A comparative histologic study of rapid three-dimensional zygomatic suture expansion osteogenesis

To explore the histologic changes in zygomatic suture with 3-dimensional (3D) zygomatic suture expansion osteogenesis (SEO).

The zygomatic bones were drawn by 3D external expansion appliance, and sutures of the zygomatic were extended. Biopsy specimens of the zygomatic bone were collected after 1, 3, 5, and 8 weeks. Each specimen was stained with Triplex staining as well as hematoxylin and eosin (HE), and the histologic changes were evaluated compared with the control section.

With the 1-week study group, there were visible fibroblasts, osteoblasts, and capillary vessels in the expanded suture tissues. The fibers were connected to the sides of suture in an orderly way. In the 3-week group, active bone formation can be seen in expanded sides. The bone trabeculae were matured and oriented in the direction of distraction in the expanded sides of suture and most of them were collagen fibers; but the tissues of both sides of expanded suture were not in order. New woven bones were found in the histologic sections of the 5-week group. In the 8-week group, reticular and elastic fibers could not be observed, and bones were formed completely. Compared with the histologic examination of the same tissue section and its change in different periods of the biopsy specimen with Triplex staining and HE staining, the method of Triplex staining showed more clearly in collagen, reticular, and elastic fiber examination. The superiority of HE staining was in showing fibrous tissue, shape of cells, and bone formation in various degrees of maturation in rapid SEO. It is suggested that the 2 staining methods might be combined in distinguishing the collagen as well as reticular fibers from fibrin in the same section simultaneously.

Collagen fibers and new bones were observed to form rapidly in expanded sides with direct SEO. Continual affluent blood supply, integral structure of periosteum and synostoses in the suture, and rapid uniform calcification of the whole new tissues are the histologic characteristics of SEO.