Bad Bacteria attacks your gums causing loss of teeth, a bad odor or gum recession. When calcium building up because of Bad Bacteria, plaque forms on the teeth. This is easy to get rid of and prevent deposits when brushing. There are infectious (Bad) Anaerobic bacteria that are building up to leave calcium deposits on your teeth, known as tartar or calcium plaque, which has a yellow or brown color. These deposits cause an awful odor, red bleeding gum infection, i.e. gingivitis.