Risks and Awareness of NIHL Among Dental Students: A Scoping Review

ABSTRACT

Background and Aims

Although noise exposure levels in the dental professional sector may be considered low when compared to other occupations, noise prevention strategies, especially for the students, are necessary to conserve hearing for this population group. The current scoping review aimed to ascertain the risks and awareness of NIHL among dental students globally.

Methods

The review selected articles from 2014 to 2025, including both quantitative and qualitative studies, existing systematic reviews, and grey literature. The PCC (Population, Concept, Context) framework was used to guide the articles' eligibility criteria. Databases included PubMed, CINAHL, ProQuest, Scopus, Web of Science, and EBSCO Host. The Covidence data extraction tool, which enabled consensus checking, was used to guide the extraction process, and studies were reported according to the PRISMA guidelines. Sixty‐nine studies were initially extracted, and after screening, 10 met the study criteria. Thematic analysis was used to synthesize the narrative data.

Results

Of the 10 studies analyzed, eight indicated risks associated with NIHL among undergraduate students. The use of high‐speed handpieces during clinical training increased the risk for NIHL, with some students reporting symptoms such as tinnitus following the use of the equipment. Four articles reported on the awareness of noise exposure levels and associated risk for NIHL among the students.

Conclusion

The review suggested that there was a risk of NIHL among dental students, particularly linked to cumulative noise exposure. However, awareness of NIHL among the students was poor; therefore, early identification, risk assessment, and awareness of the risks at undergraduate training are necessary for the active prevention of hearing loss. There is a need to encourage listening behaviors that promote awareness towards the prevention of NIHL for this group of students.

1. Introduction

The World Health Organization (WHO), in the World Report of Hearing released in 2021, estimated that by 2050, one in four people will be diagnosed with a hearing problem, and that of 2.5 billion people affected by hearing loss, 80% of those will be from the low‐middle income countries (LMICs). Noise‐induced hearing loss (NIHL) is included in 80% of the common types of hearing loss that affect the working population, and leads to a permanent, disabling hearing impairment, as reported in various industries where excessive occupational noise exposure is a risk (WHO). Although the risk for NIHL was mainly defined as excessive noise exposure levels exceeding 85 dB(A) for an extended period during a daily work shift of 8 h [1], in the dental profession, most activities have indicated noise exposure below 85 dB (A). However, the cumulative nature of noise exposure over an extended period has been reported as a possible risk of NIHL for dental professionals [2].

Since NIHL causes permanent damage to the outer hair cells in the inner ear, restricting the transmission of the stimulus through the sensory and neural pathways to the brain, this leads to irreversible hearing impairment [3]. NIHL has been linked to systemic health issues such as stress, increased blood pressure, and risk of cardiovascular diseases. Furthermore, the constant strain on the auditory system can result in cognitive impairment [4]. Previous studies indicate that the severity of hearing impairment and its impact on the individual's quality of life (QoL) are attributes associated with NIHL, and related to the intensity of the noise exposure, the duration of exposure, and the individual's susceptibility to hearing loss [5, 6]. Evidently, NIHL reports indicate nuanced risks, with the subsequent increase in the prevalence rates globally, and it has been reported as a major public health concern [7]. Thus, NIHL prevention is crucial to reduce its prevalence rate globally and avoid the possible negative impact on the individual's quality of life [8, 9].

According to the National Institute for Occupational Safety and Health (NIOSH), professionals in dentistry are exposed to noise levels that increase their risk of NIHL [10]. Furthermore, dental professionals may be at an increased risk of developing NIHL due to the cumulative nature of noise exposure levels from the various equipment used in their practices [2, 11, 12, 13]. Even though noise exposure levels in the dental professional sector may be considered low when compared to other occupations, noise prevention strategies, especially for the students, are necessary to conserve hearing for this population group. Therefore, increasing awareness for hearing loss prevention and advancing surveillance hearing health coverage allows for targeted and widespread interventions, which could benefit dental professionals [2, 9]. Previous research has shown that educating the dental professionals on the dangers of noise exposure and implementing effective prevention strategies to reduce noise exposure levels could reduce the incidence of NIHL among dental professionals [8]. It must be noted that most of the studies on the prevalence and risks for NIHL in dentistry focused on dental practitioners and not so much on students practicing in similar clinical conditions. Therefore, a dearth of literature investigating the risks of NIHL for students training toward dental professional degrees.

Noise‐induced hearing loss in the dental profession may be caused by a variety of equipment, including high‐low‐speed handpieces, high‐low‐volume suction, and ultrasonic scalers [10]. In addition, some processes and equipment, for example, cleaners, mixing devices, and air conditioning units, have been associated with the risk for hearing loss [14]. Some dental instruments generated noise levels that exceeded 85 dB(A), but their noise exposure levels and their duration of use vary [1, 10]. Therefore, ways of measuring noise emissions should account for such variations in exposure to accurately account for the risk associated with noise exposures for dental professionals. Nevertheless, there is limited literature around noise measurement methods used to track noise exposure levels across various settings in dentistry, during student training, and in independent practices.

Some studies reported that the newer generations of dental equipment used in students' training are less noisy than the previous generations, hence the effects of NIHL may not be significant [15]. However, the use of combined instruments, the new and old generation pieces, still exists in many practices, with knowledge gaps around the effects of noise exposure and the risk for NIHL. Additional studies have also suggested that poor listening behaviors related to the increased use of personal listening devices (PLDs), such as in‐the‐ear headphones, among young adults, could pose cumulative effects of NHIL among dental students [16]. Hence, our scoping review aims to ascertain the risks and awareness of NIHL among dental students globally. The findings are hoped to assist in developing an awareness program aligned with safe listening guidelines that could protect students from detrimental hearing loss and thus advance early hearing healthcare [15].

2. Methods

The scoping review, guided by the Colquhoun et al. [17] framework, which was built on the work of Arksey and O'Malley [18], was used for the study. Article selection included quantitative and qualitative studies, existing systematic reviews, and grey literature. The broad research strategy was considered appropriate for clarifying emerging evidence on the topic and identifying existing gaps [19]. In addition, the qualitative and quantitative data from the literature complemented each other in analyzing the current study findings [20].

2.1. Materials

The Population Concept Context (PCC) framework was used to guide the eligibility criteria [20]. The population of interest includes the dental students globally. The concept of interest is risk and awareness of students working in a clinical setting. The context involves dental students involved in clinical work at dental schools globally. Both peer‐reviewed journal articles and grey literature were considered. Only papers sourced in English were included. See Table 1 for more details on inclusion or exclusion criteria.

Table 1.

Inclusion and exclusion criteria.

Inclusion criteria	Exclusion criteria
English papers
Peer‐reviewed articles and grey literature	Opinion pieces/editorials/reviews
2014–2025
Dental Students practicing in dental schools
Dental students, oral hygiene students, dental therapy students	Dental technician students, dental nurse students
Global

2.2. Search Strategy

The search timeline was from 2014 to 2025. Data searches were from 2014 since more studies from this period covered regions across the globe, and the current scoping review included studies published globally. Databases included PubMed, CINAHL, ProQuest, Scopus, Web of Science, and EBSCO Host. The initial search included relevant Medical Subject Headings (MeSH) and keywords from the first round of papers obtained, which were used as a form of verification in the initial search. The final stage involved checking paper references to ensure that no relevant references were missed during the process. The search terms are as follows:

(((((((((((Dental students) OR (Oral health students)) OR (Oral hygiene students)) OR (Dental Therapy students)) AND (Hearing loss)) OR (Noise Induced)) AND (Risks)) OR (Effects)) AND (Awareness)) OR (Knowledge)) AND (Dental noise)”.

2.3. Extracting and Charting the Results

Figure 1 illustrates the data extraction processes followed by the authors. The PRISMA guidelines were used, which included the following steps: (1) identification of relevant papers through databases and removing duplicates; (2) screening by title, followed by screening the abstract, and the final steps would include (3) assessing for eligibility and identifying included articles [21]. To minimize bias, two independent reviewers evaluated the title and abstract of each article as aligned with our aims and objectives. Furthermore, the Covidence data extraction software, which allowed for consensus checking, was then used for the screening of the articles and the data extraction process. Completion of the data extraction form was an iterative process among the two reviewers; when consensus was not reached, we interrogated the article together in a meeting till agreement was reached.

Figure 1.

PRISMA 2020 flow diagram.

2.4. Analyzing and Summarizing the Results

The findings of the review were analyzed using thematic analysis for qualitative papers and descriptive summary statistics for quantitative papers. Triangulation of both approaches was used to finalize the interpretation and provide a summary of the findings. A narrative synthesis was then used to describe the scope and distribution of literature included in the review.

2.5. Ethical Considerations

The research complied with the fundamental ethical principles [22]. Research ethics approval was obtained from the University of the Witwatersrand Human Research Ethics Committee (Ethics waiver).

3. Results

Out of 69 research studies identified after the search,10 articles met our inclusion criteria. All the articles were of a cross‐sectional design. Saudi Arabia and Chile had two articles each, and one article each came from the UAE, Jordan, India, New Zealand, Malaysia, and the United States of America (see Table 2). The study population in the articles included dental students and dental practitioners, and a study in Jordan included dental technicians and assistants as well. Two studies, one from Chile and the other from Malaysia, additionally included non‐dental students who were analyzed as comparator groups.

Table 2.

Risk and awareness of NIHL among dental students.

Title	Authors and country	Aim	Study design	Population	Risks	Awareness
Noise levels, noise annoyance, and hearing‐related problems in a dental college	Ahmed and Ali (2017) [23] (United Arab Emirates)	To examine and determine the noise levels in clinics and laboratories in one of the colleges of dentistry in the United Arab Emirates (UAE)	Cross‐sectional study	Dentistry College students from the first to the fifth year of study. (n = 114)	The prevalence of noise annoyance and auditory‐related problems was high among students in the second, third, fourth, and fifth levels as compared to the first level. Noise level at the college was below the risk of NIHL of 85 dB(A).	The majority of the students were unaware of the health effects of noise and methods of prevention.
Impact of noise on the hearing and tinnitus among dental students, interns, and dental practitioners: a cross‐sectional study	Alhaider et al. (2023) [24] Saudi Arabia	To assess the impact of noise on hearing and tinnitus among dental students, interns, and dental practitioners. To analyze the knowledge and awareness of dental professionals regarding the impact of noise on hearing and the protection of ears	Cross‐sectional study	Dental students and staff in the dental department (n = 100)	Maximum noise levels from the laboratory (77.33, SD = 1.36). 2% of participants exposed to noise had hearing loss. 29% had tinnitus.	Dental professionals and students had limited knowledge on the effects of NIHL.
Knowledge, attitude, and practice of dental students and practitioners toward noise‐induced hearing loss in Saudi Arabia: a cross‐sectional analytical study	Alnemare (2019) [25] Saudi Arabia	To assess the knowledge, attitude, and practice of dental students and practitioners toward NIHL in Saudi Arabia.	Cross‐sectional study	Dental students and practitioners (n = 252)		Majority (n = 174; 69%) dental students and practitioners scored weak on knowledge (4.48, SD = 2.33) more that attitude and practices respectively, attitude (66.3, SD = 7.62); (15.6, SD = 5.97).
Assessment of occupational noise‐related hearing impairment among dental health personnel	Al‐Omoush et al. (2020) [26] Jordan	To examine hearing thresholds associated with sound levels from equipment among dental personnel	Cross‐sectional study	The test groups consisted of 39 dentists, 28 dental technicians, 23 dental assistants, and 92 fifth‐year dental students. The control group consisted of 62 third‐year dental students.	Hearing thresholds of the left ear showed a deterioration that was associated with duration of noise exposure and age. Student groups' hearing thresholds were not significantly affected by noise levels emitted due to their limited exposure duration, and their findings were similar to the control group's findings.
Increased signs of noise‐induced hearing loss in dental students: a multilevel approach	Fuentes‐López et al. (2022) [15] Chile	To determine a possible association between noise exposure from dental equipment and early signs of noise‐induced hearing loss (NIHL) in dental students.	Cross‐sectional study	Dental Students and non‐dental students/control group non‐dental students 102 dental students and 251 controls	Non‐exposed group notch prevalence was less when compared to the dental students at 4000 Hz and 6000 Hz
Auditory effects of recreational and occupational noise exposure among dental students: a cross‐sectional study	Fuentes‐López et al. (2021) [27] Chile	The study aimed to determine the auditory effects of noise exposure from recreational and occupational sources among dentistry students	Cross‐sectional study	Undergraduate students doing clinical practice with dental instruments were invited to participate. The control group was made up of students from other health‐related undergraduate programs. 42 dental students and 78 health science students	No significant differences in auditory thresholds between groups were found. The control group had a significantly higher prevalence of a notch at 4 kHz than the group exposed to noise. The significant differences were attributed to recreational noise exposure.
Assessment of knowledge, attitude and practice towards dental environment noise among dental students	Keerthana and Khandelwal (2021) [28] India	To assess the knowledge, attitude, and practice towards dental environment noise among dental students	Cross‐sectional study	Dental students (n = 100)		Out of 100 participants, male (44%) and female (56%). About the majority of 77% were aware of the high levels of noise in dentistry, and 23% were not.
Clinical dental noise and its association with the hearing thresholds of New Zealand dental students and clinical staff	Ma et al. (2018) [29] New Zealand	Aim of study: the aim of this study was to investigate and compare the hearing thresholds of dental undergraduate students and clinical staff members	Cross‐sectional study	A total of 125 undergraduate students and 14 staff members	No statistically significant differences were observed in the mean hearing thresholds of undergraduate students in years two, three, four, and five at all frequencies examined. Clinical staff had significantly higher hearing thresholds than year‐two students at all frequencies except for 4.0 kHz. Combined data from all groups found no sex differences in mean hearing threshold, but higher mean hearing thresholds for the right ear were observed at 0.5, 1.0, and 2.0 kHz
Early detection of hearing loss among IIUM KUATAN dental students	Rahman and Alisaputri (2019) [30] Malaysia	To compare the hearing thresholds and otoacoustic emissions between dental students and non‐dental students in IIUM Kuantan.	Cross‐sectional study	Population description: 15 dental students and 15 normal hearing non‐dental students, forming study and control groups	There is no significant difference in threshold between the groups across the frequencies (p > 0.05); however, the study group shows slightly higher thresholds at 3000, 4000, and 14,000 Hz. The pattern of NIHL notch can be seen in the DPOAEs of the study group, even though the threshold is still within the normal hearing range, suggesting that early signs of NIHL among dental students can be detected by DPOAE
Hearing loss associated with long‐term exposure to high‐speed dental handpieces	Theodoroff et al. (2015) [31] United States	The purpose of this study was to record and compare audiometric pure tone thresholds of dental clinicians (DCs), dental professionals (DPs), and dental students (DSs); determine the percentage of these groups who use hearing protection devices while at work in the clinic; and measure the sound intensities generated by a few representative high‐speed handpieces while they are being used on patients	Cross‐sectional study	Dental students = 8 Dental clinicians = 16 Dental practitioners = 13	The findings showed that DCs who regularly used high‐speed handpieces had worse hearing than did members of the other study groups. These results indicate that the implementation of protective strategies should help to reduce the prevalence of occupational hearing loss among DCs.

Eight (n = 8) studies reported on the risks of NIHL among the students. The risks were seemingly higher among senior dental students than first‐year students. In New Zealand, a study comparing noise levels among students and dental practitioners, dental practitioners had higher hearing thresholds than the students, thus reflecting increased risk for NIHL among practitioners as they had more years of noise exposure. In Chile and Malaysia, non‐dental students were found to have a lower noise notch prevalence in comparison to dental students. Dental clinicians who used high‐speed handpieces were also found to be at a higher risk than students and practitioners who had not used high‐speed handpieces.

Only four articles reported on NIHL awareness among the students. In the UAE and Saudi Arabia, it was found that the students lacked awareness and knowledge. Another study in Saudi Arabia assessing knowledge, attitude, and practices of NIHL among students and practitioners (n = 252) found that, in addition to the 69% of participants who reported weak knowledge, the knowledge domain was lower (4.48, SD = 5.97) than the attitude (66.3, SD = 7.62) and practice (15.6, SD = 5.97) domains. Finally, only one study from India reported on high numbers (77%) of students being aware of high levels of noise in dentist's office.

4. Discussion

The study aimed to ascertain the risks and awareness of NIHL among dental students globally, with the hope of informing the development of an awareness program during clinical training of dental students. In addition, to align with safe listening guidelines as outlined by the World Health Organization [9], which are geared towards hearing loss prevention for the young adult population group. Although our literature search was wide, 11 studies out of the 69 were relevant to the study aim, and one was excluded at a late stage as the full article was not written in English; thus, only 10 were analyzed to address the study objectives. The studies drawn represented seven regions of the world (UAE, Jordan, India, New Zealand, Malaysia, and the United States of America) where studies were conducted, and all the studies had a cross‐sectional design. It must be noted that studies from the Sub‐Saharan African region were not found, raising concerns around knowledge gaps in the region. However, findings from other regions could benefit regions not represented.

The common audiological symptoms associated with NIHL among dental professionals include tinnitus, a sense of fullness, and otalgia [12]. In addition to the commonly reported symptoms associated with hearing loss, our study findings suggested that dental practitioners had more elevated hearing thresholds than dental students, showing increased risk for NIHL. This was attributed to their many years of cumulative noise exposure, which students did not have. Risk associated with cumulative noise exposure is echoed by Hartland et al. [12], indicating that years of experience were a risk factor for NIHL in dental professionals. Other studies reported that senior dental students were at a higher risk than students in the lower levels of study, for example, first‐year dental students [32, 33]. Duration and frequency of noise exposure, reported as years of experience, in various dentistry settings, could be a contributing factor associated with the risk for NIHL. Consequently, not accounting for the duration of noise exposure (in years) could have negative implications. Therefore, further studies investigating the actual years of experience for dental students and professionals, to account for the risk associated with NIHL, are necessary. The fact that NIHL is linked to a disabling hearing impairment, with implications on the individual's QoL, later in life, requires further research.

Although most research studies have cited that noise exposure levels from the dental equipment used are risks for NIHL, the noise exposure levels of this equipment were below 85 dB(A). There were various pieces of equipment used during dental procedures that emit different types of noise at different intensity levels, but the high‐speed handpieces were reported to emit an irritating type of noise, which was associated with tinnitus after use [34]. Rogers [34] further reported that the high‐speed dental handpieces produced noise (69.4–77 dBA) below the 85 dB(A) [34]. Other authors also argued that high‐speed dental handpiece technology has not changed since the 1960s, yet it was the most commonly used piece of dental equipment, with concerning noise exposure levels and peaks (107 dBA) [35]. The variability of the sounds emitted by the dental instruments may be attributed to dental procedures and could play a significant role in predisposing dental students and practitioners to NIHL risk, but accounting for cumulative exposure for these population groups requires empirical evidence [36]. Therefore, considering the low exposure levels and reduced intervals, we are suggesting that sound‐induced hearing loss (instead of noise) may be a suitable term that could be used to inclusively describe the hearing functions of dental students and professionals. Hearing loss interventions aligned with sound‐induced hearing loss could provide prevention solutions for dental students and professionals.

Awareness of hearing loss among young people is critical to encourage behavior modifications geared towards preventing early hearing loss diagnosis. One study reported that 77% of dental students were aware of NIHL. Furthermore, some studies indicated that students were knowledgeable about the risks associated with NIHL, but for the most part, students presented with poor knowledge and awareness around NIHL. This is no surprise as occupational noise exposure in the dental clinic is currently not part of the dental curriculum [4, 37]. Although the risk associated with NIHL has largely been reported among dental clinicians rather than dental students, the study highlights a potential gap in knowledge for undergraduate training regarding strategies for the early protection of hearing. Furthermore, formulating clear hearing loss strategies in clinical settings [38] could bode well for behavioral adoption geared toward NIHL prevention for dental students.

5. Implications

Increased risks for NIHL, associated with duration and level of noise exposure, were common. Although dental students presented with early signs of hearing loss (noise‐notch evident on audiograms with normal hearing), the significant hearing deterioration in the high frequencies, which was reported for the qualified dental professionals' hearing thresholds, was worrying. The double impact of recreational and noise exposures presents an overall hearing deterioration that cannot be ignored, especially for dental students. Since the use of high‐speed handpieces was common, various types of those and their actual noise exposure levels should be correctly documented to accurately apportion their contribution to hearing loss. Although NIHL is a common term used, the benefits of reimagining the term to sound‐induced hearing loss (SINHL) to incorporate profession‐specific sound emissions during dental procedures may help design awareness campaigns for this population group and their various clinical contexts.

6. Strengths and Limitations

The incorporation of the two independent reviewers throughout the coding process strengthened the study's quality assurance and reliability. The review search period was stretched to cover 10 years and to provide a global overview, with the hope of including more studies. Nonetheless, only 10 studies met the inclusion criteria and were analyzed, but due to the small sample size, the study results has limited representation. However, the current review provided us with insightful information on the extent of NHIL and illuminated the gaps that need to be addressed.

7. Conclusion

The review findings suggest that the level of exposure to noise from dental equipment plays a significant role in predisposing dental students and practitioners to NIHL. Nevertheless, there is limited evidence from studies that target undergraduate students during clinical training to raise awareness about the risks associated with NIHL. Although there appear to be minimal risks among dental students, accounting for accurate noise exposure levels from all equipment used during clinical training is necessary to inform context‐specific management strategies toward NIHL prevention. Poor knowledge and awareness of the risks associated with NIHL were apparent among dental students; therefore, education and training programs geared to raise awareness for NIHL prevention among students are imperative, and the need for targeted research is necessary to promote the implementation of evidence‐based interventions on awareness towards NIHL prevention, for undergraduate programs in South Africa [4]. Furthermore, the fact that no studies representing the African continent were identified indicates a possible gap in knowledge around awareness of the risks of NIHL and prevention strategies in the continent's dental training institutions. Further research could explore safe listening behavior approaches for hearing loss prevention, and their integration into education and training programs for dental students as part of their undergraduate studies.

Author Contributions

Both authors contributed equally to the writing of the manuscript. All authors have read the final version of the manuscript. Liepollo Ntlhakana had full access to all of the data in the study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis.

Funding

The authors have nothing to report.

Conflicts of Interest

The authors declare no conflicts of interest.

Transparency Statement

Liepollo Ntlhakana affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

Data Availability Statement

The data for this scoping review consists of published studies retrieved from PubMed, CINAHL, ProQuest, Scopus, Web of Science, and EBSCO Host databases. The full search strategy, including databases, search terms, and inclusion/exclusion criteria, is provided in the manuscript and supplementary materials. No new primary data were collected; all included sources are publicly available.