In the past, nitrous oxide, or laughing gas, was the prevailing means of painless dentistry. However, dentists now use alternative treatment methods that aren’t nitrous oxide. Why don’t dentists use nitrous oxide anymore?
This article explores laughing gas and why it is prevalent in sedation dentistry. It also explains why dentists don't use nitrous oxide anymore.
Nitrous oxide, also called laughing gas, is an odorless, colorless, and non-flammable gas. People call it laughing gas because it induces a state of euphoric feelings in patients who inhale it7. Although nitrous oxide is not a flammable gas, it supports combustion similarly to oxygen.
Nitrous oxide has anesthetic properties but isn’t as strong as other anesthetic compounds. It is the least potent inhalational anesthetic. To use nitrous oxide as an anesthetic, you must combine it with a more potent anesthetic. Nitrous oxide must reach 104% concentration in the lungs' alveoli before it renders the patient unconscious during surgical procedures.
Doctors use nitrous oxide for general anesthesia, procedural sedation, dental procedures, and pain relief. Its analgesic properties help reduce patients’ pain in emergency and obstetric units. However, they have to make a gas mixture using nitrous oxide. They often mix it with 50% oxygen.
Nitrous oxide doesn’t have muscle relaxant properties like other anesthetics. Apart from its medicinal applications, nitrous oxide has other uses. Some manufacturers use the gas as a propellant, while some use it as a recreational drug.
Dentists combine nitrous oxide with oxygen because it is an effective method of managing pain and dental anxiety. Dentists have used it as a local anesthetic since the second half of the 20th century, especially during the 1970s and 1980s.
Anxiety is one of the major problems dentists face when they are attending to their patients. It causes patients to miss their dental appointments or delays a dental procedure. To relieve anxiety and discomfort, dentists give them nitrogen oxide and oxygen.
For maximum effect, the nitrous gas should be inhaled directly. The inhaled gas helps dental patients endure unpleasant procedures by relieving pain and anxiety. Dentists usually use it on patients with special health care needs. They also use it on a cooperative child undergoing an extensive and time-consuming procedure.
Dentists use nitrous oxide for patients whose gag reflex interferes with dental examination and treatment. They use it on fearful patients. The intended effects of nitrous oxide are:
Nitrous oxide is popular in the dental department4 because it is easy to use and fast-acting. Dentists use it because no hangover effects are left when the patient wakes up. They recover quickly, and they do not need escorts. However, there are certain instances where they do not use nitrous oxide.
The dentist doesn’t use it for patients with chronic pulmonary diseases, a history of drug addiction, and women in their first trimester of pregnancy. Also, people with methylenetetrahydrofolate reductase deficiency can’t use N₂O.
Dentists worldwide no longer use nitrous oxide, also called laughing gas. Why don’t dentists use nitrous oxide anymore? They no longer use it because of the potential side effects on dental patients, dentists, and dental staff. Here is a list of why dentists don’t use nitrous oxide anymore:
The NO gas is dangerous to the people administrating and receiving it3. Studies on animals show that the anesthetic gas can cause reproductive health problems2. It can lead to fetus resorption, congenital disorders, and congenital disabilities.
Also, nitrous oxide is a harmful gas that can cause immense environmental damage. Once released into the atmosphere, it damages the ozone layer, accelerating global warming and climate change.
Although the contribution of medical nitrous oxide to the environment is low, it's a way for the medical field to protect the environment. That's why dentists don't use nitrous oxide anymore.
Dentists don’t use nitrous oxide anymore because nitrous oxide exposure causes tracheal injury1—the pressure in air-filled endotracheal cuffs increases during nitrous oxide sedation, leading to tracheal mucosal injuries. Researchers studied 65 people undergoing surgery with tracheal intubation for an hour. They discovered tracheal lesions on the anterior and posterior tracheal walls.
The wrong application of laughing gas can kill a patient. The incorrect application could be because of a technical error, lack of vigilance, and poor judgment. Pipeline flaws can kill people with hypoxia, as it reduces the levels of oxygen in the body tissues6.
Over the past ten years, research discovered the side effects of the pain-free experience offered by nitrous oxide. Dentists no longer use nitrous oxide because it increases the potential risks of postoperative infection and nausea and vomiting5 (PONV). Two large-scale research studies discovered this side effect.
The research was Enigma Ⅰ and Enigma Ⅱ. Enigma Ⅰ studied 2050 patients, and Enigma Ⅱ studied 7112 patients. These people were undergoing surgery for 2 hours and less under general anesthesia. A group had other forms of anesthesia, while others had nitrous oxide.
The study shows that the patients who used nitrous oxide experienced more nausea, vomiting, wound infection, and fever than those who didn’t. The researchers concluded that leukocyte DNA damage from nitrous oxide use might cause an increase in infection rate.
Dentists used laughing gas because it was an easy way to relieve the anxiety and fears of a patient. However, most dentists no longer use nitrous oxide because of its harmful effects on people. Now, they use sedatives and other methods to make procedures like tooth extractions easy for their patients.
Tu, H. N., Saidi, N., Lieutaud, T., Bensaid, S., Ménival, V., & Duvaldestin, P. (1999). Nitrous Oxide Increases Endotracheal Cuff Pressure and the Incidence of Tracheal Lesions in Anesthetized Patients. Anesthesia & Analgesia.
Rowland, A. S., Baird, D. D., Weinberg, C. R., Shore, D., Shy, C. M., & Wilcox, A. J. (1992). Reduced Fertility Among Women Employed as Dental Assistants Exposed to High Levels of Nitrous Oxide. The New England Journal of Medicine.
Ahlborg, G., Axelsson, G., & Bodin, L. (1996). Shift Work, Nitrous Oxide Exposure and Subfertility Among Swedish Midwives. International Journal of Epidemiology.
Mohan, R., Asir, V. D., S., Ebenezr, V., Dakir, A., B., & Jacob, J. (2015). Nitrous Oxide as a Conscious Sedative in Minor Oral Surgical Procedure. Journal of Pharmacy and Bioallied Sciences.
Rossaint, R., Coburn, M., & Jantzen, J. P. (2017). Should We Still Use Nitrous Oxide in Our Clinical Practice? No!. Türk anestezi ve reanimasyon dergisi.
Herff, H., Paal, P., Von Goedecke, A., Lindner, K. H., Keller, C., & Wenzel, V. (2007). Fatal Errors in Nitrous Oxide Delivery. Anaesthesia.
Knuf, K. (2022). Nitrous Oxide. StatPearls - NCBI Bookshelf.
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.
Fact Checked By:
Isabela Sedano, BEng.