الفهرس 
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Abstract
The purpose of this study was to investigate the influence of geometrical design characteristic on the primary stability of orthodontic miniscrews. Forty self-drilling miniscrews were classified into groups according to manufacturing company; each group contained 10 miniscrews. group I; Tomas® (Dentaurum, Germany), group II; AbsoAnchor® (Dentos, Korea), group III; Hubit® miniscrew (Hubit, Korea), group IV; Creative® (China). All of them had 1.6 mm diameter and 6.0 mm length. Miniscrews were manually inserted perpendicular to bovine bone. The bone sample characteristics were analyzed with cone-beam computed tomography to measure cortical thickness, cortical density and bone marrow density. Each miniscrew was evaluated by a 20.00 kV scanning electron microscope. Then linear and angular measurements were made using Photoshop Software Program. Primary stability was assessed by Periotest and pullout test. The data were then collected and analyzed. All linear and angular measurements of miniscrews showed statistical significant differences between the four groups of miniscrews. The four groups of miniscrews showed statistical significant differences regarding the pullout test. Tomas® achieved the highest value, whereas Creative® achieved the lowest value. There were direct significant correlations between pitch width, flank, thread angle, insertion angle and lead angle and pullout force. Thread shape factor had indirect significant correlation with pullout force and direct significant correlation with periotest value.