RADIOGRAPHIC OBSERVATION OF RAPID EXPANSION OF HUMAN MAXILLA

Abstract

An attempt was made to study the process of the separation of the human mid palatal suture by rapid expansion and the subsequent restorative changes. Fixed type orthodontic plates with expansion screws were inserted into eight orthodontic cases with the lateral compression of the maxilla. The amount of the expansion was measured on the occlusal x-ray pictures and the restorative process was observed. The conclusions are summarized as follows: 1. The mid-palatal suture could be separated to some extent in the palatal bone area. 2. The restorative process started by the spicule formation and the ossification were completed two months later. 3. The intra-alveolar changes of the anchor teeth did not exceed the amount of the separation a t the mid-palatal suture. 4. The increase of SNA and the decrease of SNB were dominantly observed, resulting in the significant increase of ANB. 5. No distinct information on the effective age for the application of the rapid expansion could be obtained. 6. The rapid expansion should be an effective method of practical orthodontics to reduce the skeletal deficiency such as the lateral compression of the maxilla as well as the functional interference resulting from the skeletal deficiency.