AAPD use of nitrous oxide for pediatric dental patients (2023 revision): 30 to 40% usually does it, 50% is the ceiling, and 100% oxygen for 5 minutes at the end

What it says#

Use of Nitrous Oxide for Pediatric Dental Patients is an eight-page best practice in the Reference Manual of Pediatric Dentistry, developed by the Council on Clinical Affairs, adopted in 2005, last revised in 2018 and carrying a latest revision date of 2023. The revision rests on a PubMed search from January 1, 2012 in humans aged birth to 18 years that returned 288 articles, with expert and consensus opinion where the data were insufficient. The AAPD's framing is that nitrous oxide and oxygen inhalation is a safe and effective technique to reduce anxiety, produce analgesia, and enhance communication, and that parents prefer it to advanced behavior guidance techniques such as restraint and general anesthesia.

The definition matters for what follows. Analgesia and anxiolysis means a single agent at a nitrous oxide concentration of less than 50%, with or without local anesthesia. In that state the patient's response to verbal commands and protective reflexes remain unchanged, and preprocedural mobility returns after the gas is stopped. Onset and recovery are rapid, 2 to 3 minutes. Nitrous oxide is the weakest of the inhalation agents, with a minimum alveolar concentration value of 105; it is transported as free gas, does not combine with hemoglobin, does not undergo biotransformation, and is eliminated through the lungs.

Candidate selection is stated in ASA terms. Patients in ASA Physical Status Classification I and II are considered appropriate candidates. Children in ASA Class III, and those with special health care needs, anatomic airway abnormalities, or moderate to severe tonsillar hypertrophy, require additional and individual consideration. Success depends on acceptance of the nasal hood, nasal breathing and psychological reassurance; a child crying uncontrollably receives a diminished inspired concentration. Asthma is explicitly not a contraindication, and the document argues that reducing stress may lower the risk of an attack. Because nitrous oxide inflates air-filled spaces, patients with bowel obstruction or raised intraocular pressure, and those who have recently had retinal surgery, craniotomy or correction of intestinal obstruction, are not candidates. The most common adverse effects, nausea and vomiting, occur in 0.5 to 1.2% of patients, and fasting is not required.

The recommendations name five indications: a fearful or anxious patient; certain patients with muscular tone disorders prone to unintentional movement; a patient whose strong or hypersensitive gag reflex interferes with care; a patient for whom profound local anesthesia or analgesia cannot be obtained; and a cooperative child undergoing a lengthy procedure who would benefit from relief of treatment fatigue. Contraindications may include chronic obstructive pulmonary diseases; current upper respiratory tract infections such as cold, cough or tonsillitis, sinusitis, or other conditions such as seasonal allergies that inhibit nasal breathing; recent middle ear disturbance or infection; ear, nose or throat operations within 14 days; raised intraocular pressure such as glaucoma, and up to 3 months after retinal surgery; severe emotional disturbances or drug-related dependencies; the first trimester of pregnancy; treatment with bleomycin sulfate; and untreated cobalamin, that is vitamin B12, deficiency.

The technique section is where the numbers live. A flow rate of 5 to 7 L/min is generally acceptable for older children and adult patients, while 3- to 4-year-old patients typically require 3 to 5 L/min, adjusted by watching the reservoir bag, which should pulsate gently and be neither over-inflated nor under-inflated. Administration is by standard titration, which is 100% oxygen for 1 to 2 minutes followed by titration of nitrous oxide in 10% intervals, or by rapid induction, a fixed dose without titration. Administration of 30 to 40% nitrous oxide usually achieves analgesia and anxiolysis. The concentration may be decreased during minor procedures such as restorations and increased during more stimulating ones such as extraction or injection of local anesthetic. It should not routinely exceed 50%, to decrease the incidence of adverse events; if it exceeds 60%, patients may experience ataxia, giddiness, dysphoria, increased sleepiness and delirium, and become uncomfortable and uncooperative. Studies of greater than 50% did not always show more adverse reactions, but neither did they produce better behavior scores during restorative treatment. Flow-meter concentrations vary significantly from end-expired alveolar concentrations, which are what produce the clinical effect, so talking and mouth breathing are kept to a minimum.

Monitoring is clinical, not instrumented. Continuous clinical observation must be performed during any dental procedure involving nitrous oxide and oxygen, and the document names responsiveness, color, and respiratory rate and rhythm. If any other pharmacologic agent is used in addition, such as chloral hydrate, a benzodiazepine or an opioid, or if concentrations above 50% are maintained, the likelihood of a deeper sedative effect increases, and monitoring should be tailored to the actual, not the intended, response.

Recovery and the record are specified. Once the nitrous oxide flow is terminated, 100% oxygen is administered for at least 5 minutes until the patient has returned to pretreatment status, extended for patients who experience postoperative nausea and vomiting, and the patient must return to pretreatment responsiveness before discharge. Informed consent from the parent is documented before administration, and the record should carry the indication, the dosage as percent or flow rate of gases, the duration of the procedure, and the posttreatment oxygenation procedure.

The equipment floor is equally specific. Inhalation equipment must be able to deliver 100%, and never less than 30%, oxygen at a flow rate appropriate to the child's size, and must have a fail-safe that shuts off nitrous oxide when oxygen delivery falls below an established minimum such as 2.5 to 3.0 L/min. It must have an emergency air inlet, a quick connection for positive pressure and oxygen flush, and an effective scavenging system. Training and certification in basic life support are required for all clinical personnel. An emergency cart must be readily accessible, with equipment for children of all ages, and a positive pressure oxygen delivery system capable of more than 90% oxygen at 10 L/min for at least 60 minutes, a 650 L E cylinder, must be available; a self-inflating bag valve mask is run at 15 L/min. Where state law mandates equipment and facilities, those statutes supersede these recommendations.

Who it applies to#

Any dentist who runs nitrous oxide on children, in a pediatric or a general office, plus the assistant who sets the flow and the hygienist who may be in the room. The document is written for analgesia and anxiolysis with a single agent below 50%, and it says plainly that the practitioner is responsible for managing the complications of both the intended response and a deeper level of sedation.

It does not cover moderate or deep sedation, which the AAPD and the American Academy of Pediatrics handle in their joint monitoring guideline, and it defers to state law on equipment, facilities and calibration. Occupational exposure is treated briefly and handed off to the AAPD's separate policy on minimizing occupational health hazards, which notes that NIOSH published a 1977 recommended exposure limit of 25 ppm as a time-weighted average, later published a technical report aimed at limiting dental exposure to 50 ppm, and that the American Conference of Governmental Industrial Hygienists set a threshold limit value of 50 ppm in 1986, while OSHA has not established a permissible exposure limit for nitrous oxide in health care.

What changed#

The previous revision was 2018. The 2023 text carries an expanded treatment of metabolic concerns that a general dentist should know about: nitrous oxide exposure has been linked to irreversible inactivation of cobalamin, so patients with untreated vitamin B12 deficiency are not candidates, and exposure can raise plasma homocysteine in patients with certain MTHFR gene variants such as C677T and A1298C. The document reports one article describing the death of a child with previously undiagnosed MTHFR deficiency after two surgeries four days apart using 0.75% halothane and 60% nitrous oxide, notes that reports do not agree and that short exposures appear unlikely to be significant, and recommends that patients with severe MTHFR deficiency may benefit from consultation with a geneticist or anesthesiologist. The occupational literature is characterized as scarce and inconsistent, with reduced fertility and spontaneous abortion risks not significantly elevated in offices using scavenging systems. This entry did not compare the 2018 and 2023 texts line by line.

Where the source is#

The link under the title is the AAPD's page for the best practice, which opens the Reference Manual PDF, Use of Nitrous Oxide for Pediatric Dental Patients, latest revision 2023, printed at pages 415 to 422 of the 2025 manual; the How to Cite line on the document is the citation above. The AAPD web page currently lists the chapter under the 2026-2027 edition of the Reference Manual, so the page numbers here are from the PDF the site serves today. The inventory for this directory pointed at the PubMed record for the 2013 version; the current chapter is what sits at the AAPD link, and that is what this entry reports. The occupational exposure figures come from the AAPD's separate Policy on Minimizing Occupational Health Hazards Associated with Nitrous Oxide, also revised in 2023, downloaded and read for this entry. All three AAPD PDFs are free to read and download, and copyrighted by the Academy.