Ex vivo surface and mechanical properties of coated orthodontic archwires

TY - JOUR

T1 - Ex vivo surface and mechanical properties of coated orthodontic archwires

A1 - Elayyan,Firas

A1 - Silikas,Nick

A1 - Bearn,David

AU - Elayyan,Firas

AU - Silikas,Nick

AU - Bearn,David

PY - 2008/12

Y1 - 2008/12

N2 - <p>This study examined the mechanical and physical properties of retrieved coated nickel-titanium (NiTi) archwires compared with unused samples. Ultraesthetic (TM) 0.016 inch coated archwires (G&amp;H&amp;REG; Wire Company) were investigated. Ten as-received wires were subjected to a three-point bending test using conventional and self-ligating bracket systems. Surface roughness of the coating was measured with a contact stylus profilometer. Optical and scanning electron microscopes were used to assess surface topography. Ten archwires were used in vivo for a period of between 4 and 6 weeks. Retrieved archwires were subjected to the same tests. The percentage of the remaining coating was calculated using digital photography. Coated archwires were used in vivo for a mean period of 33 days. Differences between the mean values of the as-received and retrieved archwires were determined using t-tests.</p><p>In the three-point bending test, with conventional elastomeric ligation, retrieved wires produced a lower unloading force (P &lt; 0.001). Both retrieved and as-received coated archwires produced zero values of unloading force when deflected for 4 mm. When tested using a self-ligating bracket system, retrieved and as-received coated archwires produced the same amount of force (P &gt; 0.05). With surface profilometry, all measured roughness parameters (except R-sm) had greater surface roughness for the retrieved coated archwires (P &lt; 0.05). Under microscopy, retrieved coated archwires showed discolouration, ditching, and delamination. Only 75 per cent of the coating was present in retrieved coated archwires.</p><p>Retrieved coated archwires produced lower unloading force values than as-received coated archwires with conventional ligation. Surface roughness of coated archwires increased after use. Coated archwires have a low aesthetic value, with 25 per cent of the coating lost within 33 days in vivo.</p>

AB - <p>This study examined the mechanical and physical properties of retrieved coated nickel-titanium (NiTi) archwires compared with unused samples. Ultraesthetic (TM) 0.016 inch coated archwires (G&amp;H&amp;REG; Wire Company) were investigated. Ten as-received wires were subjected to a three-point bending test using conventional and self-ligating bracket systems. Surface roughness of the coating was measured with a contact stylus profilometer. Optical and scanning electron microscopes were used to assess surface topography. Ten archwires were used in vivo for a period of between 4 and 6 weeks. Retrieved archwires were subjected to the same tests. The percentage of the remaining coating was calculated using digital photography. Coated archwires were used in vivo for a mean period of 33 days. Differences between the mean values of the as-received and retrieved archwires were determined using t-tests.</p><p>In the three-point bending test, with conventional elastomeric ligation, retrieved wires produced a lower unloading force (P &lt; 0.001). Both retrieved and as-received coated archwires produced zero values of unloading force when deflected for 4 mm. When tested using a self-ligating bracket system, retrieved and as-received coated archwires produced the same amount of force (P &gt; 0.05). With surface profilometry, all measured roughness parameters (except R-sm) had greater surface roughness for the retrieved coated archwires (P &lt; 0.05). Under microscopy, retrieved coated archwires showed discolouration, ditching, and delamination. Only 75 per cent of the coating was present in retrieved coated archwires.</p><p>Retrieved coated archwires produced lower unloading force values than as-received coated archwires with conventional ligation. Surface roughness of coated archwires increased after use. Coated archwires have a low aesthetic value, with 25 per cent of the coating lost within 33 days in vivo.</p>

KW - Archwires

KW - Roughness

KW - Friction

U2 - 10.1093/ejo/cjn057

DO - 10.1093/ejo/cjn057

M1 - Article

JO - European Journal of Orthodontics

JF - European Journal of Orthodontics

SN - 0141-5387

IS - 6

VL - 30

SP - 661

EP - 667

ER -