Graduation Date

Spring 5-6-2023

Document Type


Degree Name

Doctor of Philosophy (PhD)


Environmental Health, Occupational Health, and Toxicology

First Advisor

John Lowe


Nitrous oxide (N2O) is frequently used in dental offices and is regarded as safe for patients getting dental work done. However, nitrous oxide exposure at work has been linked to harmful health outcomes like infertility and diseases of the liver, kidneys, and nervous system. Unfortunately, Saudi Arabia lacks an occupational safety and health regulatory body, which may influence dental professionals' safety. This is a serious problem because it puts dental professionals at risk of nitrous oxide exposure at work.

Exposure to nitrous oxide at work can have serious health consequences. Therefore, it is critical to evaluate dental professionals' occupational exposure to nitrous oxide in Saudi Arabia. A passive sampler from advanced chemical sensors was used to measure nitrous oxide occupational exposure levels in breathing zones to evaluate the potential health effects of nitrous oxide exposure among dental professionals at the King Saud University Dental Hospital. In the second part of the study, the researchers aimed to evaluate the possible health effects of nitrous oxide exposure on dental professionals in Saudi Arabia through a questionnaire survey.

The findings of the first part of this study revealed that 90.9% of participants were exposed to levels of nitrous oxide that exceeded the recommended levels set by the National Institute for Occupational Safety and Health (NIOSH) in U.S. Participants who use a scavenger unit were exposed to lower nitrous oxide concentrations (median = 45.6 ppm) than those who don't (median = 120.5 ppm), with a significant difference between the two groups (nitrous oxide concentration; p-value = 0.032). Dental assistants were exposed to lower nitrous oxide concentrations (median = 49.2 ppm) than dentists (median = 198 ppm), with a p-value of 0.001 indicating a significant difference between the two professions.

The second part of the study involved a questionnaire survey given to members of the SSPD. Most respondents use nitrous oxide between one and five hours per week, and 8% use it more than 20 hours per week. In the last five years, more than 50% of participants said their use of nitrous oxide has increased. However, only 37.6% of clinic participants had a scavenging system in place. The study also found that nitrous oxide use may be harmful to both male and female reproductive health, with 13.3% of female dentists reporting miscarriages within the first five years of using nitrous oxide and 7.2% of participants reporting unexplained fertility issues. Participants also mentioned several symptoms, including headache, lightheadedness, fatigue, and vertigo.

The results of our study highlight dental facilities' shortcomings and increase public awareness of the potential health hazards of nitrous oxide exposure at work. Policies and rules must be created to ensure the safe use of nitrous oxide in dental facilities to safeguard dental professionals from the harmful health effects of nitrous oxide exposure. To reduce their exposure, dental professionals must also receive adequate training on the use of nitrous oxide and protective equipment like scavenger units. Sampling should also be done to increase sample size and overall power to more accurately characterize groups of people who have similar exposures. Furthermore, it is important to establish laboratory studies to comprehend the various sampling techniques. Studies are also required to investigate any risks connected to nitrous oxide use in dental offices.


2023 Copyright, the authors

Available for download on Saturday, April 26, 2025