Effect of steam versus dry heat sterilization on the wear of orthodontic ligature cutting pliers

Orthodontic ligature cutting pliers are expensive. Methods of sterilization should be safe considering patient's health as well as lifetime of orthodontic pliers. The purpose of this study was to compare the wear of orthodontic ligature cutting pliers after sterilizing with dry heat or steam autoclave. In this experimental study, thirty ligature cutting pliers from 3 different factories (Dentarum-Germany, RMO and ETM-USA) were sterilized in either dry heat or steam autoclave. The amount of wear at the tip of each plier in both groups was measured with a stereomicroscope and digital photomicrography. Wear was defined as the difference of the initial length and the length after 10, 20, 30 cycles of sterilization measured by the distance from a reference line on the tip of the plier. Three way ANOVA was used to compare wear between the two sterilization groups. P<0.05 was considered as the limit of significance. The amount of wear of the ligature cutting plier's tip after 10, 20 and 30 cycles in dry heat sterilization was 1.0±0.16, 0.98±0.22 and 0.94±0.31 mm respectively. These figures were 1.16±0.15, 1.16±0.13 and 1.15±0.14mm for steam heat sterilization. The higest wear was observed after 20 cycles of sterilization in autoclavce whereas the lowest was seen in dry heat sterilization after 30 cycles. The differences between the two studied groups were statistically significant (P<0.0001). In addition, increasing sterilization cycles decreased the rate of wear in both groups. Based on the results of this study routine autoclaving caused more damage and wear at the tip of the pliers than dry heat sterilization.