Abstract:

Objective　To observe mandibular fracture healing after synthesized bioabsorable poly-para-dioxanone (PDS) ligature fixiation.Methods　Para-dioxanone monomer was prepared by chemical reactions of metallic sodium, ethylene glycol and other rawmaterials. PDS was synthesized by polymerizing the purified para-dioxanone in the presence of catlyst under the condi- tions of negative pressure and certain temperature. PDS ligaturewas obtained by processingthe polymer into small granules, drying and melt-extruding through a spinnerette. Eighteen adult male NewZealand rabbitswere assigned randomly into two groups. After mandibular fracture modelswere created, reductions of the artificial fractureswere accomplished bymeans of transosseous PDS lig- atures on each of 12 rabbits in experimental group. While the other six rabbits without any internal fixation were set as control. Schedules for killingwere arranged to give postoperative samples at two-week interval till 12thweek.Results　Radiographical and histological examinations demonstrated that all fractures fixed with PDS ligatures healed without any complication. Periosteal and cartilaginous osteogenesis was observed in newly formed external callus. In contrast, bone fragment migration and the consequent nonunion occurred in the control group. PDS ligature degraded and absorbed without interference with osseous union and healing. The tensile strength reduction of PDS ligature was prior to its absorptionin vivo.Conclusion　The synthesized PDS is a colorless, flexible, themoplastic and monofilament fiber, which can be sterilized by ethylene oxide embalmmentwithout serious loss of tensile strength. It seems that the application of this macromolecular material in internal fixation is of great worth for further study.

Key words: biodegradable, poly-para-dioxanone, mandible, fracture, internal fixation