Having mercury filings replaced will release some mercury that is absorbed. While having teeth pulled will not release that mercury, the problem is that people need their teeth. If you have them pulled, will you get implants or bridges to replace the pulled teeth? Implants and bridges are expensive and might cause many problems. So while having mercury fillings drilled out does not seem ideal, the other options usually seem much worse. I guess many people could probably live without wisdom teeth(the rearmost molar), although they do help quite a bit in having food ground into smaller bits, which helps with digestion. If someone has a tooth pulled that is in the middle of other teeth, if the space is not filled, then the adjacent teeth will shift, which can cause many problems.