Good question. Also, what's the best place to get hernia surgery? I'm serious.

The Franco-Vietnamese Hospital has very good, English speaking dentists.
Just call in advance and make an appointment.

There's a good dentist on Nguyen Du a couple of shops before Pho Hue. I get my teeth cleaned there all the time - they do it with a water pic - no scraping. Last time I was there it was 150,000 for a cleaning, and about the same for a filling.

They do have some English, but how useful that is when your mouth is full of implements I don't know.

There is one very good dentist working in the Army hospital 108 (in Tran Hung Dao St) His name is Anh Tuan, about over 40, he can speak English (I think) cause he graduated in Hongkong.
Here's his number: 0903 235523