Synergistic effect of wire bending and salivary pH on surface properties and mechanical properties of orthodontic stainless steel archwires

Progress in Orthodontics

Table 1 Surface roughness, Young’s modulus, and maximum force of bent/straight wires before and after immersion

Groups		Surface roughness ×10⁻² (μm)			Mean flexural young’s modulus (GPa)	Mean Maximum force (N)
Groups		Ra-value	Ra	Rz	Mean flexural young’s modulus (GPa)	Mean Maximum force (N)
1 (pH 5.6)	Bent	24.1 ± 4.5	30.2 ± 5.7	117.3 ± 43.4	295 ± 46.98	32.5 ± 3.24
1 (pH 5.6)	Straight	11.1 ± 2.5	30.2 ± 5.7	117.3 ± 43.4	505 ± 38.34	27.9 ± 1.07
2 (pH 6.6)	Bent	18.3 ± 3.8	11.5 ± 1.5	81.2 ± 4.8	300 ± 46.72	31.4 ± 5.86
2 (pH 6.6)	Straight	9.4 ± 2.9	11.5 ± 1.5	81.2 ± 4.8	502 ± 52.48	27.6 ± 1.40
3 (pH 7.6)	Bent	20.5 ± 4.2	14.0 ± 0.9	78.8 ± 8.5	242 ± 35.07	29.2 ± 7.43
3 (pH 7.6)	Straight	10.1 ± 2.4	14.0 ± 0.9	78.8 ± 8.5	485 ± 92.66	27.2 ± 3.00
4 (Control)	Bent	17.9 ± 2.2	4.4 ± 0.6	28.4 ± 6.8	345 ± 85.90	32.5 ± 3.72
4 (Control)	Straight	8.2 ± 0.9	4.4 ± 0.6	28.4 ± 6.8	496 ± 18.62	28.4 ± 0.42

Mean roughness (Ra-value), mean flexural Young’s modulus, and mean maximum force of bent/straight wires as well as mean roughness (Ra and Rz) of straight wires before (control group 4) and after immersion in artificial saliva at pH 5.6, 6.6, and 7.6 (experiment groups 1, 2, and 3). Data are shown as mean ± SD