User:Sam5chat/Occupational safety and health

Healthcare and social assistance
 Occupational Exposures in Dentistry 

Dental professionals along with their team, encounter multiple exposures daily. These occupational exposures are detrimental to their health, especially when they are chronic in nature. [[File:HighVolumeSuction.jpg|thumb|Dental handpiece ( left) and high volume suction.

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 * Exposure to Noise: Any undesirable sound present in the working environment is referred to as Occupational Noise. According to OSHA, when working five days a week in any environment, the international standard of the eight-hour daily occupational exposure should not be greater than 85 dBA, and anything above this could cause noise-induced hearing loss. Hearing loss induced due to irreversible injury to the inner ear from chronic, cumulative exposure to loud sounds is called Noise-induced hearing loss (NIHL). Buzzing and ringing of ears also called tinnitus and dulled hearing are symptoms of NIHL. Several health problems arise due to overexposure to loud noises such as stress, disruption in sleep patterns, cardiovascular disorders, anxiety, fatigue, and depression. Dental professionals are exposed to noise generated by a wide variety of instruments like ultrasonic scalers, suction, and air rotor handpieces. The recommended maximum exposure limit to sound on an 8-hour workday is 85 dBA. In a study, unobstructed suction noise levels had a range of 75-79 dBA, while obstructed suction had a noise level of 96 dBA, and it was recommended that professionals should not have an exposure of more than 1 hour in such a workplace. High-intensity sounds form ultrasonic scalers range between 69-84 dBA within the safe 8-hour limit for occupational noise. Threshold shift, the reduction in hearing due to reduced sensitivity level of ears due to noise exposure, occurs due to the use of an ultrasonic scaler, and although this is found to last between 16 hours to almost 2 days, it could cause irreversible damage. In a study conducted in the Dental School of Prince of Songkla University, Thailand, noise annoyance in the dental clinic has been reported by 80% of dental students. The highest percentage of noise dose exposure is found in clinics for pediatric patients.




 * Exposure to Inhalational Anesthetics: Several inhalational anesthetic agents are used in dentistry nowadays like isoflurane, sevoflurane, desflurane, and halothane. But we are most concerned about gaseous sedative, Nitrous oxide. Long-term exposures to nitrous oxide may lead to adverse effects on human health such as infertility, neurologic disorders, blood disorders, and spontaneous abortion. Researchers believe that when operating rooms without proper ventilation systems have high non-scavenged gas exposures, the risk of spontaneous abortion increases. It is found that despite intact scavenging systems in dental clinics, sometimes nitrous oxide exposure exceeds the NIOSH recommended limit of 25 ppm by more than 40 times. NIOSH advises dental professionals to use additional ventilation or increase air circulation in the operating rooms to tackle the high N2O exposure.
 * Exposure to Elemental Mercury: The most likely source of exposure to elemental mercury for dental professionals is mercury release in dental amalgam restorations. Due to prolonged practice in the field of dentistry and working with amalgam there is a significant exposure to mercury among professionals. Inhalation of Hg leads to its absorption in the lungs and accumulation in kidneys, and evidence suggests that dental professionals have higher urinary mercury levels. About 84.9% of dental practitioners among those attending a health screening program in the annual ADA session in San Francisco, California were found to restore teeth with 1-200 dental amalgam restorations in a week, and about 4.2% did a minimum of 50 dental amalgam fillings in a week. Minute quantities of elemental mercury elevate the Hg concentrations in dental clinics, such that it poses threat to human health. Mercury vapors and elemental mercury remain in furniture, floors, clothes for years if not cleaned properly, and contribute to being a chronic source of exposure. The limit for elemental mercury vapor in workplaces is 0.05 mg/m^3 as recommended by OSHA, especially for workers working 40 hours in a week for 8 hours per day, and that for elemental mercury vapor in workplaces set by NIOSH is 0.05 mg/m^3 for a work shift of 10 hours. Inhaling elemental mercury vapors lead to serious health consequences in humans. Acute exposure to elevated levels to Hg leads to headaches, insomnia, irritability, memory loss, and slow sensory and motor nerve function along with depressed cognition, renal failure, chest pain, dyspnea, and impaired lung activity. Chronic exposures to elemental mercury lead to hypersalivation and erethism. Several studies show the risk of spontaneous abortions and birth defects in infants on elemental mercury exposure. Elemental mercury has a reference concentration of 0.0003 mg/ m^3, and when exposures are greater than this level, the possibility of harmful consequences to health increases.