1)apparently, the Amalgam is not the cause of inflammated gum and toothache. What the dentist said about the cause? May be you have infection and your root canal has to be redone (and get the mercury out). The Amalgam filling would not cause AF by itself.
2) You have AF so that enema, liver flush, etc. are extra stressors for the body. It would not be a good idea. You may also check one of my post with Dr Wilson's cleansing recipe. He mentions that Colloidal Silver more effective than Coffee-Enema and less invasive.