The mechanical properties of the extra hard spring arch wire subjected to the artificial saliva

الملخص EN

Aims: To evaluate and compare the value of the mechanical properties of the extra hard spring stain¬less steel arch wire immersed in artificial saliva.

Materials and Methods: The sample consisted of 40 extra hard spring stainless steel arch wires (Remanium, 0.016" × 0.016", Dentarum, Germany) divided into; control wires group and experimental group (ten wires for each group).

The experimental group was immersed in artificial saliva (PH 6.75+ 0.015) ) and incubated at 37 for one, two and four weeks respectively.

The curve of tensile strength for the control and experimental groups was performed us¬ing the tensile testing machine.

The mechanical properties of the arch wire have been derived.

The re¬sults were analyzed using the statistics of descriptive, Anova and Duncan’s Multiple Range Analysis tests.

Results: The results showed that the mechanical properties (ultimate tensile strength, elastic modulus, springiness (springback) ,elastic limit, plastic limit (ductility) of the extra spring hard stain¬less steel arch wire significantly decrease as the immersion time in artificial saliva increase when com¬pared with the control group.

Conclusions: It is recommended not utilize the extra spring hard stain¬less steel arch wire for long periods during orthodontic treatments.

Key words: Yield stress, ultimate tensile, elastic modulus, springiness, elastic limit, plastic limit.