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

Abstract

Objective: To evaluate stainless steel archwire static friction in active and passive self-ligating lingual and conventional brackets with second-order angulations. Methods: Two conventional lingual brackets for canines (STb light/Ormco; PSWb/Tecnident), and two self-ligating brackets, one active (In-Ovation L/GAC) and the other passive (3D/ Forestadent), were evaluated. A stainless steel archwire was used at 0°, 3° and 5° angulations. Metal ligatures, conventional elastic ligatures, and low friction elastic ligatures were also tested. A universal testing machine applied friction between brackets and wires, simulating sliding mechanics, to produce 2-mm sliding at 3 mm/minute speed. Results: Two-way analysis of variance demonstrated a significant effect of the interaction between brackets and angulations (p < 0.001). Tukey test indicated that the highest frictional resistance values were observed at 5° angulation for In-Ovation L, PSWb bracket with non conventional ligature, and STb bracket with metal ligature. As for 3D, PSWb with conventional or metal ligatures, and STb brackets with non conventional ligature, showed significantly lower static frictional resistance with 0° angulation. At 0° angulation, STb brackets with metal ties, In-Ovation L brackets and 3D brackets had the lowest frictional resistance. Conclusions: As the angulation increased from 0° to 3°, static friction resistance increased. When angulation increased from 3° to 5°, static friction resistance increased or remained the same. Self-ligating 3D and In-Ovation L brackets, as well as conventional STb brackets, seem to be the best option when sliding mechanics is used to perform lingual orthodontic treatment.

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

“…This study compared the frictional properties of the CAD/CAM-LB (Incognito) with those of Con-LB and Con-LB-NBW (7G and STb). The findings that the Con-LB-NBW (STb) group showed lower SFF and KFF than the Con-LB (7G) group and the CAD/CAM-LB (Incognito) group under the 3 displacement conditions ( p < 0.001; Table 2 and Figure 5 ) were identical with the results of previous studies, 10 17 18 suggesting that differences in bracket type, bracket width, and ligation method are the main causes of differences in SFF and KFF among these LBs.…”

“…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.…”

Debonding forces of different pads in a lingual bracket system

“…Group 1 (n= 20) received personalized extended pads made of Transbond XT composite resin (3M Unitek, Monrovia, California, USA) and Group 2 (n = 20), metal pads. The area was standardized by measuring the greatest vertical and horizontal length of each lingual face of all premolars used, by means of the calculation A = π R 2 . Then, the total area (28.66 mm²) average was used as the default (7.06 mm²) (Fig 1).…”

“…The lingual technique offers significant aesthetic advantages for patients submitted to orthodontic treatment, and therefore demands continuous development of brackets 1 , 2 and related materials, aiming to obtain results similar to those from conventional labial orthodontic treatment. 3…”