Purpose. Equimolar oxygen-nitrous oxide mixture (EMONO) is considered as a reference for dental care in children. Completion of dental treatment has usually been used as a criterion to assess EMONO treatment.

However, other patient-reported outcomes are needed. We sought to assess the prevalence of complete therapeutic effects (analgesia and anxiolysis) experienced by children during dental care under EMONO and identifying associated factors.

A national prospective observational multicentric study was conducted between September 2018 and June 2020 in 13 French university hospitals. Participants were children between 3 and 15 years of age requiring dental care under EMONO.

Results. 677 children were analyzed. Anxiolysis and analgesia were experienced by a large majority of patients (86.5% and 79.0%, respectively, and 73% experienced both effects). Several factors were associated with both analgesia and anxiolysis effects: the presence of expected effects (no loss of judgment and slight decrease in level of consciousness), the absence of agitation and distress, a positive perception of EMONO and ethnicity.

Most patients benefit from the therapeutic effects (anxiolysis and analgesia) expected by EMONO during dental treatment. It is reassuring to observe that most sociodemographic characteristics and medical history do not seem to influence the effectiveness of care.

The study was registered at www.clinicaltrials.gov under the reference number NCT03453411.