In vitro assessment of competency for different lingual brackets in sliding mechanics

Abstract

Aim:To determine the static frictional resistance of different lingual brackets at different second order angulations when coupled with stainless steel (SS) archwire in dry and wet conditions.Materials and Methods:Using a modified jig, frictional resistance was evaluated under different conditions for a total of 270 upper premolar lingual brackets (0.018″ × 0.025″ - conventional - 7th generation and STb, self-ligating – evolution) with no in-built tip or torque together with 0.016″ × 0.022″ straight length SS archwires. For conventional brackets, the archwire was secured with 0.008″ preformed SS short ligature ties.Statistical Analysis:One way analysis of variance with Tukey HSD as post-hoc test was applied for degree wise and bracket wise comparison within dry condition and wet condition. For pair wise comparison Student's t-test was used.Results:Under both conditions the static frictional resistance is significantly higher for self-ligating brackets at 0°, while at 5° and 10° it is higher for 7th generation brackets. Statistically, significant difference does not exist at 0° between conventional brackets and the same was found at 5° and 10° between STb and self-ligating brackets. With an increase in second order angulations, all the evaluated samples exhibited an increased frictional value. Wet condition samples obtained a higher value than their corresponding dry condition.Conclusion:The self-ligating bracket evaluated in this in vitro study is not beneficial in reducing friction during en-mass retraction due to its interactive clip type.

Influence of ligation method on friction resistance of lingual brackets with different second-order angulations: an in vitro study

“…However, several studies with labial brackets and the few existing studies with lingual brackets showed that increasing reduction or friction depended on the ligation method using passive or active self-ligating brackets, conventional or unconventional elastomeric ligatures, metal ligature types, and different wires alloys and gauges. 5 , 8 - 12 , 14 - 18 …”

“… 2 , 11 The brackets with elastic ligatures and PSWb brackets with metal ligature presented the highest resistance to static friction, probably due to their deep slot design, and may offer clinical significance. However, friction-related studies on lingual brackets are still too few to make comparative conclusions, 2 , 12 although Lalithapriya et al 12 showed that self-ligating brackets may not be beneficial in reducing friction during en-mass retraction due to their interactive clip type.…”

“… 4 - 10 However, few studies on friction produced by lingual brackets have been published. 2 , 11 , 12 …”

In-vitro investigation of the mechanical friction properties of a computer-aided design and computer-aided manufacturing lingual bracket system under diverse tooth displacement condition

“…When measuring the frictional forces of the LB system, it is more appropriate to adopt an experimental design that uses the entire dentition set with an initial malocclusion condition, rather than 1 or several LBs lined up in a single row. 10 14 15 16 17 18 19 20 Moreover, there have been few studies involving comparison of the frictional properties of Con-LB, Con-LB with narrow bracket width (Con-LB-NBW), and CAD/CAM-LB. 17 18 19 20 Therefore, the objective of the present in vitro mechanical study was to compare the static (SFF) and kinetic frictional forces (KFF) of CAD/CAM-LB with those of Con-LB and Con-LB-NBW under 3 tooth displacement conditions when drawing a leveling/alignment wire.…”

“… 10 14 15 16 17 18 19 20 Moreover, there have been few studies involving comparison of the frictional properties of Con-LB, Con-LB with narrow bracket width (Con-LB-NBW), and CAD/CAM-LB. 17 18 19 20 Therefore, the objective of the present in vitro mechanical study was to compare the static (SFF) and kinetic frictional forces (KFF) of CAD/CAM-LB with those of Con-LB and Con-LB-NBW under 3 tooth displacement conditions when drawing a leveling/alignment wire. The null hypothesis was that there would be no significant differences in SFF and KFF according to LB types or tooth displacement conditions.…”