Background : Orthodontic treatment is a type of in dentistry to obtain a good aesthetic dentofacial appearance by removing the arrangement of dense teeth, correcting deviations in the teeth, correcting the connection between incisors of the teeth and creating good occlusion. One of the component of the tool used in orthodontic treatment is orthodontic wire. Stainless steel orthodontic wire is the most commonly used wire currently in orthodontic treatment. Orthodontic appliance are used inside the oral cavity all the time, in the oral cavity many things can affect the removable ortho, one of which is hot and cold temperatures. The purpose of this study was to determine whether or not the effect of temperature changes on the dimensions of stainless steel orthodontic wire. Method : The type of research conducted in this study is laboratory research that tests laboratory experiments, with a total sample of 20 pieces each divided into 4 groups. The data collection technique in this study is by conducting a comparison before and after treatment on the sample. The statistical test used is Kruskal wallis to determine the significant differences in each group to the temperature of the treatment Result : The results of this study indicate a significant difference in temperature in each group, with a value of p = (p <0.05). based on the results of these studies it can be concluded that there is an influence of temperature 15 ° c, 37 ° c, 45 ° c to diameter of the ortodontic wire 0.6 mm stainlees steel on the removable ortodontic appliance