The influence of genetic variability on treatment outcomes has its effect both in medicine as well as in field of periodontics.While there have been dramatic successes in identification of mutations responsible for rare syndromic forms of periodontitis, few genetic polymorphisms reported for more complex genetic forms of periodontitis have been demonstrated to be clinically valid or to have clinical utility.This book reviews the fundamentals necessary to enhance functional polymorphisms for new therapeutic approaches to treat diseases and will allow the targeting of new and existing therapies to those patients who will derive the most benefit without the risk of serious side effects.The text has been taken from various standard books, e-books, journals and websites etc.