A tooth has two parts: the crown and the root. When a tooth falls out, the section of the jaw that supported the tooth has no purpose, so it withers and atrophies. Your remaining teeth are then supported by a weakened jaw. A missing tooth also increases the workload of remaining teeth, and to balance the load, teeth shift, which can cause spaces between teeth, food impaction, and tooth decay. After about four to eight years, remaining teeth will begin to fall out as well. Up to 19% of adjacent teeth are lost as the result of a missing tooth. That's five more lost teeth if you started with a full set!