This document provides an overview of oral habits, focusing on thumb sucking. It begins with definitions of oral habits and classifications of useful versus harmful habits. It then discusses the etiology, prevalence, and development of habits. Specific sections cover thumb sucking phases, effects on dentofacial structures, diagnosis, and treatment approaches. Treatment may involve psychological therapy using techniques like habit awareness and reward systems, or devices like thumb guards to discourage the habit. The goal is to help children overcome thumb sucking and support healthy oral development.