Response to nitrous-oxide and oxygen among dental phobic patients

The present study evaluated the records of 27 patients (20 men, 7 women) who were treated under nitrous-oxide (N2O) and oxygen sedation due to extremely high dental anxiety. Corah's DAS and Kleinknecht's dental fear survey were completed by the patients. Patients who responded positively to the gas were categorised as N2O+ patients, whereas those who responded negatively were categorised as N2O- patients. A mean DAS score of 19.3 +/- 1.6 was observed for the entire population. No significant difference was found between N2O+ patients and N2O- patients in any DAS item, nor in the total scores (19.4 +/- 1.35 and 18.67 +/- 2.24 respectively). Only in answer to the question, 'Has fear of dental work ever caused you to cancel or not appear for an appointment?' were the scores of N2O- patients significantly higher than of N2O+ patients. No differences were found between patients who reported pain as the source for their dental anxiety and those who did not; between patients with gag reflex and those without, between patients who had never had any dental treatment and those who had, and between patients who required two or three appointments before administration of the gas with respect to successful treatment under N2O and oxygen sedation. Among the N2O- group, significantly more patients did not attend for two appointments or more. The results suggest that lack of keeping previous dental appointments may indicate patients' possible negative response to nitrous-oxide and oxygen sedation.