Deepak, C (2013) Evaluation of peak insertion torque and dimensional changes of miniscrew implant of varying diameters in different cortical bone thickness: An in-vitro study. Masters thesis, Ragas Dental College and Hospital, Chennai.
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Abstract
AIM : The purpose of this study was to evaluate the peak insertion torque of varying diameters of miniscrew implants in different cortical bone thickness and to assess the dimensional changes, distortion and fracture of the retrieved miniscrew implants. MATERIALS AND METHODS : Seventy two self-drilling MSI’s (SK company, India) of varying diameters (1.2mm,1.3mm,1.4mm and 1.5mm) were inserted into synthetic bone of different cortical thickness (1mm, 2mm and 3mm). The peak insertion torque values for each MSI were recorded. All the MSI’s were retrieved and assessed for dimensional changes, distortion and fracture, both macroscopically and under scanning electron microscope. RESULTS : The mean peak insertion torque recorded for the 1.2mm, 1.3mm, 1.4mm and 1.5mm were 7.02Ncm, 8.06Ncm, 10.02Ncm and 11.37Ncm respectively. The mean peak insertion torque recorded for the 1mm, 2mm and 3mm cortical bone thickness were 7.66Ncm, 9.06Ncm and 10.64Ncm respectively. The retrieved smaller diameter MSI’s(1.2mm,1.3mm) showed, fatigue striations at the tips, threads and shaft core, blunting of the tips and threads, distortion and fracture at the thread shaft interface when inserted into thicker cortical bone(3mm). CONCLUSION : As the diameter of the MSI’s and the cortical bone thickness increases, the peak insertion torque increases proportionately. When using a smaller diameter MSI’s in dense cortical bone, a pilot drill will prevent the increase in the peak insertion torque and hence decrease the surface dimensional changes and improve the efficacy of the MSI’s.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Miniscrew implant, Cortical bone thickness, Peak insertion torque, Dimensional changes, Distortion, Fracture. |
| Subjects: | DENTAL > Orthodontics and Dentofacial Orthopedics |
| Depositing User: | Subramani R |
| Date Deposited: | 04 Sep 2017 03:38 |
| Last Modified: | 12 Nov 2017 14:52 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/2909 |
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