SANTOS, Rogério Lacerda dos    PITHON, Matheus Melo. Use of W arch for patients allergic to nickel. RGO, Rev. gaúch. odontol. (Online) []. 2011, 59, 3, pp. 477-481. ISSN 1981-8637.

Objective The W arch is commonly used to correct posterior dental cross-bite. With the emergence of stainless steel wires made of low nickel content, these wires have become the best choice in producing these appliances for patients with an allergy to this ion. The objective of this study is to test the hypothesis that there is no difference between stainless steel wires and low-nickel stainless steel wires with regard to their mechanical behaviour. Force, resilience, and modulus of elasticity produced by W arches were assessed. Methods Sixty W arches were made, thirty of each type of alloy, fifteen for each wire thickness. All the arches were submitted to mechanical compression test by using an EMIC DL-10000 machine simulating activations of 4, 6, 9, and 12 mm. Analysis of variance (ANOVA) with multiple comparisons and Tukey's test were employed (p< 0.05) to assess force, resilience, and modulus of elasticity. Results The groups using the 0.036 inch wire produced statistically (p<0.05) higher levels of force, resilience and elasticity modulus when compared to the arches using the 0.032 inch wire for both alloys. Statistically significant differences were found for the forces generated between the 0.032 and 0.036 inch thicknesses (p<0.05). Conclusion: The low-nickel stainless steel alloy had higher force, resilience, and modulus of elasticity compared to wires made of conventional stainless steel alloy.

: Orthodontic appliances.; Hypersensitivity.; Malocclusion..