When you say filling a tooth, it's actually called restoration. If the defect is half, it may leak slurry. Before post crown restoration, root canal therapy is needed to remove necrotic pulp. As for the cost, it depends on what materials you choose. General materials, such as cobalt-chromium post and cobalt-chromium crown, cost about 2000 yuan. As for life span, it needs to be emphasized that it is close. As long as it is close to accuracy, it is generally about 20 years.