I asked around online and found a dentist in Daejeon who spoke English and wouldn't try to rip me off and push me into doing work I didn't want or need done. Turns out there is a highly recommended dentist only 30mins walk from my place, Berkeley Dental Clinic. I definitely recommend Berkeley Dental. The dentist spoke good English and took the time to explain everything to me. She told me about the different filling choices (they don't use silver due to the mercury), was up front about the price differences and didn't apply any pressure to me either way.
To get there take exit 4 a Tanbang station and walk straight (50m) until you hit the main road. Turn right and walk about another 60m.
On the 5th floor, you will find Berkeley Dental Clinic.
It is nice and quiet. I went in what I thought would have been the busy time (late in the afternoon after work), but I arrived to find no one else in the waiting room. The friendly staff handed me a form (in English) to fill out about my health and dental history before we got started.
The dentistry is modern and clean. They even have this cool tool which my dentist in Australia doesn't have. They take a photo of any teeth they suspect as being problematic so both you (the patient) and the dentist can get a good look at them on the computer screen.
I actually went to this dentist twice. First time was for a checkup, cleaning and fluoride treatment. That came to 30,000 won (about $30). The second time I went back (a couple of days later) to get 6 small fillings. That came to 37,000 won (about $37). I was rather shocked to hear that I had 6 cavities. My dentist in Australia always told me I had excellent teeth and never hinted at any cavities, but I could see from the photos she took of my teeth that there were small cavities. She told me that some dentists don't worry about small cavities which may be why my Australian dentist didn't say anything. Cheese.