Limits...
The effect of perturbations on resistance to sliding in second-order moments comparing two different bracket types.

Wong JK, Romanyk DL, Toogood RW, Heo G, Carey JP, Major PW - J Dent Biomech (2014)

Bottom Line: Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls.However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls.From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, School of Dentistry, Faculty of Medicine & Dentistry, Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB, Canada.

ABSTRACT
Orthodontic literature has shown all ligation methods to behave similarly in the clinical situation; however, the reasoning behind this still requires further investigation. A novel frictional device able to measure forces at the level of the bracket along with a custom perturbation device was used to investigate the effect of perturbations on resistance to sliding (RS) using conventional and passive ligated brackets. 150 3M Victory Series twins (0.022 slot) and 150 Damon Q brackets (0.022 slot) were tested using an 0.018 x 0.025 stainless steel wire for RS. There were 5 test groups consisting of equal numbers (n=30) representing combinations of high and low amplitude and frequency of perturbations along with a control. Second order angulation tested ranged from 0 to 6 degrees. Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls. At 6 degrees, this difference (P<0.001) was seen in both high perturbation groups and one of the low perturbation groups. For passive ligated brackets, no statistically significant difference between groups was seen at 0 degrees. However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls. From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations. Also, amplitude of perturbations has a larger role than frequency in reduction of RS values.

No MeSH data available.


Diagram of the load cell, mounting apparatus, rotation stage.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
getmorefigures.php?uid=PMC4228925&req=5

fig3-1758736014557500: Diagram of the load cell, mounting apparatus, rotation stage.

Mentions: A custom three-dimensional (3D) frictional (Figures 2 and 3) device was designed. The conical load cell adaptor connects the load cell with the test bracket dowel. Both the bracket–dowel sample and conical load cell adaptor have a flat edge which allows reproducible orientations on separate tests. The load cell (Nano 17 SI-50-0.5, ATI Industrial Automation, Apex, NC) is mounted to a programmable micro-adjusting rotating platform (Precision Rotation Platform, PR01, Thor Labs, Newton, NJ) which when turning reproduces second-order movements in the x–z plane. This particular load cell is capable of measuring forces up to 50 N in the x- and z-directions with a resolution of 1/80 N, and up to 70 N in the y-direction with the same resolution. When considering moments, it can measure up to 500 N mm in all three directions with a resolution of 1/16 N mm. There are also two manual translation stages (1/2-in Translation Stage, MT1, Thor Labs, Newton, NJ) that allow for micro-adjustments in the y- and z-axes to allow proper positioning of the wire into the bracket slot. That is, initially, the wire will not engage with the bracket slot. The wire is secured into a programmable linear micro-actuator (M230.10 DC-Mike Actuator, Physik Instrumente (PI) GmbH&Co, Karlsruhe, Germany) which allows the operator the ability to pull the wire along the x-axis at a consistent and constant speed. The micro-actuator and rotating platform are operated by calibrated custom software so that programmed test conditions were exactly repeatable for each bracket.


The effect of perturbations on resistance to sliding in second-order moments comparing two different bracket types.

Wong JK, Romanyk DL, Toogood RW, Heo G, Carey JP, Major PW - J Dent Biomech (2014)

Diagram of the load cell, mounting apparatus, rotation stage.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4228925&req=5

fig3-1758736014557500: Diagram of the load cell, mounting apparatus, rotation stage.
Mentions: A custom three-dimensional (3D) frictional (Figures 2 and 3) device was designed. The conical load cell adaptor connects the load cell with the test bracket dowel. Both the bracket–dowel sample and conical load cell adaptor have a flat edge which allows reproducible orientations on separate tests. The load cell (Nano 17 SI-50-0.5, ATI Industrial Automation, Apex, NC) is mounted to a programmable micro-adjusting rotating platform (Precision Rotation Platform, PR01, Thor Labs, Newton, NJ) which when turning reproduces second-order movements in the x–z plane. This particular load cell is capable of measuring forces up to 50 N in the x- and z-directions with a resolution of 1/80 N, and up to 70 N in the y-direction with the same resolution. When considering moments, it can measure up to 500 N mm in all three directions with a resolution of 1/16 N mm. There are also two manual translation stages (1/2-in Translation Stage, MT1, Thor Labs, Newton, NJ) that allow for micro-adjustments in the y- and z-axes to allow proper positioning of the wire into the bracket slot. That is, initially, the wire will not engage with the bracket slot. The wire is secured into a programmable linear micro-actuator (M230.10 DC-Mike Actuator, Physik Instrumente (PI) GmbH&Co, Karlsruhe, Germany) which allows the operator the ability to pull the wire along the x-axis at a consistent and constant speed. The micro-actuator and rotating platform are operated by calibrated custom software so that programmed test conditions were exactly repeatable for each bracket.

Bottom Line: Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls.However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls.From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, School of Dentistry, Faculty of Medicine & Dentistry, Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB, Canada.

ABSTRACT
Orthodontic literature has shown all ligation methods to behave similarly in the clinical situation; however, the reasoning behind this still requires further investigation. A novel frictional device able to measure forces at the level of the bracket along with a custom perturbation device was used to investigate the effect of perturbations on resistance to sliding (RS) using conventional and passive ligated brackets. 150 3M Victory Series twins (0.022 slot) and 150 Damon Q brackets (0.022 slot) were tested using an 0.018 x 0.025 stainless steel wire for RS. There were 5 test groups consisting of equal numbers (n=30) representing combinations of high and low amplitude and frequency of perturbations along with a control. Second order angulation tested ranged from 0 to 6 degrees. Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls. At 6 degrees, this difference (P<0.001) was seen in both high perturbation groups and one of the low perturbation groups. For passive ligated brackets, no statistically significant difference between groups was seen at 0 degrees. However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls. From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations. Also, amplitude of perturbations has a larger role than frequency in reduction of RS values.

No MeSH data available.