Nitrous oxide -oxygen conscious sedation (N2O- O2 sedation) is a commonly used technique in paediatric dentistry to manage anxiety and discomfort in patients undergoing dental procedures.This technique helps to reduce the physiological and psychological stress in anxious paediatric patients. Various benefits of using N2O- O2 sedation technique are its properties such as anxiolysis, mild analgesia, and amnesia.

Nevertheless, nitrous oxide poses a potential risk to clinical staff regularly administering inhalational sedation. There is substantiated evidence that prolonged exposure to nitrous oxide gas may result in hematological, reproductive, and neurological issues. Although the use of scavenging equipment, proper techniques, and well-ventilated surgical environments has notably reduced staff exposure levels, there remains some residual pollution within the surgical setting.

The traditional approach to N2O-O2 sedation involves the continuous administration of N2O- O2 throughout a dental procedure to ensure the ongoing cooperation of the patient. In the case of mildly to moderately anxious children, once profound local anesthesia has been established, it becomes possible to interrupt the continuous administration of N2O-O2 sedation while still effectively managing anxiety and maintaining desired behaviour. We assume that if behaviour issues related to local anesthetic administration alone have been successfully addressed, 100% oxygen may be administered, offering a potential means of reducing chronic exposure of the dental team to potentially hazardous levels of ambient nitrous oxide and to reduce the chance of over sedation to patient.

Hence, this study is planned to investigate the impact and sedation level achieved by interrupted N2O-O2 sedation administration, following the achievement of profound local anesthesia, on the physical, physiological, psychological parameters and behaviour of paediatric dental patients with mild to moderate anxiety during the rehabilitation of molars.