RESUMO
Objective: The purpose of this study was to determine the effect of common methods of sterilization on the tensile strength of Beta titanium, Stainless steel, Australian Stainless steel, Copper Nickel-Titanium, and Nickel-Titanium wires. It also aimed to evaluate the changes in tensile strength values caused by repeated cycles of sterilization. Materials and Methods: A sample of 225 orthodontic wires, i.e., beta-titanium, stainless steel, Australian stainless steel, copper nickel-titanium, and nickel-titanium wires, were collected from different manufacturers. These wires were divided into three groups, which consists of Groups 1, 2, and 3. Four methods of sterilization used in this study were as follows: (i) autoclave (250°F for 20 min), (ii) dry heat sterilization (375°F for 20 min), (iii) ethylene oxide sterilization (54°C for 4 hrs), and (iv) 2.45% acidic glutaraldehyde (10 hrs). Results: The results of this study showed that there was increase in tensile strength of beta-titanium and nickel-titanium wires using autoclave and dry heat sterilization. No statistically significant difference in tensile strength of stainless steel and Australian stainless steel archwires. The tensile strength of copper nickel-titanium wires decreased following 0, 1, and 5 cycles of sterilization. Conclusion: The lack of statistically significant differences established in the study of new and sterilized orthodontic archwires gives us reason to conclude that the orthodontic arch wires can be sterilized because the sterilizing processes do not affect their tensile strength and the orthodontists could thus ensure the maximum safety of their patients.
RESUMO
Aim. To compare and evaluate the static frictional resistance offered by the four different types of ligation methods in both dry and wet conditions and at different durations when immersed in artificial saliva. Material and Methods. Alastik Easy to Tie modules, Super Slick Mini Stix elastomeric modules, Power "O" modules, and 0.009(â³) Stainless Steel ligatures were used to compare the static friction using maxillary canine and premolar Preadjusted Edgewise brackets with 0.022(â³) × 0.028(â³) slot and 0.019(â³) × 0.025(â³) stainless steel wires. Results. The mean frictional resistance for Alastik modules was the lowest and that of Stainless Steel ligatures was found to be highest among the four groups compared and the difference among the four groups was statistically significant (P < 0.005). The mean static frictional resistance in all groups under dry conditions was lower than that under wet conditions. No statistical significant differences were found when the groups were compared at different time periods of immersion in artificial saliva. Conclusion. This study concludes that the Alastik modules showed the lowest mean static frictional forces compared to any other ligation method, though no significant difference was found for different time periods of immersion in the artificial saliva.
