The interplay between sagittal and vertical growth factors. An implant study of activator treatment

Changes in sagittal jaw relationship are dependent on an interplay between a series of basal and dentoalveolar changes in both sagittal and vertical planes. The present article uses the implant method to examine and discuss this interrelationship as well as condylar growth and, in addition, comments on the relative value of accepted methods of expressing sagittal jaw relationship. The interplay between vertical and horizontal dentoalveolar, sutural, and condylar changes occurring relative to the occlusal plane in nineteen patients treated by means of activator was studied quantitatively by means of the implant method. Changes in the sagittal jaw relationship were evaluated by means of the change in ANB angle and utilizing the "Witts appraisal" with a modified occlusal plane construction. Change in sagittal jaw relationship was studied by means of a correlation analysis and shown to be largely dependent on the spatial development of the mandible; the latter was positively correlated to vertical condylar development and maxillary horizontal development but negatively correlated to increase in vertical sutural and dentoalveolar parameters. Vertical condylar development was also demonstrated to influence the rotational pattern of mandibular development. The clinical importance of controlling vertical development, sutural as well as dentoalveolar, in the treatment of sagittal discrepancies was stressed through the findings of the present study.