Over the past few years role of virus in causing oral diseases has come into picture. All oral diseases are thought to be of bacterial origin but modern techniques in microbiology have singled out many viruses causing diseases. Early detection of etiology causing diseases leads to proper treatment. Viral etiology has led to a different therapeutic approach consisting of anti-viral agents. This book will be helpful for graduates and post graduates in the field of microbiology for looking beyond the conventional etiology for oral diseases.