Torque and mechanical failure of orthodontic micro-implant influenced by implant design parameters.
- Author:
Wonjae YU
1
;
Hee Moon KYUNG
Author Information
1. Department of Orthodontics, School of Dentistry, Kyungpook National University, Korea. hmkyung@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Orthodontic micro-implant;
Design parameter;
Torque;
Torsional failure
- MeSH:
Daegu;
Torque*
- From:Korean Journal of Orthodontics
2007;37(3):171-181
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
OBJECTIVE: The present study was aimed at an analytical formulation of the micro-implant related torque as a function of implant size, i.e. the diameter and length, screw size, and the bony resistance at the implant to bone interface. METHODS: The resistance at the implant to cancellous bone interface (S(can)) was assumed to be in the range of 1.0-2.5 MPa. Micro-implant model of Absoanchor (Dentos Inc. Daegu, Korea) was used in the course of the analysis. RESULTS: The results showed that the torque was a strong function of diameter, length, and the screw height. As the diameter increased and as the screw size decreased, the torque index decreased. However the strength index was a different function of the implant and bone factors. The whole Absoanchor implant models were within the safe region when the resistance at the implant/cancellous bone (= S(can)) was 1.0 or less. CONCLUSION: For bone with S(can) of 1.5 MPa, the cervical diameter should be greater than 1.5 mm if micro-implant models of 12 mm long are to be placed. For S(can) of 2.0 MPa, micro-implant models of larger cervical diameter than 1.5 mm were found to be safe only if the endosseous length was less than 8 mm.
