It is considered that orthodontic treatment is difficult for open bite which is associated with habits such as finger sucking and tongue thrusting. If these habits are not broken, the orthodontic treatment will not be successful. Furthermore, if these habits are not broken and the open bite is not treated, the open bite will shift skeletal one. For three cases with open bite in the growth period, we tried to treat open bite by means of habit breakers.We used three types of habit breakers; atongue crib, a lingual arch with spur, and a plate with spur. In these cases, it was shown that these three habit breakers have similar effectiveness in treatment of open bite. The improvement of open bite is caused by extrusion of the anterior teeth and is seen on analysis in the superimposition of cephalometric radiogram of the view at pre-treatment used of habit breaker and post-treatment. After active treatment by multi-bracket appliance, relapse of anterior overlap was not seen, and occlusion was stable.After active treatment, whether the tongue thrusting habit and abnormal anterior position of tongue was improved or not dominates the prognosis. In order to stabilize occlusion, it is necessary, in a patient with a serious tongue thrusting habit, to acquire a normal tongue function and to harmonize tongue function and muscle circumference of the oral cavity by means of a retainer with spur, and also by myofunctional therapy.
