학위논문 (석사)-- 서울대학교 대학원 : 의학과 의공학 전공, 2013. 2. 최영빈.ABSTRACT
Introduction: Currently, titanium alloy systems have been
used for the treatment of bone fracture. This device has
many advantages such as the reduction of healing time
and the convenience in operation process. However,
concerns about infection, exposure, transcranial migration,
and growth restriction when using metal devices were
reported in studies. To overcome these problems with the
conventional metallic system, a variety of bioabsorbable
materials have been developed for the treatment of bone
fracture. Plate and screw fixation techniques for fracture
healing had been boosted with the development of new
biocompatible materials. The aim of this study is to
evaluate the effects and safety of recently developed
bendable bioabsorbable plate and screw device system in
mandibular fracture in a rabbit model. The success of this
system in mandibular ramus, which is known for highload-
bearing site, might suggest the usefulness of given
bioabsorbable plates and screws.
Methods: We investigated the efficacy and safety of
recently developed bendible bioabsorbable plates and
screwwhich are made of PLGA (polylactic-co- glycolic
acids) and 100% poly (L-lactic acid) only in a rabbit model.
In vivo mandibular fracture model in rabbit was introduced
to evaluate the efficacy and biocompatibility of the each
fixation system. Twenty-five New Zealand white rabbits
for each system were randomly assigned for each system.
At 4, 6, 8 and 10 weeks after implantation, tissue
specimens were taken from the implanted sites of the
rabbits and histological analysis was performed for the
each of the specimen.
Results: Until 6 weeks, both devices of fixation system
showed similar result. After 4 weeks, plates and screws
were covered by amorphous connective tissues and
overwhelming severe active chronic inflammation in soft
tissue has observed. After 6 weeks, the inflammation
decreased and some of the specimens exhibited new
bone formation around the end of a fracture line. After 8
and 10 weeks, in the case of PLGA made plates and
screws, new bone formation was observed with all
samples without severe inflammation, implying the
healing statue of the bony fracture. Meanwhile, rabbits
with PLA plates and screws showed incomplete bone
remodeling although new bone formation and increase of
bone thickness were observed.
Conclusion: Given by these, it could be suggested that
biodegradable plate and screw systems that we evaluated
in this work be effective for treatment of mandibular
fracture, one of the sites under a high load-bearing
condition. The adjustment process and long-term followup
study is in progress for clinical application of this plate
and screw system.
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Keywords: bioabsorbable plate and screw, bone fixation,
PLGA (polylactic-co- glycolic acids), PLA(polylactic acid),
biocompatibility
Student number: 2011-21883CONTENTS
Contents
Abstract .................................................................. i
Contents ............................................................... iii
List of Tables and Figures ....................................... iv
Introduction ........................................................... 1
Material and Methods ............................................. 3
Results .................................................................. 9
Discussion ........................................................... 18Maste
