X-ray does'nt always reveal decay within a crowned tooth.However, careful clinical probing with explorer can detect marginal decay and penetrating through the surface if there is presence of deacy.
i would go to the ear nose and throat doctor. throat problems can cause mouth odors too. if its a tooth and it was so badly infected there would probably be pain, swelling, discomfort. antibiotics are not made for long term use. the more you take them the less effective they become so its more difficult (and sometimes impossible) to treat future infections.
I wrote this many years ago, and my husband problem was throat cancer. He had it treated and now is cancer free. Just wanted to update this. God Bless. In Christ Pam Holloway
We prayed and believe we got a miracle and went for cancer treatment, he was cancer free by Dec. 2008