الفهرس 
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Abstract
Our study was conducted to evaluate osteogenic potential of GMSC on chitosan scaffold in treatment of peri-implant defects. It was conducted on a total of ten mongral dogs with age average of 1.5 years old weight average of 22.5kg. They were divided into two groups each containing 5 dogs. group 1: include 5 dogs were sacrificed at 1 month interval Each dog was divided in a split mouth design into right side (intervention group) where peri implant defect was treated by GMSC on chitosan scaffold and left side (control group) which was treated by chitosan scaffold only.
group 2: include 5 dogs were sacrificed at 3-month interval. As in
group 1 each dog was divided in a split mouth design into right side (intervention group) where peri -implant defect was treated by GMSC on chitosan scaffold and left side (control group) which was treated by chitosan scaffold only.
Under sterile conditions, the third right and left mandibular premolar teeth were extracted by making vertical interradicular section, each root was carefully elevated and then gently extracted. Mesial sockets were then drilled following the basic surgical principles governing the placement of dental implants.
Thereafter, the interradicular septa were resected with a manual rongeur Friedman to create bony defect adjacent to the distal socket measured 6 mm height, 4 mm in the bucco-lingual direction, and 5 mm in the mesiodistal direction in the mandibular bone.
After a complete alveolar cleaning, solid cylindrical titanium plasma sprayed (TPS) screw implants (3.1 mm diameter;9 mm long Dentium implant, Korea) were manually inserted in the implant beds implants were covered with 1.5 mm closure screws. Then peri-implant defects were treated as previously discussed by GMSC on chitosan scaffold or by chitosan scaffold only according to the side.
The results were evaluated radiologically and histologically.
Radiographs were taken before, immediately after surgery then at 1 month for group 1 and 3 months for group.2. Radio-densitometric evaluations were done using the Digora software system, around the distal surface of the implant in both groups. The bone density was measured using grayscale value.
Histological evaluation was done qualitatively with light
microscopy for slides stained by H&E and Masson stains. While
quantitative evaluation was done using Digital Image J software which measure area fraction of Masson-stained slides giving amount of newly formed collagen type I.
The results of group 1 were statistically significant between the
GMSC side and unloaded chitosan side regarding bone density at followup and the change in bone density. Also, there was a significant difference in histological readings by image J analysis software, as collagen formation was higher in GMSC sides. At group 2 there wasn’t any significance in results radiologically or histologically although GMSC gave higher results.
Qualitative histological evaluation at group 1 H&E sections of
mandibular bony peri-implant defects in dog of chitosan showing darkly stained newly formed woven bone rich osteocyte content with bone marrow cavities but a photomicrograph of a paraffin section of mandibular bony peri-implant defects in dog of stem cells group showing thicker interconnected bone trabeculae enclosing relatively wide bone marrow spaces with many osteocytes content.
The sections stained by Masson’s Trichrome showed newly formed
bony trabeculae radiating from the periphery of the cavity towards the center which is filled with granulation tissue with severe collagen fiber’s
reaction in chitosan group and slight maturation of the ingrowing bony
trabeculae with strong collagen fiber’s reaction.
At group 2 H&E sections showed large amount of new trabecular
and lamellar bone was visible. New bone formation occupied a major part
of the defect with large bone marrow spaces, osteocyte content appears
around bone marrow which were haphazardly arranged in chitosan group
while GMSC group showed almost completely attachment of the
trabeculae with formation new Haversian canal surrounded by lamellar
zone and few bone marrow spaces comparing with chitosan group.
The sections stained by Masson’s Trichrome showed in chitosan
group more maturation of many areas of the coalesced bony trabeculae and wide marrow spaces can be seen with mild collagen fiber’s reaction while in GMSCs group showed increased maturation of the compact bone than their counter parts of other groups with few collagen fibers reaction.