Journal of Pharmacy And Bioallied Sciences
Journal of Pharmacy And Bioallied Sciences Login  | Users Online: 1741  Print this pageEmail this pageSmall font sizeDefault font sizeIncrease font size 
    Home | About us | Editorial board | Search | Ahead of print | Current Issue | Past Issues | Instructions | Online submission




 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 13  |  Issue : 6  |  Page : 1434-1441  

Evaluation of frictional forces generated between three different ligation methods with four different sizes of orthodontic archwires: An In vitro study


1 Department of Orthodontics, Vinayaka Mission's Sankarachariyar Dental College, Salem, Tamil Nadu, India
2 Department of Preventive Dental Sciences, College of Dentistry, Gulf Medical University, Ajman, UAE
3 Department of Oral and Maxillofacial Surgery and Diagnostic Sciences, College of Dentistry, King Faisal University, Al Ahsa, Saudi Arabia
4 Department of Oral Medicine Diagnosis and Radiology, Kalinga Institute of Dental Sciences, KIIT University, Bhubaneshwar, Odisha, India
5 Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin Abdul Aziz University, Alkharj, Saudi Arabia
6 Department of Conservative Dentistry and Endodontics, Vinayaka Mission's Sankarachariyar Dental College, Salem, Tamil Nadu, India

Date of Submission25-Mar-2021
Date of Decision27-Mar-2021
Date of Acceptance03-Apr-2021
Date of Web Publication10-Nov-2021

Correspondence Address:
Ranganathan Rathinasamy
Department of Orthodontics, Vinayaka Mission's Sankarachariyar Dental College, Salem, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jpbs.jpbs_244_21

Rights and Permissions
   Abstract 


Aim: This in vitro study was done to evaluate and compare the frictional forces produced by a passive self-ligating bracket (SLB) and two types of elastomeric ligatures (unconventional elastomeric ligatures [UELs] and conventional elastomeric ligatures [CELs]) on a conventional bracket used with four types of wires. Materials: In this in vitro study, 8 numbers of conventional preadjusted edgewise appliance stainless steel brackets and 4 numbers of passive SLBs were tested. Four types of archwires and two types of ligatures were tested. Brackets were divided into three groups – Group I, Group II, and Group III. All the three groups were further divided into four subgroups based on different archwires. Methods: Custom-made mounting jig was specially constructed for this study – upper member and lower member. After the samples were mounted, traction test was conducted using universal testing machine and readings were tabulated for all specimens. The variables in each group were subjected to one-way analysis of variance. Results: All the three groups were tested for its total friction, static friction, and kinetic friction. SLBs showed a static mean little lower and had kinetic mean little greater than conventional bracket with unconventional module. Conclusion: UELs on conventional brackets and SLBs are able to produce lower frictional force when compared with CELs on conventional brackets.

Keywords: Elastomeric ligatures, frictional resistance, self-ligating brackets


How to cite this article:
Rathinasamy R, Vannala V, Mahabob N, Bhuvaneshwari S, Sam G, Ganapathy A. Evaluation of frictional forces generated between three different ligation methods with four different sizes of orthodontic archwires: An In vitro study. J Pharm Bioall Sci 2021;13, Suppl S2:1434-41

How to cite this URL:
Rathinasamy R, Vannala V, Mahabob N, Bhuvaneshwari S, Sam G, Ganapathy A. Evaluation of frictional forces generated between three different ligation methods with four different sizes of orthodontic archwires: An In vitro study. J Pharm Bioall Sci [serial online] 2021 [cited 2022 Jun 26];13, Suppl S2:1434-41. Available from: https://www.jpbsonline.org/text.asp?2021/13/6/1434/330033




   Introduction Top


High frictional force that occurs between the guiding archwire and the bracket gives a negative treatment outcome. By controlling the friction at the bracket/archwire/ligature interfaces, lower levels of force can be applied during orthodontic treatment to obtain an optimal biological response for effective orthodontic tooth movement. Tweeny and Hughes in 1961 defined friction as the resistance to motion, when it is attempted to slide one surface over another with which it is in contact.

There are many factors that influence frictional forces during orthodontic tooth movement.[1] The method of archwire ligation seemed to be an important factor in friction generation, yet there are only a few studies to confirm the above fact. Elastomeric modules are economical and can be applied fast and are comfortable. Reduction of frictional force can be obtained by stretching the elastomeric ligature by double diameter; elastomeric ligature can be placed in conventional figure of “0” pattern or figure of “8” pattern.[2]

Self-ligating brackets (SLBs) were introduced in the mid-1930s. SLBs showed very less friction, but it varied depending on the type of self-ligating system used – active or passive. Passive SLBs offer more freedom for teeth to move to their natural position even though they are still interconnected because the archwire is never tightly engaged with the bracket slot.[3]

This in vitro study was done to evaluate and compare the frictional forces produced by a passive SLB and two types of elastomeric ligatures (unconventional elastomeric ligatures [UELs] and conventional elastomeric ligatures [CELs]) on a conventional bracket used with four types of wires.


   Materials Top


Two types of upper premolar brackets were used: [Figure 1] (1) conventional preadjusted edgewise appliance stainless steel (SS) bracket (Gemini, 3M Unitek) 8 numbers and (2) passive SLBs (SmartClip, 3M Unitek) 4 numbers. Four types of archwires are tested: (1) 0.014” nickel–titanium (NiTi) wire, (2) 0.016” NiTi wire, (3) 0.017” × 0.025” SS wire, and (4) 0.019” × 0.025” SS wire. In this study, two types of ligatures are used: [Figure 2] (1) conventional ligature-silver medium (3M Unitek) and (2) unconventional ligature-silver medium (Leone Orthodontic Products, Italy). Instron Universal Testing Machine (LLOYD) L. R-50K was used to test the frictional resistance.
Figure 1: A) Conventional PEA stainless steel upper premolar brackets, B) Passive self-ligating upper premolar brackets – SmartClip 3M Unitek).

Click here to view
Figure 2: A)Conventional modules – silver medium (3M Unitek), B) Unconventional modules – silver medium

Click here to view



   Methods Top


Brackets were divided into three groups:

  • Group I: Conventional brackets to be ligated with unconventional modules
  • Group II: Conventional brackets to be ligated with conventional modules
  • Group III: Passive SLBs [Figure 1].


All the three groups were further divided into four subgroups. They are

  1. 0.014” NiTi
  2. 0.016” NiTi
  3. 0.017” × 0.025” SS
  4. 0.019” × 0.025” SS.


Specimen preparation (lower member) [Figure 3]
Figure 3: Lower member

Click here to view


Custom-made mounting jig was specially constructed for this study. An 8-mm/6-mm thickness steel rod was customized and was cut into four pieces having a length of 75 mm. They were welded together in the shape of “P” with one side open, finished, and polished to have a smooth surface. Two little vertical holes were drilled on the upper and lower part of the “P-” shaped jig for the wire to enter, and two horizontal holes were drilled and threaded for two screws to tighten the wire once entered. This custom-made apparatus will be further called as lower member, to be clamped on the immovable clamp of the universal testing machine.

Specimen preparation (upper member) [Figure 4]
Figure 4: Upper member

Click here to view


Steel rod with dimension of 8-mm/6-mm thickness and 100-mm length was cut, finished, and polished to have a smooth surface. This will be used for welding the bracket for each group and subgroups. This will be further called as upper member, to be clamped on the movable clamp of the universal testing machine.

Care was taken to make the vertical hole in a position so that bracket-fixed upper movable clamp ligated with the wire will be passive.

Specimen preparation[Figure 5]
Figure 5: JIGS mounted on Instron

Click here to view


These brackets of each group were welded on the center of the upper member (4 numbers), such that archwires can slide passively with the bracket. Tests were carried out in Composite Technological Park, Kengeri (Bangalore), by using Instron Universal Testing Machine (LLOYD) L. R-50K-England [Figure 6].
Figure 6: Universal testing machine – Instron (LLYOD-50K)

Click here to view


Evaluation of friction for conventional brackets with unconventional modules (Group I)

The custom-made lower member was clamped tightly to the immovable lower clamp of the universal testing machine. Each upper member for Group I was attached to the upper movable clamp of the universal testing machine, and was tested for friction with four wires (0.014” NiTi, 0.016” NiTi, 0.017” × 0.025” SS, and 0.019” × 0.025” SS). Care was taken so that the archwire/bracket/ligature system passive.

Each four bracket wire and unconventional module combination was tested for ten trials (wire and modules changed for each trial) to minimize the influence of elastic deformation..

Evaluation of friction for conventional brackets with conventional modules (Group II)

The custom-made lower member was clamped tightly to the immovable lower clamp of the universal testing machine. Each upper member for Group II was attached to the upper movable clamp of the universal testing machine, and was tested for friction with four wires (0.014” NiTi, 0.016” NiTi, 0.017” × 0.025” SS, and 0.019” × 0.025” SS). Care was taken so that the archwire/bracket/ligature system passive.

Each four bracket wire and conventional module combination was tested for ten trials.

Evaluation of friction for passive self-ligating brackets (Group III)

The custom-made lower member was clamped tightly to the immovable lower clamp of the universal testing machine. Each upper member for Group III was attached to the upper movable clamp of the universal testing machine, and was tested for friction with four wires (0.014”NiTi, 0.016” NiTi, 0.017” × 0.025” SS, and 0.019” × 0.025” SS). Care was taken so that the archwire and SLB system were passive.

Each passive SLB wire combination was tested for ten trials. After the samples were mounted, traction test was conducted, and readings were tabulated for all specimens.

Traction test

Each traction test was conducted at a speed of 6 mm/min over a distance of 9.5 mm, and the following frictional forces were recorded for static friction and kinetic friction at 5 mm, 7 mm, and 9 mm by a universal testing machine. All measurements were performed under dry condition at temperature 20°C ± 2°C.


   Results Top


All the three groups were tested for its total friction, static friction, and kinetic friction. Each group with its mean, static mean, and kinetic mean for the abovementioned wires was listed in [Table 1] (conventional brackets with unconventional modules), [Table 2] (conventional brackets with conventional modules), and [Table 3] (passive SLBs). The three groups were also compared for homogeneity of means. Another variable to be compared with other means is Kmax. During the traction test of each group and subgroup, maximum force is utilized during kinetic movement in few places. That reading is taken as kinetic maximum (Kmax). The variables in each group were subjected to one-way analysis of variance.
Table 1: Statistical analysis for Group I - conventional brackets with unconventional modules

Click here to view
Table 2: Statistical analysis for Group II - conventional brackets with conventional modules

Click here to view
Table 3: Statistical analysis for Group III - self-ligating brackets

Click here to view


The mean frictional values for each group are represented in [Graph 1], [Graph 2], [Graph 3]. On comparing, conventional brackets with conventional modules showed a higher mean than the other two. SLBs had a mean little greater conventional bracket with unconventional module.



The static friction mean of conventional brackets with unconventional modules is 0.1836, and for conventional brackets with conventional module is 0.5450, 0.1422 for SLBs. On comparing, conventional brackets with conventional module showed a higher static mean than the other two. SLBs showed a static mean little lower than conventional bracket with unconventional module.

The kinetic friction mean of conventional brackets with unconventional module is 0.2519, and for conventional brackets with conventional module is 0.9848, 0.4761 for SLBs. On comparison, conventional brackets with conventional module showed a higher kinetic mean than the other two. SLBs had kinetic mean little greater than conventional bracket with unconventional module.

The Kmax mean of conventional brackets with unconventional module is 1.2368, for conventional brackets with conventional module is 2.1486, and for SLB is 1.4044. On comparison, conventional brackets with conventional module showed a higher kinetic mean than the other two. SLBs had kinetic mean little greater than conventional brackets with unconventional modules.

Descriptive statistics and statistical comparisons of the frictional forces recorded in the different bracket/wire/ligation combinations are reported in [Table 4]. [Table 4] shows the statistical comparison among the three groups: (i) conventional brackets with unconventional modules were compared with conventional brackets with conventional modules, (ii) conventional brackets with unconventional module were compared with passive SLBs, and (iii) conventional brackets with conventional modules were compared with passive SLBs. Asterisk is indicated as significant. (i) and (iii) showed a statistically significant difference in values, whereas (ii) was statistically nonsignificant.
Table 4: Statistical comparison for all groups

Click here to view



   Discussion Top


Most investigations[4],[5],[6] have concluded that elastomeric modules significantly increase resistance to sliding compared with SS ligatures, especially when the SS ligatures are tied loosely. Thus, SLBs[7],[8],[9],[10] were considered to reduce friction. When the UELs are tied to conventional brackets, the ligature is completely passive. Previous in vitro studies[11],[12] showed that the UELs can reduce friction compared to CELs during leveling and aligning orthodontic tooth movement.

The results of the present study indicate that both SLB and UEL on CB produced significantly lower frictional forces compared with CEL on CB when coupled with 0.014” NiTi wire, 0.016” NiTi wire, 0.017” × 0.025” SS wire, and 0.019” × 0.025” SS wire. These results are in agreement with those that of previous studies[13],[14] which found that passive SLBs generated less frictional forces than conventional ligatures on CBs. The differences between SLB and CEL on CB are significant in the current study and are very similar to those reported by Paolo Gandini et al.[15] and Thomas et al.[16]

A previous in vitro study[13] by Lorenzo Franchi and Tiziano Bacetti compared the frictional forces generated by UELs and CELs during leveling and aligning phases with 0.014” superelastic NiTi wire and 0.019” × 0.025” SS wire. The results indicated that, when a slight amount of tooth alignment is needed (1.5 mm), the differences in the performance of UEL and CEL were minimal, but these differences become extremely significant when correction of misalignment of more than 3 mm is attempted. A null amount of force for alignment was produced by CEL, thus they came to a conclusion that the amount of force generated with UEL during the aligning phase of orthodontic tooth movement was significantly greater than that produced with CEL.

The results of the present study corroborate the results of the previous studies by Paolo Gandini[15] et al. and Baccetti et al.[11] who reported significantly lower frictional values for CB with UEL compared with CB with CEL.

Based on the result, it is concluded that UELs are able to produce significantly lower levels of frictional forces than CEL when applied on conventional brackets, and they produce less friction almost similar to SLBs. Thus, UEL may represent a valid alternative to passive SLBs for low frictionless mechanics.

The clinical interpretation of these experimental data, however, requires further considerations that modulate the findings. Minimal adjustments at the bracket/wire/ligature system may significantly change frictional resistance because of physiologic oral functions as well as the oral tissues or food contacting the orthodontic appliance.


   Conclusion Top


  • UELs on conventional brackets and SLBs are able to produce lower frictional force when compared with CELs on conventional brackets when coupled with 0.014”, 0.016” NiTi wire and 0.017” × 0.025”, 0.019” × 0.025” SS wire
  • UELs may represent a valid alternative to passive SLBs for low friction biomechanics
  • Friction and low-friction mechanics can be applied simultaneously on the same archwire by using CELs and UELs only in particular segments, i.e., UELs can be used in the posterior segments to reduce friction, whereas CELs are used in the anterior segment.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Vaughan JL, Duncanson MG Jr., Nanda RS, Currier GF. Relative kinetic frictional forces between sintered stainless steel brackets and orthodontic wires. Am J Orthod Dentofacial Orthop 1995;107:20-7.  Back to cited text no. 1
    
2.
Damon DH. The rationale, evolution and clinical application of the self-ligating bracket. Clin Orthod Res 1998;1:52-61.  Back to cited text no. 2
    
3.
Taylor NG, Ison K. Frictional resistance berween orthodontic brackets and the archwire and buccal segments. Angle Orthod 1996;66:215-22.  Back to cited text no. 3
    
4.
Gandini P, Orsi L, Bertoncini C, Massironi S, Franchi L. In vitro frictional forces generated by three different ligation methods. Angle Orthod 2008;78:917-21.  Back to cited text no. 4
    
5.
Hain M, Dhopatkar A, Rock P. The effect of ligation method on friction in sliding mechanics. Am J Orthod Dentofacial Orthop 2003;123:416-22.  Back to cited text no. 5
    
6.
Thorstenson G, Kusy R. Influence of stainless steel inserts on the resistance to sliding of aesthetic brackets with Second Order Angulation in the dry and wet states. Angle Orthod 2003;73:167-75.  Back to cited text no. 6
    
7.
Thorstenson GA, Kusy RP. This study was done to evaluate the effect of ligation type and method on the resistance to sliding of orthodontic brackets with second order angulation in dry and wet states. Angle Orthod 2003;73:418-30.  Back to cited text no. 7
    
8.
Pizzoni L, Ravnholt G, Melsen B. Investigation of friction induced by self-ligating brackets on stainless steel and beta titanium wires, both in round and rectangular cross-sections. Euro J Orthod 1998;20:283-91.  Back to cited text no. 8
    
9.
Thorstenson GA, Kusy.RP. This study was done to compare the resistance to sliding between different self-ligating brackets with second order angulations in the dry and wet states. Am J Orthod 2002;121:472-82.  Back to cited text no. 9
    
10.
Chimenti C, Franchi L, Di Giuseppe MG, Lucci M. Friction of orthodontic elastomeric ligatures with different dimensions. Angle Orthod 2005;75:421-5.  Back to cited text no. 10
    
11.
Tecco S, Festa F, Caputi S, Traini T, Di Iorio D, D'Attilio M. Friction of conventional and self-ligating brackets using a 10 bracket model. Angle Orthod 2005;75:1041-5.  Back to cited text no. 11
    
12.
Baccetti T, Franchi L. Comparison of frictional forces generated by New nonconventional passive elastomeric ligatures and conventional elastomeric ligatures under dry conditions. Angle Orthod 2006;76:211-6.  Back to cited text no. 12
    
13.
Franchi L, Baccetti T. Forces released during alignment with a Pre-adjusted appliance with different types of elastomeric ligatures. Am J Orthod 2006;129:687-90.  Back to cited text no. 13
    
14.
Thorstenson GA, Kusy RP. Resistance to sliding of self ligating brackets versus conventional stainless steel twin brackets with second order angulation in dry and wet states. Am J Orthod 2001;120:361-70.  Back to cited text no. 14
    
15.
Griffiths HS, Sherriff M, Ireland AJ. Resistance to sliding of three types of elastomeric modules. Am J Orthod 2005;127:670-5.  Back to cited text no. 15
    
16.
Thomas S, Sherriff M, Birnie D. A comparative in vitro study of the frictional characteristics of two types of self-ligating brackets and two types of pre-adjusted edgewise brackets tied with elastomeric ligatures. Eur J Orthod 1998;20:589-96.  Back to cited text no. 16
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
   Introduction
   Materials
   Methods
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed302    
    Printed6    
    Emailed0    
    PDF Downloaded43    
    Comments [Add]    

Recommend this journal