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The influence of miniscrew insertion torque

The influence of miniscrew insertion torque
The influence of miniscrew insertion torque

Objective: The aim of this in vitro study was to evaluate the progressive development of surface microdamage produced following the insertion of orthodontic miniscrews (OMs) into 1.5 mm thick porcine tibia bone using maximum insertion torque values of 12 Ncm, 18 Ncm, and 24 Ncm.

Methods: Aarhus OMs (diameter 1.5 mm; length 6 mm) were inserted into 1.5 mm porcine bone using a torque limiting hand screwdriver set at 12 Ncm, 18 Ncm, and 24 Ncm. A custom rig equipped with a compression load cell was used to record the compression force exerted during manual insertion. A sequential staining technique was used to identify microdamage viewed under laser confocal microscopy. Virtual slices were created and stitched together to form a compressed two-dimensional composition of the microdamage. Histomorphometric parameters, including total damage area, diffuse damage area, maximum crack length, maximum damage radius, and maximum diffuse damage radius, were measured. Kruskal-Wallis Tests and Wilcoxon Rank-Sum Tests were used to analyse the generated data.

Results: All OMs inserted using 12 Ncm failed to insert completely, while partial insertion was observed for two OMs inserted at 18 Ncm. Complete insertion was achieved for all OMs inserted at 24 Ncm. Histomorphometrically, OMs inserted using 24 Ncm produced a significantly larger diffuse damage area (P < 0.05; P < 0.05) and maximum diffuse damage radius (P < 0.05; P < 0.05), for both the entry and exit surfaces, respectively, compared with the 12 Ncm and 18 Ncm groups.

Conclusions: Insertion torque can influence the degree of OM insertion and, subsequently, the amount of microdamage formed following insertion into 1.5 mm thick porcine tibia bone. An increase in insertion torque corresponds with greater insertion depth and larger amounts of microdamage.

37-44
Nguyen, Melissa V.
bf880da2-9cc9-4346-9693-bdd5db9c5b1f
Codrington, John
e466f48b-3a22-45cc-81ea-e754a50f0c27
Fletcher, Lloyd
48dca64b-f93c-4655-9205-eaf4e74be90c
Dreyer, Craig W.
83899b11-6621-4c12-815b-d2fd1bc22deb
Sampson, Wayne J.
0e5e3620-b640-4e2d-bdbd-6f1c4c686235
Nguyen, Melissa V.
bf880da2-9cc9-4346-9693-bdd5db9c5b1f
Codrington, John
e466f48b-3a22-45cc-81ea-e754a50f0c27
Fletcher, Lloyd
48dca64b-f93c-4655-9205-eaf4e74be90c
Dreyer, Craig W.
83899b11-6621-4c12-815b-d2fd1bc22deb
Sampson, Wayne J.
0e5e3620-b640-4e2d-bdbd-6f1c4c686235

Nguyen, Melissa V., Codrington, John, Fletcher, Lloyd, Dreyer, Craig W. and Sampson, Wayne J. (2018) The influence of miniscrew insertion torque. European Journal of Orthodontics, 40 (1), 37-44. (doi:10.1093/ejo/cjx026).

Record type: Article

Abstract

Objective: The aim of this in vitro study was to evaluate the progressive development of surface microdamage produced following the insertion of orthodontic miniscrews (OMs) into 1.5 mm thick porcine tibia bone using maximum insertion torque values of 12 Ncm, 18 Ncm, and 24 Ncm.

Methods: Aarhus OMs (diameter 1.5 mm; length 6 mm) were inserted into 1.5 mm porcine bone using a torque limiting hand screwdriver set at 12 Ncm, 18 Ncm, and 24 Ncm. A custom rig equipped with a compression load cell was used to record the compression force exerted during manual insertion. A sequential staining technique was used to identify microdamage viewed under laser confocal microscopy. Virtual slices were created and stitched together to form a compressed two-dimensional composition of the microdamage. Histomorphometric parameters, including total damage area, diffuse damage area, maximum crack length, maximum damage radius, and maximum diffuse damage radius, were measured. Kruskal-Wallis Tests and Wilcoxon Rank-Sum Tests were used to analyse the generated data.

Results: All OMs inserted using 12 Ncm failed to insert completely, while partial insertion was observed for two OMs inserted at 18 Ncm. Complete insertion was achieved for all OMs inserted at 24 Ncm. Histomorphometrically, OMs inserted using 24 Ncm produced a significantly larger diffuse damage area (P < 0.05; P < 0.05) and maximum diffuse damage radius (P < 0.05; P < 0.05), for both the entry and exit surfaces, respectively, compared with the 12 Ncm and 18 Ncm groups.

Conclusions: Insertion torque can influence the degree of OM insertion and, subsequently, the amount of microdamage formed following insertion into 1.5 mm thick porcine tibia bone. An increase in insertion torque corresponds with greater insertion depth and larger amounts of microdamage.

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More information

e-pub ahead of print date: 24 April 2017
Published date: February 2018

Identifiers

Local EPrints ID: 425703
URI: http://eprints.soton.ac.uk/id/eprint/425703
PURE UUID: 7caaa24b-00b9-412f-95cc-be4e18dac65b

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Date deposited: 01 Nov 2018 17:30
Last modified: 01 Nov 2018 17:30

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Contributors

Author: Melissa V. Nguyen
Author: John Codrington
Author: Lloyd Fletcher
Author: Craig W. Dreyer
Author: Wayne J. Sampson

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