Interceptive and preventive orthodontics are the earliest forms of orthodontic therapy to be performed already in the primary or early mixed dentition. Preventive orthodontics deals with educating parents and children about harmful oral habits and preventing them from occurring, while preventive orthodontics eliminates oral habits and stops further progression of orthodontic anomalies and their complete development. Oral habits are thumb-sucking, bottle-feeding, use of pacifiers, infantile swallowing type and mouth breathing. Breastfeeding is an oral habit that is desirable to last as long as possible. Thumb sucking is a very well developed mechanism that can occur even intrauterine, and is also transmitted to the period of deciduous and permanent dentition. Sucking the thumb for more than four years and more than six hours a day causes protrusion of the upper incisors, retrusion of the lower incisors, anterior open bite, enlarged overbite, overgrowth of the posterior teeth, prevention of eruption of the anterior teeth, cross bite, and V-shaped upper arch. Similar clinical findings have been reported in some children who have been fed to a bottle for a long time or who have used pacifiers. Pacifiers are divided into physiological and non-physiological. Non-physiological pacifiers in most cases cause protrusion of the upper incisors and protrusion or retrusion of the lower incisors, anterior open bite and posterior cross bite. Anatomical pacifiers stimulate breathing on the nose. Breathing through the mouth or oral respiration can be anatomical, obstructive, and acquired in nature. Open mouth, tongue position, jaw and head cause changes in tooth and jaw position. Breastfeeding is a habit that is desirable to last longer than the first six months of life. Breastfeeding consists of a static and dynamic phase. Static breastfeeding phase enables transverse jaw growth while dynamic phase sagittal jaw growth. Infantile type of swallowing is present during breastfeeding and in most cases at the age of 6 it switches to mature or somatic type of swallowing.