ABSTRACT
OBJECTIVE: The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. METHODS: 0.016-inch nickel titanium (NiTi) wires and 0.017 x 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0degrees, 5degrees, and 10degrees. Upper maxillary premolar brackets (Clippy-C(R)) with a 0.022-inch slot were selected for the study and a tensile test was performed with a crosshead speed of 5 mm/min. The maximum static frictional forces and kinetic frictional forces were recorded and compared. RESULTS: The maximum static frictional forces and the kinetic frictional forces of coated wires were equal to or higher than those of the uncoated wires (p < 0.05). The maximum static frictional forces of rhodium-coated wires were significantly higher than those of polymer-coated wires when the angulations between the brackets and wires were set to (i) 5degrees in the 0.016-inch NiTi wires and (ii) all angulations in the 0.017 x 0.025-inch SS wires (p < 0.05). The kinetic frictional forces of rhodium-coated wires were higher than those of polymer-coated wires, except when the angulations were set to 0degrees in the 0.016-inch NiTi wires (p < 0.05). CONCLUSIONS: Although the frictional forces of the coated wires with regards to aesthetics were equal to or greater than those of the uncoated wires, a study under similar conditions regarding the oral cavity is needed in order to establish the clinical implications.
Subject(s)
Bicuspid , Esthetics , Friction , Mouth , Nickel , Stainless Steel , TitaniumABSTRACT
Aim: To evaluate the changes in surface roughness and frictional features of '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 profilometry. Frictional forces were studied in a universal testing machine. Surface roughness of arch wires were determined as Root Mean Square (RMS) values in nanometers and Frictional Forces (FF) in grams. Statistical Analysis Used: Mean values of RMS and FF were compared by Student's 't' test and one way analysis of variance (ANOVA). Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical profilometry demonstrated reduction of 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 of 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 of 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 of NiTi and TMA wires when used in combination with stainless steel brackets, which needs further investigations.
ABSTRACT
The purpose of this study was to amount of the frictional forces with the brackets and wires, ligation methods, dry/wet, offsets, interbracket distances, velocity and to compare them each other by different conditions. This study tested 0.018" x 0.025" slot sized 8 types of orthodontic bracket systems and 0.016", 0.016" x 0.022" sized stainless steel, NiTi, Cu-NiTi orthodontic wires. One cuspid bracket were positioned on the slide glass and archwire was engaged into bracket and ligated with elastomeric modules. The values of frictional forces were measured with the Instron universal testing machine. The results were as follows; 1. Polycrystalline ceramic bracket had the highest mean frictional forces and followed and by ceramic reinforced plastic bracket, metal bracket, plastic bracket with metal slot, monocrystalline ceramic bracket, single bracket, self-ligating bracket, friction free bracket in descending order. The self-ligating bracket showed low frictional forces in the round wires and high frictional forces in the rectangular wires. 2. Stainless steel wires had the least frictional forces and followed by NiTi, Cu-NiTi wires in descending order. Round wires had lower frictional forces then that of rectangular wires. 3. The stainless steel ligation method had significantly greater mean frictional forces them the elastomeric module ligation method. 4. Artificial saliva statistically increased the frictional forces in stainless steel wire, NiTi wire and Cu-NiTi wire. 5. There was a statistically significant difference with offset change. 6. There was no statistically significant difference with interbracket distance in stainless steel wires but a significant difference in NiTi wires as the interbracket was decreased.