Reducing the environmental impact of nitrous oxide in dentistry: a national quality improvement project.

Background Nitrous oxide (N2O), used in dentistry for inhalation sedation, is a greenhouse gas. Advice on how to mitigate the environmental harm in healthcare settings is not dental-specific.Aim The aim was to quantify the environmental impact of N2O used in UK dentistry, and make recommendations to reduce the environmental harm, while maintaining patient care.Method This study followed quality improvement project methodology. Following a pilot at the Eastman Dental Hospital in London, a national protocol was devised and advertised through the British Society of Paediatric Dentistry in 2022. Participating services audited the carbon footprint (measured in kilograms of carbon dioxide equivalent [kg CO2e]) of their sedation. Where possible, wastage was estimated.Results In total, 31 dental services across the UK returned data from 891 sedation appointments. The average carbon footprint administered per appointment was 28.62kg CO2e (range: 10.74-40.67). Wastage was estimated at 52 out of the 128 participating sites, with an average of 30% at sites using a central piped supply, and 4% at sites using individual cylinders.Conclusion N2O used in dentistry has a quantifiable impact on the environment. This study highlighted significant variations in wastage and clinical administration. Recommendations are made for dental services using N2O.