I'm not sure if this is the correct forum to ask but I'm a patient looking for some answers about anaesthesia done during dental work.

I have an extremely sensitive gag reflex so in order to get fillings completed, my dentist enlisted the services of an anaesthesiologist who was going to administer deep sedation through an IV.

Apparently, once I was under sedation and asleep, they were able to complete about 4 xrays but they said I started gagging up bile, so they stopped work. They suctioned me to prevent fluid being aspirated into my lungs and as a safety precaution, called an ambulance to take me to an ER.  I was completely unaware of anything that was happening until I woke up on a stretcher.

The anaesthesiologist says that I have the strongest gag reflex he's ever seen and his suggestion is that for dental work, I should probably have it done in hospital under general anaesthesia with a breathing tube inserted.

My question is, I don't quite understand how I can be basically asleep and still have a gag reflex that strong.   Is this something to do with the type of anaesthesia used?  And has anyone experienced this kind of situation with a patient?

Thanks in advance.