Growth in width of the maxilla studied by the implant method.

Abstract

The transverse growth of the maxilla was studied radiographically by means of the metallic implant method. The sample consisted of 9 boys without malocclusion of the teeth. They had never received orthodontic treatment and were followed longitudinally by annual registrations from 4 years of age. Sutural growth in width of the maxilla was determined from frontal radiographs as the increase in the distance between metallic implants inserted at the lower aspect of the maxillary zygomatic process on each side. The shape of distance and velocity curves representing transverse growth in the median suture was similar to the shape of the curve representing the growth in body height, both showing a distinct puberal growth maximum. The individual time of puberal maximum for the transverse sutural growth coincides with the time of puberal maximum of facial growth, measured from implants on profile radiographs. The individual time of growth completion in these sutures also coincided, occurring on an average of 17 years of age. The development in width of the maxillary dental arch, measured between the first molars, showed a small puberal growth spurt, but the total increase in width was only about one fourth of the sutural growth in width of the maxilla in this area. To assess whether growth in the median suture was of the same amount throughout its length, metallic implants were also inserted anteriorly into the maxilla on each side of the median suture, on a level with the apices of the central incisors. With correction for differences in magnification on the frontal radiographs, the increase in distance between the laterally placed implants was three times greater than between the anterior implants for a corresponding period of time. This demonstrates that the sutural separation of the two maxillae was greater posteriorly than anteriorly, and consequently they rotate in the transverse plan in relation to each other. The influence of the transverse rotation of the two maxillae on the development of the maxillary dental arch is discussed.