الفهرس 
List of ContentsOnly 14 pages are availabe for public view
 |  | from | 137 |  |  |
| | | from | 137 | | |
Abstract
This study evaluated the flexural strength, surface roughness and coating stability of two different coated archwires as received and after clinical use.A total number of 20 of maxillary superelastic coated NiTi wires were used in this study and equally divided into two groups, group1: Teflon coated wires (Ortho Organizers) and group 2: Epoxy resin coated wires (American Orthodontics- Everwhite). These wires were subjected to three point bending test to determine their flexural strength (load of deflection). Surface roughness was investigated using contact stylus profilometer. To assess surface topography, Optical and Scanning Electron Microscope (SEM) were used. Then the wires were used in vivo for period between 4-6 weeks. Retrieved archwires were subjected to the same tests. The data were analyzed using Mann-Whitney test, paired t test and Wilcoxon Signed Ranks at 5% level of significance.Regarding three point bending test, both groups showed increase in flexural strength during loading and unloading after clinical use with higher values for EverWhite group. With surface profilometry, all measured roughness parameters showed significant increase in both groups after treatment. Under microscopy, retrieved wires from both groups showed ditching, delamination and discoloration, with nearly 15% of coat loss in Teflon group (Ortho Organizers) and 11% cot loss in Epoxy resin (Ever White) group.Retrieved coated archwires produces higher loading and unloading forces than as received. Everwhite group showed increased in flexural strength at various loading and unloading points than Teflon group (Ortho Organizers) which may become less suitable for the initial leveling phase. Teflon group (Ortho Organizers) showed increased in surface roughness and coat loss than Everwhite group after 4-6 weeks intraoral which impair oral health and esthetic of the patients.