الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 137 |  |  |
| | | from | 137 | | |
Abstract
This study was aimed to test the influence of platelet rich fibrin on osseointegration of titanium implants initially stabilized in osteotomy sites with 2 different microgaps. The objectives of this study were to examine the influence of PRF used for filling the critical sized microgaps in implant-host beds receiving initially stabilized pure titanium implant by proliferation and differentiation of peri-implant cells, particularly osteoblasts. Three male adult dogs ranging in age from 12 to 18 months with mean weight 10 kilograms and 12 pure titanium implant fixtures (3.3 mm in diameter and 8 mm in length) were used in this study. In each animal the right and left tibiae were destined to receive 2 implants fixtures (8mm in length and 3.3 mm in diameter), 1 proximally and 1 distally inserted in the medial aspect of each tibia and spaced 5 mm apart. Osteotomy sites were created using dental implant drills. The upper 5mm of the proximal osteotomy sites were widened by the next caliber drill (3.75 mm in diameter) to create peri-implant defect size of 0.45 × 5.0 mm (width × length) in the right tibiae, and by the next caliber drill (4.5 mm in diameter) to create peri-implant defect size of 1.2 × 5.0 mm (width × length) in the left tibiae. After preparation of the osteotomy sites and before fixture installation, each osteotomy site was filled with the prepared PRF, and then fixtures’ installations at 25 N/Cm2 were done to achieve initial stability. The distal osteotomy sites were drilled in the same manner as the proximal ones but fixtures installations were done without prior placement of PRF. Microstructural evaluation was performed by using both scanning electron microscope and light microscope. Scanning electron microscopic examination of bone implant interface without using PRF revealed that most of the area of the pure titanium implant surface was not in direct contact with the newly formed calcified bone matrix and bone trabeculae, while with the use of PRF most of the area of the pure titanium implant surface was in direct contact with the newly formed calcified bone matrix and mature bone trabeculae. Light microscopic examination illustrated close adaptation of bone tissues to the pure titanium implant surface with the use of PRF by formation of collagen fibers, calcified bone matrix and more mature and regular bone trabeculae around pure titanium implant. However, without the use of PRF there was a gap (space) between implant and bone tissues. These gaps were filled by collagen fibers, calcified bone matrix and little mature and irregular bone trabeculae formation in some areas and absence of this formation in other areas around the pure titanium implant. Based on the results of this study, it can be concluded that: 1. Procuring PRF is an easy, simple, and cost-effective procedure. 2. Osseointegration of the initially stabilized pure titanium implants placed in osteotomy sites prepared with 2 different microgaps was qualitatively more rapid with PRF than without PRF. 3.The proposed role of PRF altogether with its effect on the proliferation and differentiation of peri-implant cells is still in need of further clarification using different large sized microgaps.