Effect of ion‑implantation on surface characteristics of nickel titanium ...

[Downloaded free from http://www.ijdr.in on Tuesday, October 01, 2013, IP: 125.16.60.178] || Click here to download free Android application for this journal 

Original Research 

<strong>Effect</strong> <strong>of</strong> ion-implantation on surface characteristics <strong>of</strong> nickel 

titanium and titanium molybdenum alloy arch wires 

Manu Krishnan, Seema Saraswathy 1 , Kalathil Sukumaran 2 , Kurian Mathew Abraham 3 

Department <strong>of</strong> Dental Research 

and Implantology, Institute <strong>of</strong> 

Nuclear Medicine and Allied 

Sciences (INMAS), Defence 

Research and Development 

Organization (DRDO), Ministry 

<strong>of</strong> Defence, Govt <strong>of</strong> India, 

Timarpur, Delhi, 1 School <strong>of</strong> 

Medicine and Paramedical 

Health Sciences, Indraprastha 

University, Delhi, 2 Materials 

and Minerals Division, National 

Institute for Interdisciplinary 

Science and Technology, 

Council <strong>of</strong> Scientific and 

Industrial Research, Industrial 

Estate, Thiruvananthapuram, 

3 

Department <strong>of</strong> Biostatistics, 

Mar Thoma College, Mahatma 

Gandhi University, Thiruvalla, 

Kerala, India 

Received : 11-10-12 

Review completed : 07-02-13 

Accepted : 05-03-13 

ABSTRACT 

Aim: To evaluate the changes in surface roughness and frictional features <strong>of</strong> ‘ion-implanted 

nickel titanium (NiTi) and titanium molybdenum alloy (TMA) arch wires’ from its conventional 

types in an in-vitro laboratory set up. 

Materials and Methods: ‘Ion-implanted NiTi and low friction TMA arch wires’ were assessed 

for surface roughness with scanning electron microscopy (SEM) and 3 dimensional (3D) optical 

pr<strong>of</strong>ilometry. Frictional forces were studied in a universal testing machine. Surface roughness 

<strong>of</strong> arch wires were determined as Root Mean Square (RMS) values in nanometers and Frictional 

Forces (FF) in grams. 

Statistical Analysis Used: Mean values <strong>of</strong> RMS and FF were compared by Student’s ‘t’ test and 

one way analysis <strong>of</strong> variance (ANOVA). 

Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical 

pr<strong>of</strong>ilometry demonstrated reduction <strong>of</strong> RMS values by 58.43% for ion-implanted NiTi (795.95 

to 330.87 nm) and 48.90% for TMA groups (463.28 to 236.35 nm) from controls. Nonetheless, 

the corresponding decrease in FF was only 29.18% for NiTi and 22.04% for TMA, suggesting 

partial correction <strong>of</strong> surface roughness and disproportionate reduction in frictional forces with 

ion-implantation. Though the reductions were highly significant at P < 0.001, relations between 

surface roughness and frictional forces remained non conclusive even after ion-implantation. 

Conclusion: The study proved that ion-implantation can significantly reduce the surface 

roughness <strong>of</strong> NiTi and TMA wires but could not make a similar reduction in frictional forces. 

This can be attributed to the inherent differences in stiffness and surface reactivity <strong>of</strong> NiTi 

and TMA wires when used in combination with stainless steel brackets, which needs further 

investigations. 

Key words: Frictional forces, optical pr<strong>of</strong>ilometry, root mean square roughness 

INTRODUCTION 

Surface topographic features <strong>of</strong> orthodontic arch wires 

crucially influence its clinical and biologic behavior. 

Presently four types <strong>of</strong> arch wire alloys are used in 

orthodontics: Stainless steel (SS), cobalt chromium (Co-Cr), 

nickel titanium (NiTi), and titanium molybdenum alloy/ 

beta titanium (TMA). Surface roughness <strong>of</strong> these arch wires 

using laser spectroscopy and specular reflectance were first 

Address for correspondence: 

Lt Col (Dr) Manu Krishnan 

E mail: manukrishnanin@yahoo.co.in 

411 

Quick Response Code: 

Access this article online 

Website: 

www.ijdr.in 

PMID: 

*** 

DOI: 

10.4103/0970-9290.118375 

reported by Kusy et al., [1] in 1988 and was followed by several 

other experiments; [2-8] findings <strong>of</strong> which can be summarized 

as; surface roughness increases in the following order: SS 

< Co-Cr < TMA < NiTi. The parameters, which are related 

to surface roughness <strong>of</strong> orthodontic arch wires, include; 

esthetics, frictional forces at arch wire bracket interface, 

adhesion <strong>of</strong> bio-film and propensity for intra-oral corrosion. 

Since frictional forces are generated between arch wire and 

bracket slot at all stages <strong>of</strong> treatment starting from initial 

leveling and alignment through space closure to finishing, 

and exert significant influences in the biologic mechanisms 

<strong>of</strong> tooth movement, substantial focus has been put to this 

aspect. 

The high frictional force associated with titanium 

molybdenum alloy and NiTi arch wires have prompted 

many researchers to investigate whether this is related to 

its high surface roughness, but no definitive association 

between the two could be derived hitherto and the current 

understanding is that frictional forces <strong>of</strong> orthodontic arch 

wires increase in the order: SS < Co-Cr < NiTi < TMA. 

Indian Journal <strong>of</strong> Dental Research, 24(4), 2013


Surface characterization <strong>of</strong> low friction arch wires 

[2,9,10] 

A direct relationship between surface roughness 

and frictional forces holds good only for stainless steel 

and Co-Cr wires but not for NiTi and TMA. It, therefore, 

appears paradoxical that NiTi with an inherent high 

surface roughness produces less friction than TMA with 

a smoother exterior. 

NiTi and TMA wires have important roles in contemporary 

pre-adjusted orthodontic mechanotherapy. NiTi alloy 

possess unique properties like shape memory, superelasticity, 

large spring back and low stiffness which make 

them suitable for initial stages <strong>of</strong> treatment. [11] On the other 

hand, TMA wires with a modulus <strong>of</strong> elasticity approximately 

twice that <strong>of</strong> NiTi and less than half <strong>of</strong> SS, display adequate 

spring back, and ability to impart light continuous forces 

over long duration. With its added formability and 

weldability features, it is useful in the intermediate stages 

<strong>of</strong> treatment. [12] Many studies have pointed to the high 

frictional forces associated with NiTi and TMA arch wires 

compared to SS and Co-Cr. [9,13] 

It is in this context that ion-implanted/surface modified 

TMA and NiTi wires are introduced by quite a few 

manufacturers. TMA wires with ion-implantation have 

shown to reduce friction to some extent with varying 

claims, [14,15] whereas evidences lack for surface-modified 

NiTi wires. Ion-implantation involves physical vapor 

deposition <strong>of</strong> desirable elements on a substrate from a 

plasma state at energies ranging from 100-1000 electron 

volts and temperatures up to 700°C, mediated under 

vacuum conditions. [16] The deposited material form 

compounds with the base material and creates a hard 

surface with high compressive forces. It thus rectifies the 

surface defects <strong>of</strong> substrate; improve its fatigue resistance, 

ductility and coefficient <strong>of</strong> friction. With advancements 

in surface metrology, non-invasive/destructive optical 

methods like ellipsometry, interferometry, atomic force 

microscopy, and optical pr<strong>of</strong>ilometry are available for 

studying surface roughness <strong>of</strong> orthodontic arch wires. [4] 

Optical pr<strong>of</strong>iling <strong>of</strong>fers versatility due to the ease in 

handling samples and in its ability to scan a wide area in 

short time. In this method, white light is passed through 

a beam filter, which directs the light to the sample surface 

and a reference mirror. When the light reflected from 

two surfaces recombine, a pattern <strong>of</strong> interference ‘fringes’ 

emerge from the sample surface that helps in deducing 

surface roughness to a resolution <strong>of</strong> 0.1 nm. [17] 

With the launch <strong>of</strong> surface modified NiTi and TMA wires, 

it is therefore prudent to find out the relationship between 

surface roughness and frictional forces for such products and 

to evaluate its clinical utility. Therefore, aim <strong>of</strong> this study 

was to determine the surface roughness <strong>of</strong> ion-implanted 

NiTi and TMA wires with its conventional counterparts 

using scanning electron microscopy and optical pr<strong>of</strong>ilometry 

and the corresponding frictional forces in an in-vitro set up. 

Indian Journal <strong>of</strong> Dental Research, 24(4), 2013 

MATERIALS AND METHODS 

Krishnan, et al. 

Following arch wires were selected for the study: Bi<strong>of</strong>orce 

Sentalloy Ionguard Nickel Titanium; Ion-implanted NiTi <strong>of</strong> 

0.018 × 0.025 inches (0.457 × 0.635 mm) GAC International, 

Inc; Central Islip, NY, and Low friction, Ion-implanted beta 

titanium, TMA arch wire <strong>of</strong> 0.017 × 0.025 inches (0.431 × 

0.635 mm), Ormco Corp, South Lone Hill Avenue, Glendora, 

CA. Respective dimensions <strong>of</strong> conventional NiTi and TMA 

(C-NiTi and C-TMA) arch wires without ion-implantation 

from the same manufacturers were used as controls [Table 1]. 

Surface features <strong>of</strong> arch wires were initially assessed with 

surface electron micrographs at 500X magnification; Hitachi 

scanning electron microscope, S-2400, Hitachi Instruments, 

Inc, San Jose, CA. Wyko NT 1100 series optical pr<strong>of</strong>ilometer; 

Veeco instruments, Inc, Woodbury NY, USA, was used 

for assessing the surface roughness <strong>of</strong> arch wires. The x, 

y, range <strong>of</strong> the contour map was determined by the size 

<strong>of</strong> the microscope objective and the z range or height was 

determined by the mechanical movement <strong>of</strong> the sample stage. 

Ten different regions in a 0.5 mm × 0.05 mm area <strong>of</strong> arch wire 

surface was scanned to study its topography and averages 

were taken. The ‘Wyko vision s<strong>of</strong>tware’ <strong>of</strong> the equipment 

was used for data processing to represent surface roughness 

as Root Mean Square Roughness (RMS) value in nanometers. 

Frictional testing was done as per an in-vitro test protocol 

described by Tidy. [18] Frictional forces were measured in 

grams (g) using a universal testing machine (Autograph AG 

2000G, Schimadzu, Kyoto, Japan). Ten arch wire samples 

from each group were pulled for a distance <strong>of</strong> 16mm at a 

crosshead speed <strong>of</strong> load cell at 5 mm/minute. A conventional 

stainless steel pre-adjusted bracket; 0.022 inch slot 

(0.558 mm) and an elastomeric module (Gemini series, 3M 

Unitek Monrovia, CA) was used for friction testing to ensure 

uniformity among all groups. Study was done under dry 

conditions and with proprietary s<strong>of</strong>t ware <strong>of</strong> the machine, 

kinetic frictional force was determined. 

Student’s ‘t’ test was used for statistical comparisons <strong>of</strong> mean 

surface roughness values and frictional forces. Analysis <strong>of</strong> 

variance (one-way ANOVA) was done to compare all tested 

Table 1: Study design (n = 10) 

Group 

and code 

Conventional 

NiTi (C-NiTi) 

Ion guard 

NiTi (I-NiTi) 

Conventional 

TMA (C-TMA) 

Ion-implanted 

TMA (I-TMA) 

Manufacturer Product Arch wire 

dimension in mm 

GAC 

GAC 

Ormco 

Ormco 

Nickel 

titanium 

Nickel 

titanium 

Titanium 

molybdenum 

alloy 

Titanium 

molybdenum 

alloy 

0.457 × 0.635 

0.457 × 0.635 

0.431 × 0.635 

0.431 × 0.635 

412




groups together. A probability value, P < 0.05 was considered 

as significant. 

RESULTS 

Figures 1-4 shows the SEM images <strong>of</strong> conventional and 

ion-implanted NiTi and TMA wires. Ion-implanted 

groups demonstrated a smooth surface texture compared 

to controls. Surface topographic and 3D pr<strong>of</strong>ilometric 

images [Figures 5-12] showed raised and irregular peaks in 

conventional where as ion-implanted types exhibited more 

or less even peaks. 

RMS values in nanometers and frictional force in gram <strong>of</strong> 

conventional and ion-implanted NiTi and TMA arch wires 

are depicted in Table 2. Surface roughness <strong>of</strong> conventional 

NiTi wire was 795.95 nm and that <strong>of</strong> TMA was 463.28 nm. 

Ion-implanted NiTi and TMA registered roughness values 

<strong>of</strong> 330.87 nm and 236.35 nm respectively. Statistical analysis 

between conventional and ion-implanted groups recorded 

highly significant (P < 0.001) differences. The surface 

roughness <strong>of</strong> ion-implanted NiTi and TMA was reduced 

by 58.43% and 48.90%, respectively, from control groups 

[Figure 13]. Similarly, mean frictional forces (gm) also 

showed significant (P < 0.001) differences among study 

groups. Mean frictional force <strong>of</strong> conventional NiTi and 

TMA were 68.36 gm and 99.81 gm, both <strong>of</strong> which were 

found reduced to 48.41 gm (29.18%) and 77.81 gm (22.04%), 

respectively, for ion-implanted groups [Figure 13]. 

DISCUSSION 

The effects <strong>of</strong> bracket-arch wire material, nature <strong>of</strong> their 

surfaces: Smooth/rough, size, shape, angulations, ligation 

modes, and interactions with saliva on orthodontic 

frictional forces have been well documented. [9,13] This is 

clinically important because frictional forces can influence 

the effectiveness <strong>of</strong> orthodontic materials in delivering 

light continuous forces; that are so essential for eliciting an 

optimum biologic response. [19] Classically, friction between 

two surfaces is directly related to the features <strong>of</strong> opposing 

surfaces; like surface roughness. [20,21] Indeed, it is determined 

Figure 1: Scanning electron micrograph <strong>of</strong> conventional NiTi wire at 

500X 

Figure 2: Scanning electron micrograph <strong>of</strong> ion-implanted NiTi wire 

at 500X 

Figure 3: Scanning electron micrograph <strong>of</strong> conventional TMA wire 

at 500X 

413 

Figure 4: Scanning electron micrograph <strong>of</strong> low friction TMA wire at 

500X 





Figure 5: Optical pr<strong>of</strong>ilograph <strong>of</strong> conventional NiTi wire 

Figure 6: 3D optical pr<strong>of</strong>ilograph <strong>of</strong> conventional NiTi wire 

Figure 7: Optical pr<strong>of</strong>ilograph <strong>of</strong> ion-implanted NiTi wire 

Figure 8: 3D optical pr<strong>of</strong>ilograph <strong>of</strong> ion-implanted NiTi wire 

Figure 9: Optical pr<strong>of</strong>ilograph <strong>of</strong> conventional TMA wire 

by the peaks <strong>of</strong> surface irregularities termed as ‘asperities’ 

and to its deformation occurring under impact <strong>of</strong> applied 

load. So there is a continuous binding/notching and release 

or ‘stick-slip’ phenomenon between arch wire, bracket slot 

and ligature interface [19] which makes it a complex entity, 

difficult to be explained by the laws <strong>of</strong> friction. [9,18] 


Figure 10: 3D optical pr<strong>of</strong>ilograph <strong>of</strong> conventional TMA wire 

Beta titanium or TMA alloy has a composition <strong>of</strong> titanium 

(79%), molybdenum (11%), zirconium (6%), and tin (4%). [21] 

The high content <strong>of</strong> Ti (79%) in TMA wires compared 

to NiTi (45-50%) increases its surface reactivity and has 

been attributed to its increased adhesion to bracket slot 

causing higher frictional forces. [19] The same is said to 

414




Figure 11: Optical pr<strong>of</strong>ilograph <strong>of</strong> low friction TMA wire 

Figure 12: 3D optical pr<strong>of</strong>ilograph <strong>of</strong> low friction TMA wire 

Table 2: Comparison <strong>of</strong> root mean surface roughness 

(RMS) values in nm and frictional forces (FF) in g between 

conventional and ion-implanted arch wires 

Parameter Group Mean ± SD t value P value 

RMS (nm) C-NiTi 795.95 11.74 81.424




<strong>of</strong> 0.154 µm. The high roughness <strong>of</strong> NiTi surface was in 

accordance with our findings. However, it is known that laser 

spectroscopy measurements involve extensive mathematical 

calculations but optical pr<strong>of</strong>ilometry measurements are easy 

with modern computer algorithms. Laser spectroscopy also 

restricts analysis <strong>of</strong> data that is presentable only in a Gaussian 

pr<strong>of</strong>ile and RMS values need to be less than the wavelength 

<strong>of</strong> the testing laser. [4] Conversely, optical pr<strong>of</strong>ilometry used 

in this study does not have such limitations and allow easy 

computation <strong>of</strong> RMS value. [17] 

Surface roughness <strong>of</strong> TMA wires was successfully altered 

by Burstone and Farzin-Nia [14] using ion-implantation. 

With ion-implanted TMA wires against stainless steel flats 

at different loads, they observed lower static and kinetic 

coefficient <strong>of</strong> frictions. In fact, they found values as low as 

stainless steel both in the dry and wet conditions. However, 

this sweeping reduction was not seen in the present study 

and can be ascribed to the differences in testing modes used 

by us with stainless steel pre-adjusted brackets. 

Bourauel et al., [4] in a comprehensive review showed RMS 

values <strong>of</strong> 0.21 µm for TMA and 0.10-1.3 µm for NiTi, which 

was less than the present results. They had used methods 

like laser specular reflectance, atomic force microscopy 

(AFM) and pr<strong>of</strong>ilometry for calibrating surface roughness 

and differences were expected as manufacturer variations 

and measuring methods can influence RMS values. AFM and 

specular reflectance use a certain region <strong>of</strong> the wire surface 

while pr<strong>of</strong>ilometry uses a single line to determine the surface 

properties which is time consuming and difficult for samples 

like orthodontic wire. It also can damage the scanned surface 

and <strong>of</strong>ten mislead interpretation. [4] Optical pr<strong>of</strong>iling or white 

light interferometry on the other hand ensures no damage 

to samples and facilitates accurate understanding. [17] 

In a major investigation involving TMA wires with laser 

specular reflectance, Kusy and co-workers [6] could not find any 

difference in surface roughness between colored-low friction 

and normal TMA wires. They found almost similar surface 

roughness (0.195 µm) for conventional and low friction 

types. The frictional coefficients also showed negligible 

relationship with its surface roughness. Cash et al., [15] 

too noticed no advantages for low friction, colored TMA 

over conventional but ion-implanted types showed a 

reduction in frictional forces which were in par with the 

present findings. There was a discernible reduction (RMS 

value: 0.463-0.236 µm) in this study for TMA groups that 

did not transform to an analogous reduction in frictional 

forces. Doshi and Bhad-Patil, [8] however, reported reduced 

RMS and frictional values for low friction TMA with ceramic 

brackets but could not establish a direct correlation between 

two factors which was true for the present study also. 

Considering the different methods used for surface 

roughness estimation and wide variation in data available 


with the literature, it would be better not to take these 

values on a universal scale for comparison. This can be 

probably due to the differences in the types <strong>of</strong> samples 

and methods followed. Percentage changes in RMS and 

frictional force values may be a better option for judgment, 

until we have uniform means in this aspect. The results 

suggested that the currently marketed ion-implanted arch 

wire products cannot contribute to a total reduction in 

surface roughness. More so, its relationship with frictional 

forces tends to be uncertain, even though differences were 

highly significant. The low stiffness <strong>of</strong> TMA and NiTi wires 

with respect to stainless steel slot bracket slot can cause 

bracket slot binding and possibly influence their frictional 

characteristics. This may lessen the expected advantages 

<strong>of</strong> ion-implantation. 

CONCLUSION 

• Scanning electron microscopic and optical pr<strong>of</strong>ilometric 

views <strong>of</strong> ion-implanted NiTi and TMA wires exhibited 

smoother surfaces than conventional control groups. 

• Ion-implantation reduced the surface roughness <strong>of</strong> 

NiTi and beta titanium wires by 58.43% and 48.90%, 

respectively, which suggested need for improving ionimplantation 

procedures for smoother topography. 

• The resultant reduction in frictional forces was only 

29.18% for NiTi and 22.04% for TMA that showed an 

uncertain relationship between surface roughness and 

frictional forces, even after ion-implantation for the 

two materials. 

• Binding <strong>of</strong> NiTi and TMA wires with stainless steel 

bracket slot due to fundamental differences in stiffness 

and surface reactivity <strong>of</strong> titanium may be the probable 

factors that hamper the advantages <strong>of</strong> ion-implantation 

<strong>of</strong> NiTi and TMA wires in minimizing friction. This 

warrants more investigations. 

REFERENCES 

1. Kusy RP, Whitley JQ, Mayhew MJ, Buckthal JE. Surface roughness <strong>of</strong> 

orthodontic arch wires via laser spectroscopy. Angle Orthod 1988; 

58:33-45. 

2. Porosoki RR, Bagby MD, Erickson LC. Static frictional force and surface 

roughness <strong>of</strong> NiTi arch wires. Am J Orthod Dent<strong>of</strong>acial Orthop 1991; 

100:341-8. 

3. Kusy RP. A review <strong>of</strong> contemporary arch wires: Their properties and 

characteristics. Angle Orthod 1997;67:197-207. 

4. Bourauel C, Fries T, Drescher D, Plietsch R. Surface roughness 

<strong>of</strong> orthodontic wires via atomic force microscopy, laser specular 

reflectance, and pr<strong>of</strong>ilometry. Eur J Orthod 1998;20:79-92. 

5. Watanabe I, Watanabe E. Surface changes induced by fluoride 

prophylactic agents on titanium-based orthodontic wires. Am J Orthod 

Dent<strong>of</strong>acial Orthop 2003;123:653-6. 

6. Kusy RP, Whitley JQ, Gurgel JA. Comparisons <strong>of</strong> surface roughnesses 

and sliding resistances <strong>of</strong> 6 titanium-based or TMA-type arch wires. 

Am J Orthod Dent<strong>of</strong>acial Orthop 2004;126:589-603. 

7. Juvvadi SR, Kailasam V, Padmanabhan S, Chitharanjan AB. Physical, 

mechanical, and flexural properties <strong>of</strong> 3 orthodontic wires: An in-vitro 

study. Am J Orthod Dent<strong>of</strong>acial Orthop 2010;138:623-30. 

8. Doshi UH, Bhad-Patil WA. Static frictional force and surface roughness 

416




<strong>of</strong> various bracket and wire combinations. Am J Orthod Dent<strong>of</strong>acial 

Orthop 2011;139:74-9. 

9. Drescher D, Bourauel C, Schumacher HA. Frictional forces 

between bracket and arch wire. Am J Orthod Dent<strong>of</strong>acial Orthop 

1989;96:397-404. 

10. Kusy RP, Whitley JQ. <strong>Effect</strong>s <strong>of</strong> surface roughness on the coefficients 

<strong>of</strong> friction in model orthodontic systems. J Biomech 1990;23:913-25. 

11. Andreasen GF, Heilman H, Krell D. Stiffness changes in thermodynamic 

nitinol with increasing temperature. Angle Orthod 1985;55:120-6. 

12. Burstone CJ, Goldberg AJ. Beta titanium: A new orthodontic alloy. Am 

J Orthod 1980;77:121-32. 

13. Kapila S, Angolkar PV, Duncanson M, Nanda RS. Evaluation <strong>of</strong> friction 

between edgewise stainless steel brackets and orthodontic wires <strong>of</strong> 

four alloys. Am J Orthod Dent<strong>of</strong>acial Orthop 1990;98:117-26. 

14. Burstone C, Farzin-Nia F. Production <strong>of</strong> low friction and colored TMA 

by ion implantation. J Clin Orthod 1995;29:453-61. 

15. Cash A, Curtis R, Garrigia-Majo D, McDonald FM. A comparative 

study <strong>of</strong> the static and kinetic frictional resistance <strong>of</strong> titanium 

molybdenum alloy arch wires in stainless steel brackets. Eur J 

Orthod 2004;26:105-11. 

16. Sioshansi P. Tailoring surface properties by ion implantation. Cleveland: 

Materials Engineering. Penton Publishing; 1987. 

17. Wyko NT1100 Optical Pr<strong>of</strong>iling System [Internet] 2012 Jan 15. Available 

from: http://ppewww.physics.gla.ac.uk/~williamc/NT1100 spec.pdf. 

[Last cited on 2012 April 5]. 

18. Tidy DC. Frictional forces in fixed appliances. Am J Orthod Dent<strong>of</strong>acial 

Orthop 1989;96:249-54. 

19. Pr<strong>of</strong>fit WR. Contemporary orthodontics. 3 rd ed. St Louis: C.V. Mosby; 

2000. 

20. Serway RA. Physics: For Scientists and Engineers. Philadelphia: 

Saunders College Publishing; 1982. 

21. Kapila S, Sachdeva R. Mechanical properties and clinical applications 

<strong>of</strong> orthodontic wires. Am J Orthod Dent<strong>of</strong>acial Orthop 1989;96:100-9. 

22. Andreasen GF, Morrow RE. Laboratory and clinical analysis <strong>of</strong> nitinol 

wire. Am J Orthod 1978;73:142-51. 

23. Eliades T, Eliades G, Athanasiou AE, Bradley TG. Surface characterization 

<strong>of</strong> retrieved NiTi orthodontic arch wires. Eur J Orthod 2000;22:317-26. 

24. Son SY, Nishida S, Hattori N, Jang HD, Son YJ. The effect <strong>of</strong> surface 

treatment <strong>of</strong> TI-6Al-4V alloy specimens. Key Eng Mater 2005;297-300: 

2429-34. 

25. Sioshansi P. improving the properties <strong>of</strong> titanium alloys by ion 

implantation. J Miner Met Mater Soc 1990;42:30-1. 

How to cite this article: Krishnan M, Saraswathy S, Sukumaran K, Abraham 

KM. <strong>Effect</strong> <strong>of</strong> ion-implantation on surface characteristics <strong>of</strong> nickel titanium 

and titanium molybdenum alloy arch wires. Indian J Dent Res 2013;24:411-7. 

Source <strong>of</strong> Support: Nil, Conflict <strong>of</strong> Interest: None identified. 

Author Help: Reference checking facility 

The manuscript system (www.journalonweb.com) allows the authors to check and verify the accuracy and style <strong>of</strong> references. The tool checks 

the references with PubMed as per a predefined style. Authors are encouraged to use this facility, before submitting articles to the journal. 

• The style as well as bibliographic elements should be 100% accurate, to help get the references verified from the system. Even a single 

spelling error or addition <strong>of</strong> issue number/month <strong>of</strong> publication will lead to an error when verifying the reference. 

• Example <strong>of</strong> a correct style 

Sheahan P, O’leary G, Lee G, Fitzgibbon J. Cystic cervical metastases: Incidence and diagnosis using fine needle aspiration biopsy. 

Otolaryngol Head Neck Surg 2002;127:294-8. 

• Only the references from journals indexed in PubMed will be checked. 

• Enter each reference in new line, without a serial number. 

• Add up to a maximum <strong>of</strong> 15 references at a time. 

• If the reference is correct for its bibliographic elements and punctuations, it will be shown as CORRECT and a link to the correct article 

in PubMed will be given. 

• If any <strong>of</strong> the bibliographic elements are missing, incorrect or extra (such as issue number), it will be shown as INCORRECT and link to 

possible articles in PubMed will be given. 

417

Effect of ion‑implantation on surface characteristics of nickel titanium ...

Create successful ePaper yourself

Delete template?

Save as template?