Mentoplasty is a term that refers to plastic surgery procedures for the chin. It comes from the Latin word mentum, which means chin, and the Greek verb plassein, which means "to form" or "to shape." Mentoplasty is also known as genioplasty or chinplasty.

Mentoplasties fall into two large categories: procedures that augment (increase) small or receding chins; and those that reduce large or protruding chins. Chin augmentation is done more frequently than chin reduction, reflecting the fact that microgenia (small chin) is the most common abnormality of the chin.

From http://www.answers.com/topic/mentoplasty