Efficacy of Anti-Rusting Agents on Sterilization of Instruments used in Orthodontic Practice

Autoclaving (a process of sterilization) of instruments can lead to rust formation and corrosion especially the cutting instruments because they have a carbide steel tip. The aim of this study was to check the microbial load of instruments after treatment with any of these agents viz. sodium hypochlorite, vinegar, lemon and coconut oil followed by autoclaving and to assess the instruments for corrosion treated by these above mentioned agents followed by autoclaving. A sample of twenty five orthodontic pliers and cutters were selected for evaluation. They were divided into five groups depending on the agent used. After ultrasonic cleaning of these pliers, they were immersed in the respective solutions for 10 minutes, dried and then subjected to autoclaving. Microbial swabs were collected at two stages: before treating the instruments(T0) with anti rusting agents and after autoclaving(T1). Quantitative culture was performed using standard technique. The working edge of each instrument was examined visually on the amount of corrosion seen. The mean difference in colony forming units of each group were sodium hypochlorite-48.6, vinegar-32.2, coconut oil-31.4, lemon-7.4 and control group-16.8. In this study, use of additive agents like sodium hypochlorite, vinegar, lemon and coconut oil did not alter the process of sterilization, wherein, the CFU’s of all the four experimental groups were similar to the control group. Visual examination reveals that the anti-rusting property of coconut oil is far superior compared to all other agents used.

STRENGTHENING OF CARBIDE STEEL SURFACE BY TUNGSTEN CARBIDE POWDER BY PLASTIC DEFORMATION

The use of the technology of combined electromechanical processing, consisting of a high-temperature plastic deformation mode, when tungsten carbide powder is implanted into the surface of carbon steel, and a high-temperature thermal hardening mode, during which tungsten carbides are partially dissolved in the austenite of steel up to the limit of its saturation with tungsten, provided a gradient wear-resistant three-layer highly dispersed structure as a result of the decomposition of supercooled austenite oversaturated with tungsten. The results of tribotechnical tests of cylindrical specimens by the normalized method are presented.