Comparison of friction forces between stainless orthodontic steel brackets and TiNi wires in wet and dry conditions.
In sliding mechanics, frictional force is an important counter-balancing element to orthodontic tooth movement, which must be controlled in order to allow application of light continuous forces. The purpose of this study was to compare the frictional forces between a stainless steel bracket and five different wire alloys under dry and wet (artificial saliva) conditions. TiNi, TiNiCu, TiNiCo, commercial wires A and commercial wires B with equal dimensions of 0.016×0.022'' were tested in this experiment. The stainless steel bracket was chosen with a slot dimension of 0.022''. Micro-hardness of the wires was measured by the Vickers micro-hardness test. Surface topography of wires was measured by an optical microscope and quantified using surface roughness testing. Static and kinetic friction forces were measured using a custom-designed apparatus, with a 3-mm stretch of wire alloy at a crosshead speed of 1mm/min. The static and dynamic frictions in the wet condition tended to decrease more slowly than those in the dry condition. Therefore, the friction of TiNiCu and commercial wires B would increase. Moreover, these results were associated with scarred surfaces, i.e. the increase in friction would result in a larger bracket microfracture. From the results, it is seen that copper addition resulted in an increase in friction under both wet and dry conditions. However, the friction in the wet condition was less than that in dry condition due to the lubricating effect of artificial saliva.
Department of mechanical engineering, King Mongkut's university of technology Thonburi, 126, Pracha-utid road, Bangmod, Tungkru, Bangkok 10140, Thailand.
Aphinan
A
Phukaoluan
Department of mechanical engineering, King Mongkut's university of technology Thonburi, 126, Pracha-utid road, Bangmod, Tungkru, Bangkok 10140, Thailand; Biological engineering program, King Mongkut's university of technology Thonburi, 126, Pracha-utid road, Bangmod, Tungkru, Bangkok 10140, Thailand. Electronic address: anak.kha@kmutt.ac.th.
Anak
A
Khantachawana
Department of mechanical engineering, King Mongkut's university of technology Thonburi, 126, Pracha-utid road, Bangmod, Tungkru, Bangkok 10140, Thailand.
Pongpan
P
Kaewtatip
Department of orthodontics, faculty of dentistry, Mahidol university, 6, Yothee road, Rajthevee, Bangkok 10400, Thailand.
Surachai
S
Dechkunakorn
Department of orthodontics, faculty of dentistry, Mahidol university, 6, Yothee road, Rajthevee, Bangkok 10400, Thailand.
Niwat
N
Anuwongnukroh
Department of orthodontics, faculty of dentistry, Mahidol university, 6, Yothee road, Rajthevee, Bangkok 10400, Thailand.
Peerapong
P
Santiwong
National metal and materials technology center, 114, Thailand science park, Paholyothin road, Klong 1, Klong Luang, Pathumthani 12120, Thailand.
Julathep
J
Kajornchaiyakul
D003035:Cobalt; D003300:Copper; D003722:Dental Alloys; D006244:Hardness; D006801:Humans; D009532:Nickel; D016910:Orthodontic Brackets; D000070297:Orthodontic Friction; D009969:Orthodontic Wires; D012464:Saliva, Artificial; D013193:Stainless Steel; D014025:Titanium
D003722:Dental Alloys; D012464:Saliva, Artificial; C093972:titanium-nickel-cobalt alloy; D013193:Stainless Steel; D003035:Cobalt; D003300:Copper; D009532:Nickel; D014025:Titanium
Friction force; Orthodontics; Stainless steel bracket; TiNi alloys