The Changes by the Distal Movement of Maxillary First Molars in the Gnathofacial Region

Abstract

For the purpose of determining an influence in the gnathofacial region by a distal movement of the maxillary second molars, the author compared 19 cases of the maxillary protrusion who had worn the Kloehn type cervical pullgear longer than 1 year and 3 months with 19 controls who were diagnosed as the maxillary protursion cases but did not receive an orthodontic treatment.As a result of analyses of the serial cephalograms taken of these two groups, the author arrived at the following conclusions : 1. Movement of the maxillary second molars by use of a maxillary headgear influences the overall maxillary region of human face.2. With the experimental or treated cases, both the palatal and occlusal planes were observed to perform a clockwise rotation.On the other hand, SNA and point A became deviated downward.3. In the upper portion of face, the growths of individuals were found to play a stronger part than an orthodontic force and, for this reason, a degree of change owing to an orthodontic force was less than in other facial portions.4. Changes in the gnathofacial region were diverse in individual cases. However, within the scope of the present study in which the school-age subjects (111A and 111B) were selectively used, it was confirmed that as the general tendency an application of a maxillary headgear tended to inhibit the foreward growth of gnathofacial region with an attendant increased growth in the downward direction.Moreover, its effect extended to the sphenoid bone and its neighborhood. From this fact, its possible influence on the base of skull may be reasonally inferred.