By Zee Maq

Why Are Dentists At An Increased Risk Of Hearing Loss And Tinnitus?

A study was conducted on a group of dentists to assess the health impacts of the sound emitted by their medical equipment. The study focused on qualifying how many practicing dentists are at risk of medical conditions like NIHL (noise infused hearing loss) and tinnitus. Dentists At An Increased Risk Of Hearing Loss And Tinnitus and we will show you why.

The Main Focus

For decades now, audiologists have been carefully studying dentists as they can develop medical conditions like tinnitus and NIHL while working with their professional equipment. The noise emitted from their equipment, namely their handpieces and suction apparatus, puts them at risk.

While several smaller studies conducted in the past found and presented mixed results, they encouraged more research on the topic. The OSHA (occupational safety and health administration) quantifies the level of sound which should not be exceeded within the workplace. While some studies have noted that the OSHA standards are followed in a number of dental clinics, most clinics exceed these limits because of their equipment.

For reference, here are some studies on hearing loss.

  • One study which focused on the handpieces used by the dentists found that the high-speed handpieces can produce noise of up to 87 dBA, which is over the standard limit suggested by OSHA guidelines.
  • Another study found that the handpiece produces over 102dB SPL sound, which is a hazardous sound pressure level.

Usually, newer electrically operated equipment and ones that do not operate at their full potential don’t emit dangerously high levels of noise. Some studies have also focused on the number of times dentists are exposed to sound while they’re working.

While newer handpieces are quieter due to technological advancements, the level of sound they produce is still concerning for the health of the dentists and healthcare professionals using them regularly for elongated periods.

In addition to evaluating the noise emitted by dentists’ equipment, studies have also tested the hearing threshold of dentists compared to physicians. In these tests, physicians were usually found to have a better hearing threshold compared to the practicing dentists. Even a study conducted on dental students suggested that students typically suffer from TTS (Temporary Threshold Shift) after using handpieces in the laboratory. Unfortunately, repeated TTS can lead to a permanent threshold shift.

Tests comparing the hearing health of different types of dentists have also been conducted. For example, researchers found that dentists who use high-speed handpieces usually have a poorer hearing threshold compared to dentists who never used those handpieces. This suggests that the use of noisy equipment leads to a permanent decline in hearing ability.

Tinnitus in Dentists

Although more studies should be conducted to explore dentists’ hearing health, there are some studies that show specific results. A survey conducted in South Africa found that over 31% of all practicing dentists in South Africa had tinnitus. A study in the UAE found that over 21% suffered from hearing loss, and 37% accepted that they suffer from tinnitus. However, there are no such reports regarding this issue in the US; there is almost no progress being made to ensure the hearing health and safety of American dentists.

These alarming results suggest that there is a need to increase the NIHL and tinnitus testing of dentists, especially given the new and improved equipment. Also, all the medical equipment that they use in their clinics needs to be tested and compared against each other in order to reach some conclusive results. The study, which is described below, worked to address these questions by measuring the noise levels of standard equipment being used in dental clinics. This is in combination with a survey that accessed the extension of NIHL and tinnitus exposure of dentists. Real practicing dentists were involved in the study to reach reliable results.

Equipment Used

Individual Handpieces

Individual handpieces’ noise levels were tested when a licensed dental professional used them. A mannequin was used to make the setup like a dental office. The sound level was recorded whenever the handpiece was used on the teeth of the mannequin. The teeth used were the same as the ones used to train dental students in medical colleges. 8 different usage scenarios were set up in order to measure the sound levels coming out of the handpieces.

Similarly, a high sound producing suction apparatus was also assessed for sound level. This apparatus was also used in different settings to collect valuable research data and to see how it creates varying levels of sound under different usage scenarios.

All of the measurements were made and compiled according to the common usage scenario of the dental equipment. 20 second sound samples were collected and were compared against each other for reference.

Sound Level Measurements In Dental Operatory

Dental device sound measurements were also made during dental student training in the laboratory. During the laboratory exam, over 60 headpieces were running in full capacity under the same operatory. They were simulating the environment inside a busy dental practice.

In this examination, the operatory was sampled from 12 different locations to get the average amount of sound being produced by 60 handpieces running simultaneously. These samples also included recordings from near the level of the students when they had a running handpiece in their hands.

A Survey Was Run on the Oklahoma Dentists

In this study, a questionnaire containing two main parts was emailed to the members of the Oklahoma Dental Association (ODA). The survey asked them to fill the questionnaire with information from their personal experiences. The questionnaire was specifically designed to do the following two things:

  • Assess the exposure of those dentists to different sound ranges (mostly the ranges being produced by the equipment mentioned above).
  • Assess their exposure to NIHL and tinnitus.

The first part of the survey asked the dentists for their age, gender, and the number of years they’ve been practicing in the dental field. The second part of the survey asked them if they’ve ever been diagnosed with hearing loss or tinnitus.

Since more information was needed regarding tinnitus, the survey also asks a few more questions to the people who reported suffering from tinnitus. These questions were asked to assess the severity and frequency of tinnitus they experienced. The survey also asked them how long they were exposed to noisy dental equipment and if they used some sort of protective gear to keep themselves safe from this noise.

Dentists At An Increased Risk Of Hearing Loss And Tinnitus.

The Results

Measurements made in the operatory when suction apparatus was used alone or with a handpiece suggested that a dangerous level of noise was being made by the equipment. The data collected from the ODA dentists suggested that they suffered from hearing loss according to the national average. Also, more dentists reported their exposure to tinnitus than was expected.

In Individual Handpieces

When single working handpieces were tested for sound levels, they usually made sounds of up to 70 to 83 dBA, which is below the maximum limit suggested by NIOSH (the recommended maximum 8-hour limit is 85 dBA). However, when the handpiece was used in combination with obstructed and unobstructed suction, the noise emitted exceeded the 85 dBA limit. This might be the reason for the loss of hearing in the dentists with more exposure to this apparatus.

In the Training Operatory

The data and sound samples collected from various simultaneously running handpieces in a single operatory did not exceed the NIOSH suggested maximum limit. And, since training mannequins were being used by the trainees, in this case, no suction apparatus was used along with the handpieces in the large operatory.

The Oklahoma Dentists’ Survey

Three hundred ninety-five dentists of ODA were contacted and were sent the emails, including questionnaires. Of those, 144 surveys were completed and returned. All of the further analysis was conducted using these filled questionnaires.

Demographics of the Research

The mean age of the ODA dentists that responded was 57.5 years, and the range was between 76 and 35 years old. They had an average of 27.2 years of experience in the field. A majority of the participants were males which are in line with the overall percentage of males and females in the dentistry industry in the US.

Hearing Loss

1 in every 4 respondents reported a loss of hearing ability. However, keep in mind that around half of them were over 60 years of age. The hearing loss was found to be equal, or even slightly lower than, the national average when the studies were compared to the suggested national average of hearing loss per decade of life.

Over 31% of the dentists believed that their dentistry career had caused a decrease in their hearing threshold.

Tinnitus

Some tinnitus was reported by 1 in every 3 respondents. Additionally, 1 in every 3 of the dentists reporting tinnitus mentioned that their tinnitus problem is very bothersome.

In contrast to the hearing loss measurements, which coincided with the national average, tinnitus measurements exceeded the national average. Some dentists even suggested that they find their tinnitus to be worsened by the end of their workday. One quarter believed that their tinnitus problem was because of their dental profession, while over half of them weren’t sure about this.

Dentists At An Increased Risk Of Hearing Loss And Tinnitus

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Understanding Hearing protection

REFERENCES
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5227015/
  • Setcos JC, Mahyuddin A. Noise levels encountered in dental clinical and laboratory practice. Int J Prosthodont. 1998;11:150–7.
  • Brusis T, Hilger R, Niggeloh R, Huedepohl J, Thiesen KW. Are professional dental health care workers (dentists, dental technicians, assistants) in danger of noise-induced hearing loss? Laryngorhinootologie. 2008;87:335–40. 
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