Background: Nitrous oxide (N2O) is used worldwide for analgesia and anesthesia. It is also used for recreational purposes by some people. N2O can have major side effects (myeloneuropathy, delusions, emphysema) when used to excess. In France, N2O is available as an equimolar mixture of oxygen and nitrous oxide (EMONO). Its substance use disorder potential is monitored by the French Monitoring Centre for Addiction (CEIP-A) network. Our objective is to provide an overview of the substance use disorder potential of N2O in general, and of EMONO in particular. Methods: This paper is based on a systematic review of the literature for case reports involving N2O use disorder and on CEIP-A network cases involving EMONO use disorder. We characterized use disorder in accordance with DSM-5 ( Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) criteria. Furthermore, we considered data relating to medical history, age, gender, and N2O consumption habits. Results: We identified 59 cases of N2O use disorder in the literature and 17 cases of EMONO use disorder from the CEIP-A network. More than 90% of the cases used N2O in larger quantities and for longer than intended. Conversely, more negative as opposed to positive cases have been documented regarding tolerance and failed attempts to reduce usage. Conclusions: A specific profile of substance use disorder starts to emerge from all the cases studied here. Furthermore, we identified another way N2O use disorder can appear: through exposure for medical purposes.

Scientific evidence validating the beneficial effect of loupes in preventing musculoskeletal disorders is very scarce. The aim of this study was to assess the impact of dental loupes on dental students' posture during a preclinical restorative dentistry course. Using a randomized crossover design, this study was conducted at the School of Dentistry, University of Nantes, France, in 2017. Forty students in their second year of dental study were randomly divided into two groups of 20 each: group A used loupes, whereas group B did not. The week after, students reversed configurations (each subject served as his or her own treatment and control group). Students were video‐recorded during cavity preparation. Trunk, head and neck, and upper arm positions were analyzed using continuous scores based on the modified Posture Assessment Instrument. Additionally, cavities were rated, and students completed a questionnaire on their perceptions of the loupes. On a scale on which lower scores indicated better posture, the results showed significantly higher posture ergonomic scores per minute for students without loupes (146.3±6.64 points/min) than with loupes (123.2±6.77 points/min; p<0.05). The majority of the students (32/39, 82%) showed improvements in ergonomic postures with the use of loupes. Trunk, head, and neck were positively impacted by the use of loupes, but not the upper arms. Cavity preparations were not improved by the use of loupes. The questionnaire revealed negative aspects (pain and difficulty adapting) but underlined the perceived positive impact on posture. This study documented the ergonomic advantages and challenges of introducing magnification near the beginning of the dental training program.

IntroductionThe concept of escape games dedicated to dental students is a new learning experience that has not yet been extensively explored. The aim of this pilot study was to assess the impact and perceived value of an endodontic‐themed escape game as assessed by fourth‐year dental students.MethodsThis study was conducted at the University of Nantes, Faculty of Dental Surgery using a cross‐sectional pre‐ and post‐test research design to assess students' changes in performance. Students in the fourth year of dental surgery study (n = 18) were divided in four groups for this study. The answers to the pre‐test/post‐test were 50 true/false questions. Moreover, a 20‐question perception survey was given to all the participants after completion of the escape game. The study data were collected in May 2019. An unpaired t test analysed the mean differences between the groups.ResultsThe results showed a statistically significant increase in post‐test results (75.33% ± 10.17% of correct answers) compared to the pre‐test results (67.33% ± 5.94% of correct answers) P < .05. Analysis of variance revealed that this change in score was not significantly different between the four groups. The students perceived the endodontic‐themed escape game to be relevant. A one‐sample t test indicated that students' mean (SD) perception 4.4 (0.7) was statistically significantly higher than the mean value of the evaluation scale P < .001. The students found this educational game to be a useful experience that helped them recall/apply knowledge whilst promoting teamwork.ConclusionTherefore, this type of game can enhance students' learning and motivation.