The roots of the teeth green may be caused by dental calculus or bacterial erosion of the pulp. 1. Long-term inattention to oral hygiene: inattention to hygiene leads to bacterial deposits on the teeth, the formation of calculus in the roots, long-term stimulation of the teeth, will make the gums shrink, food coloring in the calculus, so that the roots of the teeth become green. 2. Teeth corrode the pulp: after the tooth is missing, bacteria corrode the pulp, making the pulp cavity green. The pulp cavity is getting thinner and thinner, exposing the nerve to cold and heat will be sore. The first situation caused by the green, you can use ultrasound, medicine, rinse. The second caused by the green, you should go to the regular dental hospital, resin filling repair, repair as soon as possible to avoid damage to the nerve.