I finally made it to a dentist. I went to Dental Arts. Their FB page has the correct location:
https://www.facebook.com/thedentalartsThey answer very quickly on both FB Messenger and SMS.
This is in the Seub Siri area in the townhouse complex (Pandin Tong City) across from Talat Lotus and near the Kasikorn Bank on the highway.
I saw Dr Suwat. He's great. Speaks excellent English and explains everything as he goes along. His equipment and techniques seem very up-to-date.
The price was fine: 2K baht for cleaning and plaque removal, three x-rays and fluoride treatment.
I didn't need any fillings or other work.
I definitely will return. I very much liked his English ability and his concise explanations of everything he was doing or was about to do.