General dental practitioners and hearing impairment

Abstract

Objective

Hearing impairment (HI) remains a problem among dentists Hearing loss at speech frequencies was recently reported among dentists and dental hygienists. This study aimed to investigate prevalence and factors associated with perceived HI among dentists.

Methods

In 2009–2010, 100 general dental practitioners (GDPs) and 115 general (medical) practitioners (GPs) (mean ages, 43.7 and 44.4 years) from Rome (Italy), who commenced practice ≥10 years ago, were interviewed on a series of occupation- and recreation-related HI risk factors and on HI-associated symptoms (tinnitus, sensation of fullness, hypoacusis). Prevalence of presumptive HI (≥1 symptom perceived during workdays and weekends) was assessed and factors associated with presumptive HI were investigated.

Results

Prevalence was 30.0% (95% confidence interval, 21.0–39.0%) and 14.8% (95% confidence interval, 8.3–21.3%) among GDPs and GPs, respectively. Occupation (GDP vs. GP), family history of hypoacusis, hypertension, ear diseases and smoking were significantly associated with presumptive HI. Within GDPs alone, significant associations were found for frequent use of ultrasonic scalers, use of dental turbines aged ≥ 1 year and prosthodontics as prevalent specialty.

Conclusions

GDPs experienced HI risk than GPs. Such a risk was not generalized to all dentists, but was specific for those who frequently used noisy equipment (aged turbines, ultrasonic scalers) during their daily practice.

Clinical significance

GDPs with 10 or more years of practice who routinely use potentially noisy equipment, could be at risk of HI. In order to prevent such condition, daily maintenance and periodical replacement of dental instruments is recommended.

Introduction

Environmental noise is responsible for hearing impairment (HI). Daily exposure for 8 hours to noise levels ≥85 A-weighted decibels (dB(A) is associated with permanent hearing loss.1, 2 The A-weighting system (dB(A)) approximates the frequency response of our hearing system, weighting lower frequencies as less important than mid- and higher frequencies). Within healthcare settings, high environmental noise in hospitals may be responsible for abnormal hearing among healthcare workers,3, 4 while the orthopaedic staff experienced the highest prevalence of hearing-associated problems, due to high-powered tools in orthopaedic theatres.5, 6, 7, 8, 9, 10

In the 1960s, environmental noise produced in dental healthcare settings was considered responsible for HI in the dental staff.11, 12, 13 However in almost all previous studies dentists did not experience higher HI risk than the general population.14, 15, 16, 17, 18 This success was probably due to the technological improvement of dental equipment which considerably reduced the degree of environmental noise.19, 20, 21, 22 Nowadays, the noise levels generated by suction tubes, turbines, ultrasonic scalers and micromotor hand-pieces are generally below the HI threshold of 85 dB(A), irrespectively of brands, type of material cut, type of bur, etc.23, 24, 25 Thus, excluding peculiar situations, such as occasional peaks during burring²¹ or children's crying episodes,²² the environmental noise during daily practice could be considered reasonably safe.

Nevertheless, the problem of HI among dental healthcare workers became relevant once again in recent years. Indeed, hearing loss at speech frequencies was reported among dental hygienists²⁶ and dentists.27, 28 In addition, three questionnaire-based surveys reported that 11.3% dentists from Thailand had hearing problems or were not sure about their hearing capacity,²⁹ 19.6% from Belgium had auditory disorders²⁷ and 5% from United Arab Emirates had hearing problems.³⁰ We hypothesized that the revival of this problem was due to the prevalent specialty practiced by general dental practitioners (GDPs) and to the use of aged or worn instruments. Indeed, environmental noise produced by worn or extremely aged instruments is high: levels > 85 dB(A) can be produced during everyday practice and turbines become louder after one year of use-sterilization cycles if they are not properly maintained.21, 22, 31, 32, 33, 34 In addition, differences by 10–20% in environmental noise levels are reported between units according to the prevalent specialty.²⁰ Thus, the aim of this study was to investigate prevalence and factors associated with perceived HI among GDPs.