# Conscious Inhalation Sedation with Nitrous Oxide and Oxygen in Children: A Retrospective Study
## 4 Discussion
(2016) analyzed the efficacy and tolerability of N2O/O2 in a sample of 472 noncooperative pediatric patients (aged 4-17 years, but mainly in patients aged 4-6 years) who were unable to accept dental procedures because of dental anxiety and were treated with N2O conscious sedation as an alternative to general anesthesia and showed a success rate (i.e., optimal sedation to complete dental procedures) in more than 86% of children with a very low rate of side effects (2.5%) [35]. According to [PERSON] et al., who analyzed the success rate of sedation with N2O and O2 in dentistry in a systematic review and meta-analysis that included 19 articles (8 RCTs and 11 crossover studies), with a total of 1098 pediatric patients and 195 adults, the success rate of N2O/O2 administration was 91.9% (95% CI: 82.5-98.1%) [46]. The higher success rate in our study may be explained by the combination of conscious sedation and the use of insulating rubber, a stress-reducing agent used in children during dental treatment that promotes nasal breathing and thus better inhalation of the total dose of N2O administered. In a recent randomized, controlled trial conducted on a sample of 51 children (mean age 6.55 \(\pm\) 1.81 years), 21 of whom were treated with conscious sedation (9 with rubber dam and 12 with cotton roll isolation), [PERSON] et al. (2021) found that both Venham score and heart rate were lower in children treated with rubber dam and conscious sedation than in children treated with conscious sedation and cotton isolation only (_p_ < 0.05) [47]. Similar results were also shown in a recent study that evaluated data from 112 medical records of children (mean age: 6.1 \(\pm\) 1.8 years) who received restorative treatment under moderate sedation. After adjusting the regression model for sedation depth, sedation regimen, age, and sex, [PERSON] et al. (2022) reported better behavioral outcomes in patients treated with rubber dam compared with those treated with IsoVac, an innovative dental isolation treatment [48]. Placement of clamps without local or topical anesthesia, a procedure that has bothersome or even painful effects, is a potential barrier to appropriate treatment of children with dental anxiety. In our work, the behavioral approach and the first appointment for familiarization, during which the clinician explained the safe role of the rubber dam, helped to increase children's compliance during the first phase of dental treatment. In the patients in whom treatment was discontinued, the lack of relaxation was not due to the lack of effect of N2O/O2 but to poor inhalation of nitrous oxide caused by a significant lack of cooperation on the part of the children. Unlike other forms of sedation such as midazolam, N2O/O2 is inhaled by the patient, and a certain degree of cooperation is required for proper inhalation: a child who is screaming or yelling either receives no N2O/O2 at all or a very low dose that prevents his or her relaxation. This study has some limitations, mainly because of its retrospective study design and the lack of a control group. First, selection bias may have occurred because patients were selected without randomization. Second, DFA levels were not quantitatively determined in the children at baseline, so some degree of heterogeneity could not be excluded. Finally, nonpharmacological strategies were used in all patients before N2O/O2 sedation, but their effects on patient relaxation were not considered. Future prospective and randomized studies are needed to consider the exogenous and endogenous factors that may influence DFA and children's perception before and during dental treatment. Moreover, according to the recent study of [PERSON] and colleagues, who observed a certain level of children's attraction toward nitrous oxide in case of prolonged use [49], future studies should focus on this aspect and evaluate possible dependence effects with nitrous oxide prolonged use.