الفهرس 
ACKNOWLEDGEMENTSOnly 14 pages are availabe for public view
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Abstract
The present study was conducted to evaluate histologically and morphometrically the effect of Nigella sativa oil and powder on the process of extraction socket healing in rabbit model.
This study was carried out on 24 healthy adult male rabbits. A split mouth design was used in this study, the lower right and left first premolars were extracted under general anesthesia. All the right sockets were left for normal healing as the control group. The left sockets were considered the study groups. They were treated with nigella sativa powder in half of the animals while in the other half Nigella sativa oil was used. The animals were divided equally to be sacrificed after 2 and 4 weeks.
After scarification the mandibles were dissected out, sectioned in two halves, fixed in 10 % buffered neutral formalin and decalcified in 5% trichloroacetic acid, washed, and dehydrated in ethanol and embedded in paraffin wax. Serial bucco-lingual section sections were cut and stained with Hematoxylin & Eosin and Gomori’s trichrome stain. Histomorphometric analysis using Image J software was done to measure the percentage of the surface area of the newly formed bone in the extraction socket in different groups at different observational periods.
1- Histological results
Results of the first observation period (two weeks postoperatively)
A) Control group: The extraction socket showed newly formed thin bone trabecuale extending from the socket walls intermingled with fibrous tissue of limited blood supply. The newly formed woven bone was outlined by a layer of inactive osteoblast cells and contained moderate density of osteocytes.
B) Nigella sativa powder group:The socket was occupied by higher amount of newly formed bony trabeculae of variable thickness enclosing marrow spaces of dense connective tissue and profound blood supply. The bone trabeculae were lined by a layer of active plump osteoblast cells and accommodated greater amount of osteocytes than in the control group. Osteointegration line was clearly seen between the native and newly formed bone.
C) Nigella sativa oil group:the results of this group was showed greater amount of newly formed bone compared to the previous two groups. The newly formed trabeculae appeared thick, well organized and showed high cellular activity. It was lined by a continuous layer of voluminous osteoblast cells. And it contained high density of large osteocytes.Bone marrow appeared with highly dense connective tissue and large dilated blood vessels engorged with RBC’s. Also, the newly formed bone exhibited a complete line of osteointegration with the native bone.
Results of the second observation period (four weeks postoperatively)
A) Control group:In this interval, the sockets were almost completely filled with anastomosing bone trabeculae of variable thickness. The newly formed bone accomodated rich osteocyte content,and lined by continuous active osteoblast cells. Fibrous tissue with many dilated blood vessels occupied the spaces between the bone trabeculae. Evident line of osteointgeration was found between the native and new bone.
B) Nigella sativa powder group: the healing features regarding the amount and the organization of the newly formed bone appeared better than in the control group. It consisted of broad masses of trabecular bone with some areas of primary osteons. Great aggregates of well-organized osteocytes, and active osteoblast lining could also be seen on the surface of the bone trabeculae.Complete osteointegration between the new bone and native bone was seen at the lateral walls of the socket.
C) Nigella sativa oil group: the socket was almost filled with dense masses of compact and trabecular bone. The compact bone showed an advanced stage of maturation with numerous haversian systems enclosing central haversian canals.Both compact and trabecular bone revealed a good number of well organized entrapped osteocytes as well as a prominent osteoblast lining.
2- Histomorphometric analysis results
In both observational periods, it was noted that the mean percentage of the newly formed bone in the socket was lowest in the control group followed by Nigella sativa powder group while, Nigella sativa oil group showed the highest values. The difference in percentage of newly formed bone was statistically significant between control group and both of the study groups (Ns powder and oil).
Only at the first observational period the difference between Nigella sativa powder and Nigella sativa oil group was statistically significant while, in the second observational period the difference in the percentage of new bone formation between these two groups was not statistically significant.