This is the first-ever study which compares the efficacy of PROBIOTICS and FLUORIDES in reducing S.mutans levels in orthodontic patients. It is an in- vivo study. It comprises of inter and intragroup comparisons of different delivery systems of probiotics and fluorides. A dedicated effort has been made by the author to incorporate all the tiniest details and pictures to make it easily understandable. This book is for all the Orthodontists and would help them to prevent white spot lesions.