Purpose: The purpose of the study was to evaluate the success of procedural conscious sedation using inhaled equimolar nitrous oxide-oxygen (NOIS-EMONO) in patients undergoing routine dental and oral surgery procedures in a Swiss university hospital setting.

Materials and methods: The authors conducted a retrospective cohort study of patients that underwent NOIS-supported procedures between 2018 and 2022 at the oral surgery department of the University Hospital of Geneva (HUG), Switzerland. The primary outcome was the measurement of the procedure's success and efficacy as defined by the European Society of Anesthesiology. Secondary objectives included the analysis of the types of treatments performed, their indications, patient behavior, and the patient-clinician satisfaction score.

Results: 55 patients were included in the study; 85% underwent surgical procedures, and the remaining 15% underwent restorative and preventive procedures. The overall treatment success rate was 98.2% and 97.9% for surgically treated patients. Out of the patients, 62% appeared relaxed, calm, and serene, while 16% expressed pain or fear during the procedure. Infiltrative administration of local anesthesia caused stress in 22% of patients. This portion was significantly lower in sub-cohorts who received local topical anesthetics (0%) or a combination of systemic and local topical analgesics (7%). Patients (75%) and clinicians (91%) were satisfied with the procedure.

Conclusion: Inhaled equimolar nitrous oxide-oxygen procedural sedation used during dental procedures and oral surgery results in high treatment success and satisfaction rates. The administration of additional topical anesthetics helps to reduce the anxiety and stress related to infiltrative anesthesia. Further dedicated studies and prospective trials are needed to confirm these findings.