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Table of Contents
ORIGINAL ARTICLE
Year : 2021  |  Volume : 9  |  Issue : 1  |  Page : 5-7

Evaluation of friction of stainless steel wires after clinical use


1 Department of Periodontics, Ahmedabad Dental College and Hospital, Bhadaj, Gujarat, India
2 Department of Oral and Maxillofacial Surgery, Siddhpur Dental College and Hospital, Siddhpur, Dist Patan, Gujarat, India
3 Department of Oral Medicine and Radiology, Siddhpur Dental College and Hospital, Siddhpur, Dist Patan, Gujarat, India
4 Department of Prosthodontics, RUHS College of Dental Sciences, Jaipur, Rajasthan, India
5 Department of Orthodontics and Dentofacial Orthopedics, Siddhpur Dental College and Hospital, Siddhpur, Dist Patan, Gujarat, India
6 Department of Public Health Dentistry, Siddhpur Dental College and Hospital, Siddhpur, Dist Patan, Gujarat, India

Date of Submission30-Oct-2020
Date of Acceptance22-Nov-2020
Date of Web Publication18-Feb-2021

Correspondence Address:
Dr. Sapna Pritesh Ganna
Department of Periodontics, Ahmedabad Dental College and Hospital, A-1/809, Anand Laxmi Apartment Near Railway Crossing, Behind Shanidev Temple, Shahibaug, Ahmedabad, Gujarat.
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/INJO.INJO_45_20

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  Abstract 

Aims: To investigate the changes that occur in stainless steel (SS) orthodontic arch wires before and just after clinical use for eight weeks. To evaluate changes in the wire surface roughness, and the friction produced during sliding. Materials and Methods: Eight candidates were selected for this study. The 0.022″ × 0.028″ MBT first premolar brackets were bonded on the first premolar, second premolar, and first molar of the maxillary arch on both the sides, and straight, passive 0.019″ × 0.025″ SS wire was ligated with elastic modules. After eight weeks, the wires were removed and friction and roughness were evaluated. Results: Results showed a significant increase in the surface roughness from 0.644 Ra to 2.018 Ra after clinical use; friction of the wire too increased from 0.7N to 2.52N after clinical use. P values for both were <0.0001, which showed that the changes were very highly significant. Conclusion: The results concluded that the increase in the friction and roughness values would affect the sliding of the wire and increase the treatment duration.

Keywords: Friction, roughness, stainless steel


How to cite this article:
Ganna SP, Patel CN, Shah DS, Kalla R, Ganna PS, Chaudhary NJ. Evaluation of friction of stainless steel wires after clinical use. Int J Oral Care Res 2021;9:5-7

How to cite this URL:
Ganna SP, Patel CN, Shah DS, Kalla R, Ganna PS, Chaudhary NJ. Evaluation of friction of stainless steel wires after clinical use. Int J Oral Care Res [serial online] 2021 [cited 2021 Apr 13];9:5-7. Available from: https://www.ijocr.org/text.asp?2021/9/1/5/309664




  Introduction Top


Friction is a function of the relative roughness of two surfaces in contact, and it arises when there is relative motion or potential for it between the two surfaces.[1]

High levels of bracket wire friction may result in binding of the bracket accompanied by little or no tooth movement. The ideal situation is one in which no friction exists between bracket and wire. Since this does not occur, knowledge of the magnitude of friction will help the orthodontist to achieve the optimal force.

Studies examining wires as received from the manufacturer have shown an inverse relationship between the force loss caused by friction, the slot size, and the interbracket distance.[2],[3] Direct relationships between the frictional force and the wire section diameter,[3] as well as the angulation between the bracket and the wire,[4] have been reported. Despite some inconsistency in the literature, studies have demonstrated that SS wires produce less friction than other materials.[5],[6],[7] Authors such as Tecco et al. and Thorstensen compared the resistance with the sliding of self-ligating brackets and conventional brackets, wherein the results showed that the friction was almost similar with no statistically significant difference.[8]

Friction between the bracket and arch wire can cause up to 50% loss of force.[1],[5] Numerous factors have an impact on friction and it is very difficult to isolate individual factors. Studies have shown that the surface characteristics influence both the friction and the biocompatibility of orthodontic arch wires in situ.[9],[10],[11]

The aim of this study was to investigate the changes that occur in SS orthodontic arch wires before and just after clinical use for eight weeks. Changes in the wire surface roughness, and the friction produced during sliding were evaluated both before and after exposure to the oral environment.


  Materials and Methods Top


For this study, eight individuals (five male and three female) were selected. Overall, 16 wire segments 0.019 × 0.025 inch SS arch wires (Rabbit force, libral traders) were used by cutting 8-as received arch wires. The effects of intraoral exposure were examined in eight adult individuals, who received a bonding consisting of a set of three MBT upper first premolar brackets of the corresponding side, slot 0.022″ × 0.028″ (Centrino, Libral Traders – 0.022″ slot) in each hemiarch (n = 16), from the first molar to the first premolar. A straight segment of the same SS wire (0.019″ × 0.025″) was inserted into each of the 16 sets of brackets [Figure 1] and [Figure 2]. The wire bracket assembly was kept for a period of eight weeks.
Figure 1: Front view of the intraoral picture of bonded brackets with 19X25 stainless steel wire

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Figure 2: Side view of the intraoral picture of bonded brackets with 19X25 stainless steel wire

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The wires were then removed after eight weeks. Surface roughness of the wire was examined with a rugosimeter (Mitutoyo Sj 301). Surface roughness of the as-received wire at both T0 and after eight weeks of intraoral exposure T1 was examined.

Friction testing was done on a universal testing machine. Kinetic frictional force was measured in Newtons, using the force exerted from the beginning of the movement until the end of the test. Here also, frictional force of the as-received wire at both T0 and after eight weeks of intraoral exposure T1 was examined.

Statistical Analysis

A paired t test for friction and surface roughness of wires both before and after clinical use was done. Spearman correlation analysis for the association between kinetic friction and roughness was done.


  Results Top


Before exposure to the oral environment (T0), the wires showed homogeneity (SD 0.644) and very low values of roughness, with an average Ra of 2.018. Eight weeks of intraoral exposure (T1) caused a significant increase in the degree of roughness of the wires (P < 0.001). The segments of the wire at T1 showed a mean value of Ra = 4.336 (SD = 0.27). The paired-sample t test, P < 0.001, was very highly significant.

There was a significant increase in frictional force from T0 to T1 (P < 0.001), with an average increase of 1.8N from 00.018N to 0.135N. The paired-sample t test, P < 0.001, was very highly significant.

Descriptive statistics show that the mean value for roughness was 2.35 (minimum –1.6 and maximum –3.84) with a standard deviation of 0.727. Moreover, the mean for friction was 1.82 (minimum –3.3 and maximum –0.6) with a standard deviation of 0.542.

Correlation [Table 1] between frictional force and surface roughness in Spearman’s correlation analysis showed no association between kinetic friction and roughness (r = –0.323, P = 0.223). As the P value was >0.5, the correlation between friction and roughness was not significant.
Table 1: Correlation

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  Discussion Top


There have been a few studies on NiTi arch wires wherein the effects of time on arch wire roughness, surface topography, fracture, and friction were studied.[12],[13],[14]

The SS wire has been evaluated recently in one study,[2] which showed that SS rectangular wires, when exposed to the intraoral environment for eight weeks, showed a significant increase in the degree of debris and surface roughness, causing an increase in friction between the wire and bracket during the mechanics of sliding.

In another investigation,[15] the NiTi arch wires showed higher coefficients of friction and roughness after four weeks of clinical use. The MBT bracket system was used in the current study, because this is one of the most commonly used bracket systems. The choice of elastic ligatures was made, because they are the first choice for most clinical orthodontists. Furthermore, it is more difficult to standardize the tying strength when using SS ligatures.

The current study showed an increase in the friction values from 0.7N to 2.52N. Roughness values also showed a significant increase (T0 = 2.018 and T1 = 4.366). There was no significant correlation between the increase in the friction and roughness values. No correlation in this study might be attributed to the bracket angulation of MBT brackets. Further investigations are still required with a greater number of samples, and also frequent cleaning of the wire at regular intervals for an increased period.

The values previously reported seem to differ from those of the current study. The reasons can be

  • - Material used: NiTi or SS


  • - Bracket angulation: edgewise and MBT


  • - Difference in elastic module, bracket material, and arch wire manufacturing



  Conclusion Top


In this study, it was concluded that the SS rectangular wires (0.019″ × 0.025″), which usually stay for a longer period, around three to eight months or more, during retraction showed a significant increase in the values of friction and roughness when exposed to the intraoral environment for eight weeks. This increase in the friction and roughness values can increase the total duration of treatment time, and hence it is significant.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/ have given his/ her/ their consent for his/ her/ their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Burstone CJ, Farzin-Nia F Production of low-friction and colored TMA by ion implantation. J Clin Orthod 1995;29:453-61.  Back to cited text no. 1
    
2.
Marquesa ISV, Joa AMA, Gurgel JLA, Normandoc D Debris, roughness and friction of stainless steel archwires following clinical use. Angle Orthod 2010;80:521-7.  Back to cited text no. 2
    
3.
Kapila S, Angolkar PV, Duncanson MG Jr, Nanda RS Evaluation of friction between edgewise stainless steel brackets and orthodontic wires of four alloys. Am J Orthod Dentofacial Orthop 1990;98:117-26.  Back to cited text no. 3
    
4.
Frank CA, Nikolai RJ A comparative study of frictional resistances between orthodontic bracket and arch wire. Am J Orthod 1980;78:593-609.  Back to cited text no. 4
    
5.
Drescher D, Bourrauel C, Schumacher HA Friction forces between bracket and arch wire. Am J Orthod Dentofac Orthop 1989;96:397-404.  Back to cited text no. 5
    
6.
Kusy RP, Whitley JQ Coefficients of friction for arch wires in stainless steel and polycrystalline alumina bracket slots. I. The dry state. Am J Orthod Dentofacial Orthop 1990;98:300-12.  Back to cited text no. 6
    
7.
Mendes K, Rossouw PE Friction: Validation of manufacturer’s claim. Semin Orthod 2003;9:236-50.  Back to cited text no. 7
    
8.
Thorstenson GA, Kusy RP Resistance to sliding of self-ligating brackets versus conventional stainless steel twin brackets with second-order angulation in the dry and wet (saliva) states. Am J Orthod Dentofacial Orthop 2001;120:361-70.  Back to cited text no. 8
    
9.
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 Orthop1995; 107:20-7.  Back to cited text no. 9
    
10.
Berger JL The influence of the SPEED bracket’s self-ligating design on force levels in the tooth movement: A comparative in vitro study. Am J Orthod Dentofac Orthop 1990;97:219-28.  Back to cited text no. 10
    
11.
Bourauel C, Fries T, Drescher D, Plietsch R Surface roughness of orthodontic wires via atomic force microscopy, laser specular reflectance, and profilometry. Eur J Orthod 1998;20:79-92.  Back to cited text no. 11
    
12.
Burrow SJ Friction and resistance to sliding in orthodontics: A critical review. Am J Orthod Dentofacial Orthop 2009;135: 442-7.  Back to cited text no. 12
    
13.
Iwasaki LR, Beatty MW, Randall CJ, Nickel JC Clinical ligation forces and intraoral friction during sliding on a stainless steel archwire. Am J Orthod Dentofacial Orthop 2003;123:408-15.  Back to cited text no. 13
    
14.
Van Eldik DA, Zilm PS, Rogers AH, Marin PD A SEM evaluation of debris removal from endodontic files after cleaning and steam sterilization procedures. Aust Dent J 2004;49:128-35.  Back to cited text no. 14
    
15.
Wichelhaus A, Geserick M, Hibst R, Sander FG The effect of surface treatment and clinical use on friction in niti orthodontic wires. Dent Mater 2005;21:938-45.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1]



 

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