الفهرس 
ACKNOWLEDGEMENTOnly 14 pages are availabe for public view
 |  | from | 107 |  |  |
| | | from | 107 | | |
Abstract
One of the challenges facing dentists during preparation of treatment plan is unfavorable loss of the alveolar bone ridge due to different causes, which may cause insufficient bone volume in the horizontal and/or vertical dimensions. The resulting bone defect not only hampers prosthetic reconstruction but also has an aesthetic effects. Therefore, all attempts must be performed to regenerate the lost bone.
The aim of this study is comparing histologically & histomorphometrically the bone healing rate of the combination of hydroxyapatite plus propolis extract versus hydroxyapatite.
The current study was conducted eighteen New Zealand white male rabbits which were acquired from the animal house of Medical Research Institute, Alexandria University.
Rabbits of 5 months of age, with a weighing range about (3–3.5 kilo gram) were included in this study. The rabbits were housed under the identical normal environmental surroundings in the animal house.
The right tibia bone was served as the positive control side and the left tibia bone served as the study side in 12 rabbits. Bilateral bone defects in both tibia were created & left vacant as negative control group in the other six rabbits.
About 4-5cm incision was made by surgical blade in the medial aspect of both rabbit thighs including skin and periosteum. Then, Periosteum was reflected with a periosteal elevator leaving the bone exposed. A Critical Size bone defect 6mm in diameter& 5mm depth was created bilaterally using sterile Trephine bur with profuse saline irrigation to decrease heat generation. The study divided into three groups:
group A (Negative control): Critical size defect (CSD) was created and left empty in the medial side of both right and left tibias of six rabbits only.
Summary
57
group B (Positive control): Hydroxyapatite (HA) was added in the Critical size defect (CSD) in the medial side of the right tibia in the other 12 rabbits.
group C (Study): Hydroxyapatite (HA) plus propolis was added in the Critical size defect (CSD) in the medial side of the left tibia in the other 12 rabbits.
The wound were sutured in layers, with non-absorbable Blue Monofilament polypropylene suture. All rabbits were given antibiotics in the form of Ampicillin 1gm IM immediately after surgery. They were also given medication for 5 days after surgery.
At 3 and 6 weeks postoperatively, six rabbits from the positive control and study groups and three rabbits from the negative control group were euthanized in each scarification period.
After 3 weeks, histological assessment was done, study group revealed thicker trabeculae with more regularly arranged osteocytes and relatively smaller bone marrow spaces than other groups. At 6 weeks, specimens revealed higher percentage of the formed bone in the defect area in both groups. However, in the negative control group, the regenerated bone was lower than in the other groups. Histomorphometrically, the mean percentage of bone surface area in study group was higher than positive control group through all experimental periods.
Our research found that employing propolis in bone regeneration yielded better results.
Propolis represents the next step in the evolution of bone regeneration. The propolis solved both extended bone healing time and delaying the treatment plan problems, and open a new age for the use of propolis as grafting material. It accelerates bone regeneration and offers a very good stable bone surface.