In medicine, prevention is better than cure. A check-up allows your dentist to see if you have any dental problems and helps you keep your mouth healthy. Leaving problems untreated could make them more difficult to treat in the future, so it’s best to deal with problems early, or, if possible, prevent them altogether.
The tooth in the photo was removed due to gum disease caused by the build up of tartar which is the darker material around the roots in the photo. Good daily brushing and flossing along with regular professional cleaning can help avoid this. Tartar starts out as plaque – if not removed it can cause the gum and bone to recede, which will loosen the tooth. The loosened tooth, even if intact like this one, may then need to be removed.