Aside from restoring biting and chewing capability to the mouth, dental implants also serve a cosmetic function.  The most obvious benefit to an implant patient's appearance is that the replacement tooth fills in the gap left by the lost tooth with a natural-looking substitute.  On a deeper level, dental implants help patients avert bone loss.  Without implants, missing teeth and associated bone loss cause the lower third of the face to collapse and shrink inward.  As the anchoring portion of a dental implant forms a strong bond with the jaw, it stimulates the surrounding bone and preserves it.  As a result, the bone loss that would otherwise be inevitable with missing teeth is avoided.

P.S. One of the factors that is used to assess a patient's suitability for a dental implant is the amount and density of underlying bone in jaw.