الفهرس 
Review Of literatureOnly 14 pages are availabe for public view
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Abstract
The potentiality of hard tissue formation in furcation perforation using stem cells in animals was evaluated in this study .This study utilized six male adult healthy mongrel dogs. The mandibular first molar teeth were bilaterally extracted in each dog as a source for dental pulp stem cells and transported to the laboratory for stem cell harvesting and culturing.
Dental pulp was and removed washed then minced into 2x2x1 mm fragments using a sterile scalpel, then digested by collagenase enzyme type I to acquire a cells that were cultured and incubated at 37C in 5 % CO2 and monitored every day for need of change of culture medium. Day 8 cells were collected.
Collagraft Bone Graft Matrix Strip sterile in 2mm length x2 mm width x2 mm height impregnated with DPSCS of cell density 5x106 and DMP1was used to repair a freshly induced furcation perforation after endodontic root canal treatment in the premolars P2, P3 and P4 premoalrs and second molar teeth in each of the two quadrants. Right Mandibular second premolar P2 was used as a negative control group and Left Mandibular second premolar P2 was used as a positive control group in each dog. Teeth were restored and the animals were followed up for observation periods one month (2 dogs), two months (2 dogs) and three months (2 dogs).
At the end of every observation period the dogs were sacrificed and the mandibles were surgically dissected, cut
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and prepared for sectioning, staining and diagnosis. Sections were stained with hematoxylin and eosin (H&E) Masson’s trichrome stain and Alizarin Red and Parameters were evaluated through the three observation periods.
Inflammatory cell count for Hematoxylin and Eosin slide in the three groups was counted using image analysis software. Data were collected, tabulated and a grade scoring was used according to Samiee et al.,(13) Grade 0: No inflammatory cells Grade 1: inflammatory cells < 25 Grade 2: inflammatory cells =25-50 Grade 3: inflammatory cells =51-75 and Grade 4: inflammatory cells > 75
Presence or absence of hard tissue bridge in All Alizarin Red stained slides was recorded and tabulated as scores; Score 0 absent and Score 1 present.
Area fraction of newly formed hard tissue in Masson trichrome stained slide. Total Area fraction of newly formed hard tissue was measured using image analysis software
Bone or Tooth hard tissue resorption in all Hematoxylin and Eosin, Masson’s Trichrome and Alizarin red stained slides of the three groups were examined for bone or hard tissue resorption.
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Histopathological changes in all stained slides were recorded as the type of cells present and the type of tissue formed through the three observation periods and described.
Data was presented as means and standard deviation values that were statistically analysed using statistical analysis software SPSS* .ANOVA test was used for parametric variables .Turkey post hoc tests were used in case of significance. Fisher exact test was used for non numeric values.
Results For the inflammatory cell count showed that the negative control groups through the three observation periods showed the least inflammatory score means, followed by the experimental groups except for group I then followed by the positive control groups. Only in group I (1month) positive control group had the highest mean score None of the experimental groups through the three observation periods was free from inflammatory cells and that there is no significant difference present between the three observation periods. The dominant inflammatory score that was obvious in most groups was Grade 1 and the least inflammatory score recorded was Grade 3.
Results for presence or absence of hard tissue bridge showed that dentin matrix protein and dental pulp stem cells impregnated scaffold caused hard tissue tissue formation in the furcation perforation area in100% of samples of experimental groups II and III and 66.7% of samples of
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experimental group I and the presence of a significant difference between groups II and III and group I.
Results for Area fraction of newly formed hard tissue showed that all experimental samples had new hard tissue formed within the tissue at the furcation perforation site. The lowest mean percentage was recorded by experimental group I followed by group II then Experimental group III With a significant difference present between group III and both of groups I and II.
Bone or Tooth hard tissue resorption evaluation showed that none of the samples either positive , negative or experimental showed any signs bone or tooth hard tissue resorption.
Histopathological changes in all stained slides showed that negative control samples showed normal organized bone architecture with trabeculae and haversian system normal periodontal ligaments. The positive control groups along the three observation periods showed presence of blood vessels and edema. Inflammatory cells detected were of a chronic nature (plasma cells and lymphocytes) Samples of the positive groups also showed varying degrees of epithielium and well organized fibrous granulation tissue formed at the perforation site. The experimental groups showed presence of chronic inflammatory cell infiltration in the new tissue formed at the furcation perforation site but of varying grades of inflammation from Grade 1 to 3. 100% of the experimental samples showed new hard tissue formed at
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the furcation perforation site with varying degrees in the three groups that increased in group III. Even when samples showed grades of inflammatory cell count, still it had hard tissue deposits where the areas of inflammation had subsided closer to the perforation site.
The hard tissue formed was mainly acellular deposits of globular pattern scattered throughout the granulation tissue formed at the furcation perforation site similar to the formation of primary dentin. Most calcifications started around the vessels and along the collagen fibers in the tissue that enlarged along the groups and fused to form acellular patterned deposits. Some samples showed formation of areas of hard tissue with cellular areas in it similar to osteodentin formation through the granulation tissue in the perforation site.
the experimental samples showed hard tissue bridge at the perforation site on top of the tissue formed.11.1% of the experimental samples showed no hard tissue bridge formation although they showed deposits inside the tissue formed at the perforation site These samples showed either nothing or showed epithelium overlying the tissue in the perforation site .