit. So, we agree on context-specific disinfection practices, aligned with evidence-based guidelines, to optimize both patient safety and resource use, as also mentioned elsewhere [71].

5.2.3. Classification of Disinfectants

Our study demonstrated that educational intervention significantly improved students’ ability to correctly classify disinfectants, particularly quaternary ammonium compounds (QACs), which are often less familiar to students compared to more widely known agents such as glutaraldehyde and alcohols, for which post-intervention gains were less pronounced [72]. This suggests that prior exposure and familiarity limited the observable impact of training for commonly used disinfectants, while newer or more specialized agents benefited more from explicit instructional emphasis. This finding is especially relevant in the context of evolving disinfection practices. As noted in the recent literature, the high-level disinfectants, such as aldehydes and intermediary or low-level disinfectants such as QACs, have become increasingly common in response to emerging pathogens and heightened infection control requirements [73].

Further, alcohol-based solutions are widely recognized for their dual role as both antiseptics and disinfectants [74]. Ethyl alcohol has long been used for hand disinfection due to its rapid antimicrobial action [75]. However, recent evaluations under the European REACH regulation have raised concerns regarding potential health risks associated with repeated skin exposure to ethyl alcohol, particularly its classification relating to fertility and reproductive toxicity [76]. Despite these concerns, a substantial body of scientific literature and numerous commercial products continue to support the use of ethyl alcohol and isopropyl alcohol, typically in concentrations of 43%, 55%, or 72–73%, for surface disinfection [73,77]. These alcohols are often formulated in combination with quaternary ammonium compounds (QACs) or benzalkonium chlorides (BACs) to enhance their efficacy against a broad spectrum of pathogens [78]. This widespread application highlights their continued relevance in infection control protocols, particularly in clinical and dental environments [79].

Educational efforts must therefore evolve accordingly to reflect changing disinfection protocols and emerging agents. However, as it is cautioned, this increased reliance on QACs, while effective in microbial control, raises concerns about microbial tolerance and the potential contribution to antibiotic resistance [73,80]. Therefore, it is essential to educate students on the responsible, evidence-based use of QACs, as indiscriminate application may contribute to cross-resistance in healthcare-associated pathogens. This report is on the importance of integrating antimicrobial stewardship into infection control training [81]. Our findings thus highlight the need for both foundational knowledge of disinfectant classification and awareness of the broader microbiological and public health implications of disinfectant use [69]. Educational programs should aim then not only to address knowledge gaps but also to promote safe, rational, and context-appropriate disinfection practices, aligned with current scientific evidence and global health priorities [82]. As such, structured training on the proper use of these agents is increasingly imperative [81,82,83].

5.2.4. Prosthetic and Impression Disinfection

Significant knowledge gains were seen in protocols for rinsing impressions before laboratory submission and in the application of phenolic compounds for alginate impressions [84]. However, confusion remained among our students regarding the optimal timing of disinfection and potential damage from disinfectants on certain prosthetic materials, as also mentioned elsewhere [85]. According to a recent study conducted among dentists, 67.5% of them do not disinfect their impressions because they are worried that the disinfectants will damage the impression, while a large percentage of those who disinfect them do so in the wrong way [86]. A similar survey among dental students found that only a small percentage of them knew how to properly disinfect dental impressions and prostheses [87]. On the other hand, a survey among dental students in Nepal showed that students’ ability to manage infection control in prosthodontics was generally satisfactory, while few were well versed [88]. These results suggest the need for more detailed instruction and hands-on practice in this area.

5.2.5. Student Awareness of Waterline Contamination and Associated Risks

As reflected in their open-ended responses, several students expressed uncertainty about the microbial risks associated with dental unit waterlines (DUWLs), highlighting gaps in theoretical knowledge and practical training regarding equipment-related infection control [89]. These concerns are consistent with evidence indicating that DUWL contamination primarily affects the lines delivering water directly into the patient’s mouth during procedures [90]. If not adequately maintained, these lines can harbor biofilms and pathogenic microorganisms, posing infection risks, particularly for immunocompromised individuals [91]. In contrast, drain lines, though essential for overall hygiene, generally do not present a direct risk to patients unless malfunction-induced backflow occurs [92]. However, field studies show that heavy microbial contamination can extend from the dental chair through suction lines to the suction unit and associated drain lines, further underlining the importance of comprehensive maintenance protocols [93,94]. Effective products for biofilm management typically include low-foaming surfactants, disinfectants, and deodorizing agents, with enzyme-based formulations at neutral pH offering highly effective biofilm disruption [95]. Overall, ensuring waterline safety requires regular disinfection, the use of appropriate biofilm-control agents, and continuous monitoring of water used intraorally, in line with sustainable dental practice standards [96].

5.3. Demographic and Contextual Influences

5.3.1. Gender Differences

Gender analysis revealed differing patterns in knowledge improvement. Female students showed greater gains in PPE-related knowledge, while male students exhibited more improvement in instrument sterilization. These findings may reflect gender-based differences in clinical task distribution or previous training experiences [97]. Other studies, in which no educational intervention was carried out, show that there was no significant difference in the knowledge about infection control among male and female students [96]. Further, according to another study, there is a statistically significant difference between male and female students regarding the use of face shields (with females using them at a higher rate) and the use of head caps (with males using them at a higher rate). Neither in this study was any educational intervention carried out, as in our case [37].

5.3.2. Impact of Hepatitis B Vaccination and Antibody Checks

In our study, students who were fully vaccinated against hepatitis B and those who had checked their antibody levels performed better at baseline and demonstrated more significant improvements post-intervention [98]. In contrast to our study in a recent survey among dental students by Mohan et al., it was found that although 98.8% of the students were aware of the importance of immunization against the hepatitis B virus, only 3.8% of them were vaccinated. Even though most of them were not vaccinated, the survey showed that most of the students practiced effectively the required means of infection control during their clinical practice [27]. Our study then reinforces the association between hepatitis B vaccination and higher levels of infection control knowledge, with vaccinated students consistently outperforming their unvaccinated peers across multiple domains. This aligns with global perspectives, which emphasize that while significant progress has been made in hepatitis B vaccination coverage, gaps in awareness and follow-up practices, such as post-vaccination serological testing, continue to challenge global elimination efforts [98]. Similarly, targeted educational interventions within primary care settings significantly improved hepatitis B screening and vaccination rates elsewhere, further supporting the role of structured programs in enhancing both coverage and awareness [99].

6. Interpretation of Effect Sizes and Statistical Significance

Effect sizes for knowledge improvements ranged from small to moderate, with the largest observed in risk-based disinfection knowledge (Cohen’s d = 0.438). Some areas, such as basic definitions and PPE use, showed limited change, possibly due to a ceiling effect from high baseline knowledge. General Linear Model (GLM) analyses further revealed in our study that demographic factors, especially vaccination status and geographic background, had significant predictive value for knowledge gains, suggesting there is a complex connection between educational interventions and personal background [100,101].

7. Implications for Practice and Curriculum Design

Our findings show the importance of systematically integrating infection control education across both preclinical and clinical phases of dental training, as already supported recently [43]. Early exposure to infection prevention, before clinical entry, was also recommended by our students, who suggested an earlier and more structured inclusion of this content within the curriculum. In addition, emphasis should be placed on risk-based disinfection protocols, classification of disinfectants, and evidence-based decision-making, as outlined by Rutala et al. (2023) [8]. Students strongly recommended more practical training, including supervised use of autoclaves, step-by-step demonstrations of sterilization cycles, and clinical implementation of disinfection procedures. These suggestions are in line with the literature supporting simulation-based and experiential learning to improve adherence and retention [102,103]. Students also called for the use of visual and interactive tools, such as educational videos and case-based modules, as well as frequent reinforcement sessions throughout the academic year. Additional feedback from our students highlighted the need for more in-depth instruction on chemical disinfectants, including their composition, usage, material compatibility, and associated risks. Logistical concerns were also raised regarding course scheduling, with students preferring integration of infection control sessions into clinical hours, rather than as separate seminars, to enhance accessibility and participation. Recent studies further support the effectiveness of such structured educational approaches. For example, Etebarian et al. (2023) demonstrated significant improvements in knowledge and practices following a COVID-19-focused webinar, while Chaturvedi et al. (2022) and Habibi et al. (2022) documented increased protocol adherence following multimedia-based and formal infection control training interventions [42,66,104].

In conclusion, we would like to highlight the fact that the responsibility for implementing and overseeing infection control protocols ultimately rests with the dentist, who, as head of the dental team, holds accountability for the safe operation of the clinical environment, suggesting that our students should be educated for this role. According to the Council of European Dentists, dentists are expected to supervise decontamination, disinfection, and sterilization procedures, particularly when auxiliary staff, such as chairside or clinical dental assistants, lack sufficient training or are in the process of obtaining formal qualifications [105]. So, there is a need for comprehensive infection control training not only at the undergraduate level but also for all members of the dental team. Furthermore, from a public health perspective, the Centers for Disease Control and Prevention (CDC) emphasize that infection control is a critical component of disease prevention and epidemiological practice, requiring systematic education and vigilance at all levels of healthcare delivery [106]. These insights reinforce our findings, pointing to the importance of integrated, role-specific, and team-oriented infection control education to ensure safety and regulatory compliance in oral healthcare settings.

8. Strengths and Limitations

This study has several limitations. First, reliance on self-reported data may have introduced response bias, particularly social desirability bias, as participants might overreport positive behaviors or knowledge to align with expectations, a concern noted also by Rosenman et al. (2011) and Teh et al. (2023) [107,108]. Second, the post-intervention assessment occurred shortly after the educational session, limiting evaluation of long-term retention. Future research should include delayed or longitudinal follow-ups. Third, a slight decrease in sample size post-intervention may have affected statistical power and generalizability, despite the modest imbalance [109]. Additionally, the intervention had limited impact in domains with high baseline knowledge (e.g., glove use, autoclave familiarity, instrument classification), suggesting a ceiling effect. Lastly, as the study was confined to a single dental school, external validity may be limited due to institutional differences in curricula and resources [110,111]. Nonetheless, the study’s pre-post design, use of both quantitative and qualitative data, and high internal questionnaire consistency support the reliability of its findings. Future studies should replicate this model in varied settings, incorporate control groups, and explore alternative teaching strategies, such as simulation or case-based learning.

9. Conclusions

Dental students recognized the value of infection control training and emphasized the need for increased practical, hands-on learning, ideally integrated earlier in the curriculum. The intervention led to significant improvements in knowledge, particularly in under-addressed areas such as surface disinfection and disinfectant classification. Variation in outcomes based on gender and immunization status suggests that tailored educational strategies may enhance effectiveness. Overall, the findings highlight the importance of ongoing, structured, and skill-based infection control education to ensure safe and compliant clinical practice in dentistry.