Dentures are removable appliances that replace missing teeth. Depending on your needs, you can get either complete dentures or partial dentures. Complete dentures are used when all the bottom or top teeth need to be replaced. Dentures that replace just some of the teeth are called partial dentures. Both options allow you to eat food easier, speak clearly if you had problems speaking well because of missing teeth and help support cheeks and lips to prevent sagging in the face.