* Eman Saad Radwan Ali, ** Mona Abdelaziz Montasser, *** Ahmed Maher Fouda * BDent, Faculty of Dentistry, Mansoura University. ** Associate Professor of Orthodontics, Department of Orthodontics, Faculty of Dentistry, Mansoura University. *** Lecturer of Orthodontics, Department of Orthodontics, Faculty of Dentistry, Mansoura University. Abstract: Aim: The aim of this review is to provide the orthodontists with collected information about the effect of geometrical design characteristic on the primary stability of orthodontic miniscrews. Methods:The Pubmed and Google scholar were searched for articles about the differences between primary and secondary stability of miniscrews, factors affecting primary stability and different methods of measuring primary stability. Conclusion: Geometric design characteristics of miniscrew implants significantly affect their primary stability. Increase pitch width, flank, thread angle, insertion angle and lead angle of miniscrew implant significantly affects pullout force and hence achieves better primary stability. Decrease thread shape factor significantly increases pullout force and decreases periotest value resulting in better primary stability. Key words:primary stability, pullout test, orthodontic miniscrew implants. Contents: 1.Introduction 2. Success rate of temporary anchorage device  3. Factors affecting primary stability 3.1. length of miniscrew 3.2. Diameter of miniscrew 3.3. Thread shape factor 3.4. Thread depth 3.5. Thread pitch 4. Methods of measuring primary stability 5.Conclusion 6.Refrences