I didn't go to the dentists for ten years. I don't have a real phobia, just a little one. My friend suggested I go in and ask for Nitrous (we shared a dentist back from the days I went to a dentist, so I know he did the gas.) So, I had that. It certainly took the edge off the first few couple of cleanings. I asked them to turn down the gas, it was too much. I have since then once had a cleaning without the gas, but usually I ask for it, but it barely makes a difference.
lhamo, you should find a dentist that gives the gas. I have somewhat sensitive gums, but I don't think they are extremely sensitive.
And my teeth didn't suffer from no dental care for ten years, just to report. I've got really great teeth, less so the gums.