Effectiveness of Guava Leaf Extract (Psidium guajava L.) as Corrosion Inhibitor of Stainless Steel Orthodontic Wire

Abstract

Stainless steel orthodontic wire is one of the wires used in orthodontic treatment. This wire is subject to corrosion. One of the efforts to inhibit corrosion is the addition of corrosion inhibitors. Guava leaves can be used as corrosion inhibitors because they contain active tannin compounds that can inhibit corrosion. This study aimed to analyze the effectiveness of guava leaf extract as a corrosion inhibitor for stainless steel orthodontic wire.This research used 0.16x0.22” stainless steel orthodontic wire from Ormco brand which was cut 40 mm long. 20 pieces of stainless steel wire were divided into 4 groups, namely the group that was soaked in saliva without guava leaf extract (control), saliva, and guava leaf extract 200 ppm, 600 ppm, and 1000 ppm. All wires were weighed before and after immersion. The wire immersion was carried out in an incubator at a temperature of 370 C for 10 days. The corrosion rate of the wire is calculated by the weight loss method. Then proceed with calculating the value of the effectiveness of the inhibitor.The results of this study showed the average corrosion rate of the saliva-soaked group was 0.159 mpy, the saliva-soaked group and guava leaf extract 200 ppm 0.037 mpy, the saliva-soaked group and guava leaf extract 600 ppm 0.033 mpy, and the saliva-soaked and guava leaf extract group guava leaf extract 1000 ppm 0.023 mpy. The results of the kruskal-wallis analysis showed that there was a difference in the corrosion rate between the groups soaked in saliva and guava leaf extract (p<0.05).The effectiveness value of guava leaf extract is effective in inhibiting the corrosion rate with the highest effectiveness of 85.53% Keywords: Corrosion Inhibitor, Stainless Steel Orthodontic Wire, Guava Leaf Extract.