RESTORATION OF MANDIBULAR NONUNION BONE DEFECTS - AN EXPERIMENTAL-STUDY IN RATS USING AN OSTEOPROMOTIVE MEMBRANE METHOD

Standardized through-and-through critical size defects were created in rat mandibles. After 12 weeks, the sites revealed a massive ingrowth of soft connective tissue, forming a transosseous core filling the def ects. Upon reentry, the soft tissue inside the remaining bone defects was removed. On one side of the jaw, the defect was covered both bucca lly and lingually with an expanded polytetrafluoroethylene (e-PTFE) me mbrane, but on the other side no membrane was placed. Histologic analy sis after 6 weeks revealed an essentially complete healing with bone o f the membrane-covered defects. No cartilage was present in any of the specimens. At the control sites (no membrane), the amount of newly pr oduced bone showed variations, most through defects revealing the pres ence of a remaining central portion of connective tissue. This investi gation thus showed that predictable and successful bone regeneration c an be achieved by the osteopromotive membrane method in treatment of n onunion defects filled with mature connective tissue.