As far as the dentists go I know the Dental College of Philadelphia has an AirGas truck come in and drops off a ton of bottles every so often. We were working there and man was I drooling when he showed up. I think AirGas owns the rights to Nitrous Plus but I might be wrong. They were raping me for around $200+ for a mother bottle including rent and hazmat fees a couple of years ago. The price went up $30 in the off season so I ditched them and went with the medical grade stuff. It is still $160 for a mother bottle but no rent and no other fees to give you an idea on pricing. I am sure others can get it cheaper.