Oral scleral heterografts. A pilot study.

This study showed that scleral heterografts in the oral cavity work. Such grafts demonstrate the following characteristics: (1) attach firmly to submucosal, periosteal, and bony tissues; (2) remain firm and fibrotic in nature, indicating the possibility of a stressbearing tissue; (3) show little or no scarring or contracture; (4) show minimal, or no- host antigenic response based on clinical acceptance; (5) appear to become vascularized and cellular, blending with adjacent collagen. As projected by this study, scleral heterografts might well be used to obliterate bony undercuts and perhaps to obtund cystic cavities and other major bony defects. Further studies of layering of the sclera are essential before any definitive result can be determined in large bony defects. In those areas in which no bone regeneration would be feasible, such as in the mylohyoid region of the mandible, this application does present a possibility for removing undercuts as opposed to removing overlying bone. The tenacity of adherence to submucosal tissues, periosteum, and bone makes scleral heterografting even more intriguing in the possible obliteration of oroantral fistulas. We might theorize that the sclera would not only attach to the buccal and palatal flaps but also show a rather firm and tenacious adherence to the bony walls of the antral defect. The availability of human bank sclera for use as presently made by periodontists and as pioneered by Klingsberg is somewhat limited. From our study, an extrapolation would indicate that, because of the comparably low and antigenicity of bovine sclera and human sclera, an investigation in this area should be completed in order to determine whether scleral heterografts can replace scleral homografts in human periodontal surgery. Sclera is easily preserved in anhydrous glycerine (as preserved by King and associates19) and can certainly be stored in banks. In our opinion, the final application of scleral heterografts, human or bovine, the role of antigenicity, and the ability of osteoblasts to invade either a single piece or layers of sclera warrant further study.