The appearance of orthodontic appliances has been improved by the introduction of tooth coloured brackets. Aesthetic archwires are highly desirable to complement aesthetic brackets in clinical orthodontics. The objective of this study was to characterise the elastic behaviour of aesthetic archwires and determine whether their behaviour was modified following intraoral use. The load-deflection behaviour of five types of coated and uncoated 0.014” NiTi archwires in their as-supplied condition and following 6 weeks of intra-oral use was characterised using 3 point wire bending tests (n=10 per group). Representative archwires from each group were examined using Scanning Electron Microscopy. The results indicated that the archwires behaviour after 6 weeks of clinical use was more unpredictable than that of unused archwires. In addition the retrieved PTFE coated archwires produced lower unloading forces than unused archwires. The force generated by the uncoated and PTFE coated archwires was comparable. The coated archwires undergo significant delamination of the coating after 6 weeks of clinical use. Within the confines of the limitations of this study the clinical implications are that the PTFE coated archwires moved teeth at comparable rates to their uncoated counterparts. However the coating did degrade and the archwires behaved less predictably after 6 weeks of clinical use.
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