The use of nitrous oxide, commonly known as laughing gas, for sedation in dental procedures is a well-established practice, offering a safe and effective means of managing anxiety for both children and adults. However, recent research conducted by the University College London (UCL) Eastman Dental Institute highlights a significant but often overlooked aspect of its application: the substantial environmental impact associated with its use. The study reveals that nitrous oxide is not just a clinical tool but also a potent greenhouse gas with a global warming potential that far exceeds that of carbon dioxide, raising critical concerns about sustainability in dental care.
Inhalation sedation with nitrous oxide is frequently employed during routine dental treatments including fillings, crowns, and root canal therapies. This technique benefits from a wide safety margin and has been instrumental in improving patient experiences, particularly among young populations who may otherwise struggle with dental anxiety. Yet, despite these advantages, the greenhouse gas implications present a complex challenge. Nitrous oxide’s global warming potential is approximately 273 times greater than carbon dioxide, underscoring the urgent need to reevaluate its usage within the context of climate change mitigation.
The UCL research team conducted an extensive analysis of 891 inhalation sedation episodes across 31 dental services and 128 primary and secondary care sites throughout the UK. Their findings paint a vivid picture of variability both in nitrous oxide consumption and in consequent carbon emissions from nitrous oxide use. On average, a single sedation appointment was responsible for an estimated 28.6 kilograms of carbon dioxide equivalent emissions (kg CO₂e). To conceptualize this, one sedation appointment’s emissions equate roughly to driving a petrol car over 72 miles, which is considerably more than what many would anticipate for a short clinical procedure.
Perhaps even more striking is the wide disparity at the service level, where emissions for one week of nitrous oxide use ranged from as low as 38.9 kg CO₂e to an astonishing 1,849 kg CO₂e. The upper extreme of this range represents emissions equivalent to nearly 4,709 miles driven in a conventional petrol vehicle. Such variation illustrates how clinical practices and operational choices can dramatically influence the ecological footprint of dental sedation.
A key factor contributing to this variability concerns the method of nitrous oxide delivery. The majority of dental sites employed individual gas cylinders, whereas a smaller subset utilized centrally piped systems. Intriguingly, the sites with piped nitrous oxide demonstrated average wastage rates 30% higher than those using cylinders. Nevertheless, wastage was inconsistent across all types of supplies, signaling that both systemic inefficiencies and perhaps operator behavior play central roles in environmental impact.
Another technical aspect scrutinized was the flow rate of nitrous oxide administered during sedation. The analysis uncovered a broad spectrum of flow rates, ranging from as low as 1 litre per minute to as high as 13 litres per minute, without any clear correlation with patient age or procedural complexity. This lack of tailored dosing suggests that many patients might be receiving higher gas volumes than clinically necessary. Such excess does not enhance the sedation’s effectiveness or patient comfort but unequivocally increases environmental emissions, highlighting a significant opportunity for optimization.
Despite these concerns, the study confirmed the high clinical efficacy of inhalation sedation, with successful completion rates of dental procedures reaching 92% across the surveyed sites. Notably, children and young people constituted 83% of the patient cohort, emphasizing the essential role of nitrous oxide as sometimes the sole sedation option available for this vulnerable group. This dual imperative—to maintain patient care quality while reducing environmental harm—represents a delicate balance for dental professionals.
A specific practice scrutinized within the study was the use of inhalation sedation for acclimatisation visits. These visits involve simple, minimally invasive procedures aimed at gradually familiarizing children with dental environments and treatments, intending to foster positive experiences. While some practices routinely employed sedation during acclimatisation, the data revealed no meaningful differences in procedural success compared to services that did not use sedation for these preparatory visits. This finding calls into question the environmental justification for routine sedation in such cases.
Given the significant carbon footprint associated with nitrous oxide usage, the authors emphasize the pressing need for dental services to implement strategies that curtail gas wastage and emissions. Recommendations include rigorous auditing of nitrous oxide consumption, minimizing excessive flow rates, shortening administration times where feasible, and critically evaluating the necessity of sedation for acclimatisation procedures. Furthermore, the study underscores the potential benefits of standardizing sedation practices to reduce variability and improve environmental outcomes across the sector.
The researchers advocate for professional dental bodies to integrate environmental considerations into future sedation guidelines actively. By doing so, the profession can encourage the adoption of best practices that align clinical efficacy with sustainability goals. Moreover, ongoing research is essential to deepen understanding of nitrous oxide wastage mechanisms and optimal clinical administration protocols, fostering innovations that mitigate environmental impact without compromising patient care.
This pioneering UK-wide study serves as a crucial reminder that clinical tools once viewed solely through the lens of patient benefit must now also be evaluated for their ecological consequences. Bridging dental health care and environmental stewardship demands collaborative efforts among clinicians, administrators, policymakers, and researchers. By adopting evidence-based practices that minimize nitrous oxide emissions, the dental community can contribute meaningfully to broader climate action initiatives while continuing to serve patients’ needs effectively.
The findings present an important call to action. The dental profession, often celebrated for advances in patient comfort and procedural success, has an opportunity—and arguably a responsibility—to also lead in environmental sustainability. Strategies to reduce the carbon footprint of dental sedation can ultimately enhance the sector’s contribution to global efforts combating climate change, demonstrating that high-quality health care and environmental consciousness need not be mutually exclusive.
Subject of Research: Environmental impact of nitrous oxide use in dental sedation
Article Title: Quantifying the Carbon Footprint of Nitrous Oxide Sedation in UK Dentistry: A Multi-Site Analysis
News Publication Date: 2025
Web References: http://dx.doi.org/10.1038/s41415-025-9201-6; https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator
References: Lyne, A. et al., British Dental Journal, 2025
Keywords: Nitrous oxide, dental sedation, greenhouse gases, carbon footprint, climate change, inhalation sedation, dental anxiety, environmental impact, sustainability, dental practice, flow rate, gas wastage
