Abstract:

Objective:The aim of this experimentwas to study the characterof degradation of super-highmolecularweight poly-DL-lactic acid (PDLLA) internal fracture-fixing system.Methods:The fracture mandible of dogswas fixed with super-high molecularweight PDLLA internal fracture-fixing system. In 1, 3, 6, 12 months afterthe operation, the materialswere taken outfrom dogs, and the palateswere observed using the scanning electron microscopy.Results:The surface of super-high molecular weight PDLLA was coarse. In 1 month after the operation, there were much chaps and grains on the surface of PDLLA. In 3 months after the opera- tion, there were much deeper grooves. In 6 months after the operation, only some scraggly accumulation was seen.Conclusion: Super-high molecularweightPDLLA can degrade on the surface in the beginning, and then the material begins to degrade deeply. The speed of degradation matches with the speed of fracture healing. Itwill help to avoid stress-protecting effect.

Key words: poly_DL_lacticacid degradation, ultrastructure