title: Insertion torque, pull-out strength and cortical bone thickness in contact with orthodontic mini-implants at different insertion angles.
abstract: This study aimed to evaluate biomechanical behaviour of inclined orthodontic mini-implants by analyzing its insertion torque (IT), axial pull-out strength (APS), and cortical bone thickness in contact with mini-implant (CBTC). A total of 102 mini-implants were inserted at 90 degree, 60 degree, and 45 degree to the surface of synthetic bone. Peak IT was measured, and the mini-implants were aligned with the mechanical testing machine to record the APS. The cortical bone thickness in contact with each mini-implant was measured after the pull-out test and the data were subjected to statistical analyses. The 45 degree group had a significantly higher IT compared with the 90 degree group (P < 0.05). There was a statistically significant increase in the average of cortical bone thickness in CBTC across the three groups (P < 0.05). A negative correlation between the angulation and the CBTC (r = -0.95, P < 0.05) and a positive correlation between the APS and the CBTC were observed (r = 0.34, P < 0.05). Mini-implants that are inserted more inclined to the surface of the bone provide greater IT and an increased contact with the cortical bone. The greater the CBTC, the greater is the APS.
authors: * Graduate Dentistry Program, Orthodontics, Pontifical Catholic University of Paraná.
authors: Thiago Martins
authors: TM
authors: Meira
authors: Orlando Motohiro
authors: OM
authors: Tanaka
authors: Maiara Medeiros
authors: MM
authors: Ronsani
authors: Ivan Toshio
authors: IT
authors: Maruo
authors: Odilon
authors: O
authors: Guariza-Filho
authors: Elisa Souza
authors: ES
authors: Camargo
authors: Hiroshi
authors: H
authors: Maruo
mesh_terms: D001842:Bone and Bones; D015921:Dental Implants; D006801:Humans; D052280:Orthodontic Anchorage Procedures; D016382:Orthodontic Appliance Design; D019415:Torque
chemical_list: D015921:Dental Implants