الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Immediate post-extraction implant placement offers a shorter treatment period and reduced number of surgical interventions. In addition, it minimizes the marginal mucosal recession and promotes esthetic outcome. However, due to the mismatch between the diameters of both implant and extraction socket, a gap develops. Bone substitutes have been commonly used to fill the gap to prevent bone resorption. Recently, there is a trend towards using bone modulating materials to fill this defect, such as simvastatin which showed an ability to induce bone regeneration when applied either systemically or locally.
The aim of this randomized controlled clinical study was to evaluate the effect of locally applied simvastatin on bone formation in the jumping distance around immediately placed dental implants using cone beam computed tomography (CBCT).
This randomized controlled clinical study followed the split-mouth design. Ten patients were selected for this study. Each patient presented with two bilateral non-restorable teeth, in the maxillary canine-premolar region, that were indicated for extraction and requiring placement of two immediate dental implants. Atraumatic extraction protocol was followed, then dental implants were inserted immediately in the extraction sockets in a palatal direction and submerged apical to the bone crest. Each of the two sides was randomly assigned to one of the following two study groups:
-Simvastatin group: in which simvastatin on solid lipid nanoparticles was injected in the jumping distance between the implant and the socket inner walls.
-Placebo group (control group): in which simvastatin carrier (solid lipid nanoparticles) was injected solely in the jumping distance between the implant and the socket inner walls.
CBCT was performed to all patients immediately after the surgery. A series of measurements were made using CBCT computer software to determine the dimension of the buccal bone plate, the jumping distance, the horizontal dimension between the implant surface and the outer surface of the buccal bone and the relation between the buccal alveolar crest and the implant platform. After 3 and 6 months of healing, CBCT was repeated to detect the bone density buccal to the implants. In addition, the amount of gap fill and the alteration in the dimension of bone were further measured. The wound healing index (WHI) was used to clinically detect any adverse effect caused by the drug or the carrier on the healing of both the soft and hard tissues. Data was collected and statistically analyzed (P=0.05).
All implants were osseointegrated during the follow-up periods. The WHI was similar in both groups in the first week (1.3 ± 0.48) and was described as mild pain. At the second week, the WHI returned to 1 in both groups. At baseline, the CBCT examination showed that the buccal bone wall was significantly thicker in the placebo group than in the simvastatin group. While the vertical and horizontal gap dimensions, the distance between the surface of the implant and the outer surface of the buccal wall (S-OC), and the distance between the implant platform and buccal alveolar crest (IP-C) were statistically similar in both groups at baseline. At 3 and 6 months, CBCT examination showed complete resolution of the gap in both simvastatin and placebo groups. The horizontal ridge reduction was significantly greater at the 3rd month compared to the 6th month, in both groups. However, the amount of ridge reduction in both groups at each follow-up period was statistically similar. Moreover, the buccal alveolar crest showed statistically similar degree of resorption in both groups at each follow-up period. Yet no implant exposure was detected. Simvastatin led to a significant increase in the density of the newly formed bone around the immediate dental implant at both 3- and 6-month follow-up.