My biological dentist also replaced my mercury fillings with long-term temporary fillings, which need to be replaced after about a year. The idea behind it is that the body is highly reactive to all substances because of the mercury - you may have more allergies or food intolerances, for example. There is also a danger that you will react more to dental materials, and actually become more ill. There are several cases of this on this forum.

So my dentist has used the most neutral dental material for the temporaries, while the body cleans itself for a year to 18 months after amalgam removal. I have already been tested for bio-compatible materials, and will have the temporaries removed soon.

I think this is one of the safest ways of replacing fillings, but yes, you are right, it is more expensive and probably harder on the teeth. But if you have the permanent fillings placed straight away, you may react to them, or become reactive to them as your body changes.

Hope this helps
Nicola