الفهرس 
Introduction.Only 14 pages are availabe for public view
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Abstract
With the significant increase in adult orthodontic treatment and the emphasis on esthetics in our current era, there is a growing demand for esthetic orthodontic appliances. However it is important to note that each of the known esthetic orthodontic appliances such as aligners and lingual braces have demonstrated various limitations and proved that labial conventional appliances are indispensable. Consequently, there is a need for labial esthetic brackets and wires. Over the years ceramic brackets have been used as a practical and reasonable alternative to traditional metal brackets. Additionally, coated metal archwires whether Teflon coated or epoxy coated are the most commonly used type of esthetic archwires. Therefore, it is imperative to conduct a comprehensive investigation into the clinical efficiency, surface and mechanical properties of these coated metal archwires to weigh their pros and cons.
This study was divided into two parts, the first being a randomized clinical trial and the second part is an in vitro study. Surface and mechanical properties of epoxy coated archwires were investigated such as friction, surface roughness, coating retention and ultimately the effect these properties have on clinical efficiency in terms of alignment efficiency and relief of upper anterior crowding. Moreover patient satisfaction with epoxy coated nickel titanium archwires was evaluated. In this randomized clinical trial 26 patients were recruited and a total of 23 patients were analyzed, with equal number of patients enrolled in either control group (group A) or study group (group B). All patients fell within age range from 18 to 30 years and exhibited mild to moderate crowding in the upper arch, they had no prosthetic restorations or enamel anomalies that may interfere with standard bonding procedures of ceramic brackets. Also patients having diseases that might affect tooth movement were excluded from the trial.
Patients in both groups received ceramic brackets 0.018 inch slot size, Roth prescription, patients in (group A) received conventional noncoated superelastic nickel titanium archwires with wire sequence 0.014, 0.016, 0.016X0.022 inches supplied by Ortho Technology while patients in (group B) received tooth tone coated nickel titanium archwires supplied by the same manufacturer and with the same wire sequence. In both groups, each wire was left in place for four to five weeks with alginate impressions taken at T0 (pretreatment) and after every wire size removal to assess clinical efficiency. Alginate impressions were then poured and converted into digital models. Digital models were then scanned and Little Irregularity Index was measured to assess rate of relief of crowding at T0, T1, T2 and T3. These measurements were recorded twice by the same investigator and a third time by a fellow colleague. In addition participants in (group B) were provided by a Visual Analogue Scale to assess coating stability and patient satisfaction.
Retrieved wires were disinfected and wire specimens were then prepared for further analysis. Friction was investigated using a Universal Testing Machine, while surface roughness was investigated using Atomic Force Microscope. Furthermore Scanning Electron Microscope was employed to assess surface topography of epoxy coated archwires.
The outcomes of the clinical study revealed no statistical difference between both groups regarding clinical efficiency in alleviating anterior crowding in addition to excellent inter and intra examiner reliability when using LII to measure rate of relief of crowding. Patients reported overall moderate patient satisfaction with the coated wires after clinical use, which also correlated by the VAS scores given by the primary examiner. Retrieved coated wires showed areas of delamination and coating loss. Surface roughness of uncoated as received wires in (group A) was found to be higher than that of coated as received wires in (group B), while after clinical use surface roughness of retrieved wires in both groups significantly increased with that of (group B) significantly higher than (group A).