الفهرس 
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Abstract
Summary The present study was conducted to evaluate the effect of rapid distraction
rate on the quality and quantity of mandibular new bone regenerate following
DO in goats. The rapid distraction rate was 2 mm/day.
The study was conducted on 14 goat. The animals were divided to two equal
groups. Group I (Study group), the distraction rate was 2 mm/day for five
days. Group II (Control group), the distraction rate was 1mm/day for 10 days.
The regenerated bone in this study was evaluated by clinical examination,
macroscopic examination, radiographic assessment and histological
evaluation.
Clinical examination of the animals was used to assess mandibular
deviation after the distraction period. Macroscopic examination was
performed by 3D measurements of the sample. These measurements may
assist to compare the total bone thickness among the two groups.
Radiographic evaluation of the samples was done through scanning by
CBCT. CBCT was suggested as reliable volumetric quantitative parameter to
evaluate bone density by using Hounsfield unit during bone healing and
correlates significantly with histological findings. Histological examination
of the newly regenerate bone was the comprehensive evaluation.
Haematoxylin and Eosin slides, Masson Trichrome slides and morphometric
evaluations were used to allow the assessment of many parameters related to
numerical, dimensional and geometrical object features. The bone quality was
evaluated by histological assessment of the distracted gap, while the bone
quantity was evaluated through computerized histomorphometry. Image
analyzing system was used to calculate area of osteoid percentage, cortical
and trabecular bone thickness
The mandibular deviation was a dominant feature in both groups as well as
the complications, which were observed equally. 3D measurements were
comparable between both groups with no statically significant. Bone density
of the study group was lower than the control group, but it was not statically
significant. The histological study of the slides showed comparable quality of
the tissues between the two groups. The histomorphometric study showed
comparable results as regards area percentage of osteoid tissue with no
statically significant, but there were a statically significant in cortical and
trabecular bone thickness.
Conclusions:
Based on the results of the current study, it could be concluded that:
1. Rapid distraction rate affects the microscopic bone structure at the
level of the cortical and trabecular bone thickness.
2. Rapid distraction rate do not affects the macroscopic bone structure.
3. The major difference between the rapid and standard distraction rate is
in the degree of bone maturation.
Recommendations:
1) The time difference between rapid and standard activation periods, if it
added to consolidation period of rapid distraction it may achieve a
comparable bone maturation to that achieved by standard distraction rate.
2) To decrease dehiscence observed around the sub-cutaneous distractor, it
is recommended to use alternative distractor devices.
3) Utilizing other radiographic methods (CT, DEXA and Ultrasound) and/or
softwares to evaluate the bone density are recommended.
4) It is recommended to study the effect of continuous rapid rate compared
with the intermittent standard rate.
5) Rapid distraction rate could be used in pediatric patients with craniomaxillofacial
malformations due to abundance in blood supply.
6) To improve maturation of bone with rapid distraction rate, further studies
are recommended by using adjunctive modalities as Mesenchymal Stem
Cells.