| Summary: | 碩士 === 國立臺灣大學 === 牙醫學研究所 === 81 === The mandibular osteoradionecrosis(ORN) is one of the most ser-
ious complications of the head and neck cancer patients who
rec- eive R/T. The purposes of this experiment are to build up
an an- imal model of ORN and to use this model to find-out a
simple and effective method for preventing and treating ORN.
Forty-six 12-week-old male guinea pigs were included in this
study. The experimental group consisted of 40 animals which
were equally divided into 4 subgroups: A1,A2,B1 and B2. All the
ani- mals in the experimental group received Co-60 radiation
with a dosage of 500 cGy twice a week for 3 weeks. The total
accumulat- ive dose was 3000 cGy. One week after irradiation,
all animals were drilled a hole over the left alveolar ridge.
Group A1 and A2 received intraperitoneal injection of
pentoxifylline 10 mg/kg every day for 90 and 45 days,
respectively. Groups B1 and B2 re- ceived normal saline for
instead. The remaining 6 animals were as control group. At the
end of the experiment, all animals were were sacrificed and the
mandibules were removed for histological examination and
microradiographic study. Histological examinati- on revealed
complete healing of the bone wound after 45 days in the control
group and 90 days in the experimental group. The co- mmon
histological findings were dilatation of bone marrow cavi-
ties, fibrosis and fatty degeneration of the marrow, as well as
increased and prominent reversal lines. Severe inflammation and
sequestrum formation were found in one animal (10%) of B1,B2,
but not found in A1,A2. The microradiography combined with bone
density measurement revealed that the irradiation could retard
bone healing process and interfere with the bone deposition.
Al- though pentoxifylline injection could promote bone healing,
it need 90 days to achive its efficacy.
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