Effects of cold chemical (glutaraldehyde) versus autoclaving sterilization on the rate of coating loss of aesthetic archwires: A double-blind randomized clinical trial

Abstract

Objective > The effect of any sterilization methods (cold chemical, or hot) on film removal from coated archwires has not yet been investigated. Thus, we assessed it. Materials and methods > This double-blind randomized clinical trial was performed on 120 observations: 40 macroscopically intact coated archwires from 4 brands were purchased (n = 10 archwires/brand). Five wires from each brand underwent cold and 5 underwent hot sterilization. Wires were applied in 40 non-extractions patients at alignment phase of treatment (one month). Afterwards, 3 inter-bracket segments from each wire were examined microscopically, and the percentage of coating loss was recorded for each segment. Coating losses of the 4 brands and 2 sterilization methods were compared using a two-way ANOVA and a Welch t-test (a = 0.05). Surfaces were also evaluated using scanning electron microscopy. Results > The mean surface coating loss of hot (autoclave) and cold (glutaraldehyde) sterilization methods was 25.6 +/- 28.7 and 28.1 +/- 30.8 percent respectively. The mean surface coating removal of the Ortho Organizers, American Orthodontics, SIA, and Gestenco brands were 24.1 +/- 28.4, 36.7 +/- 36.0, 23.0 +/- 24.4, and 23.6 +/- 28.0 percent, respectively. The two-way ANOVA indicated a lack of overall significant differences among wire brands (P = 0.189) and between sterilization types (P = 0.629). However, the interaction of sterilization and brands was significant (P = 0.005). Conclusions > Within the limitations of this 1-month clinical trial limited to 4 coated NiTi archwire brands only, the average coating removal of examined brands might not differ much, amounting to about 26 within a month. Glutaraldehyde and autoclave sterilization might not affect the average speed of coating loss in all brands, although each sterilization method might be favourable for certain brands.