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Micro-computed tomographic analysis of bone healing subsequent to graft placement

by Chopra, Preeti M.

Abstract (Summary)
A MicroCT analysis of bone healing subsequent to graft (tri calcium phosphate/TCP) placement in the maxillary sinus prior to dental endosteal implant placement was the objective of the current study. Ten trephined rod shaped human bone cores were obtained three months after the placement of particulate graft material and the samples were stored immediately in 10% neutral buffered formalin. Using a Microcomputed tomography, the samples were evaluated at resolutions of 6 and 20µm. The thresholds for bone and graft material were determined using visual image, intensity (grey level) and histogram analyses. The graft and bone threshold was 235 greylevel and only graft threshold was 600 greylevel magnitudes. The volume, density and threedimensional micro-architecture like trabecular thickness (Tb Th), trabecular separation (Tb sp), structural model index (SMI), trabecular number (Tb no), and connectivity density of the bone and graft material were analyzed using the instrument software. The results were analyzed statistically, using the paired Student’s T-test, with p < 0.05 indicating statistical significance. The graft threshold at 20µm was altered to a 500 greylevel magnitude and the results compared to results obtained at 6µm resolution (graft greylevel magnitude being 600). Eight of the ten samples were prepared as nondecalcified sections and stained with toluidine blue and methylene blue/ basic fuchsin stain, for histological examination. ii The MicroCT images at 6 and 20µm resolutions exhibited different grey scale magnitudes for both bone and graft allowing a definitive differentiation and quantification of the two sample regions. The mean bone volume was more than mean graft volume, that is, 23.8mm3 and 25.5mm3 bone volume versus 2.2mm3 and 2.0 mm3 graft volume at 6 and 20 µm resolutions respectively. Comparison of 6 and 20 µms, showed a significant difference in the graft volume (p=0.0120) and density (p=0.0001). Altering the graft threshold at 20µm to 500 and comparing the results to 6 µm showed a significant difference in graft density. (p=.0001) but difference were not significant for graft volume. The structural data from 2 and 3 dimension images provided a valuable assessment of the graft distribution, its relation to modeling bone and also the nature of the healing bone. The histological examinations showed anticipated cellular activity, osteoid formation and presence of uniformly mineralized trabecular bone, without any significant foreign body response. iii
Bibliographical Information:

Advisor:

School:University of Alabama at Birmingham

School Location:USA - Alabama

Source Type:Master's Thesis

Keywords:bone regeneration transplantation dental implants stress analysis tomography x ray computed wound healing

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