Characterization and comparison of as received and clinically retrieved Bio-active™ orthodontic archwires

Figures & data

Table 1. Input parameters for the nanoindentation experiments.

Parameter	Unit	Value	Parameter	Unit	Value
Percent to unload	%	90	Approach distance to store	nm	1000
Surface approach velocity	nm/s	10	Peak hold time	s	10
Depth limit	Nm	500	Surface approach distance	nm	5000
Delta X for finding surface	Μm	−50	Surface approach sensitivity	%	40
Delta Y for finding surface	Μm	−50	Frame stiffness correction	N/m	0
Strain rate target	1/s	0.05	Percent unload in stiffness calculation	%	50
Allowable drift rate	nm/s	0.05	Poisson’s ratio	[-]	0.3
Perform drift test segment	[-]	1	Perform drift correction	1/0	1

Figure 1. XRD pattern of as received and clinically retrieved Bio-active™ archwires.

Figure 2. SEM micrographs of the surface of the upper wires: as received (a), used for 6 weeks (b) and used for 9 weeks (c). From left to right: ant., bic., post. (the 2 μm micrographs are visualized at ×5000 magn., while the 200 nm micrographs are visualized at ×50,000 magn.).

Figure 3. Representative SEM (a) micrograph (×2000 magn.) and EDS spectra (b) of the surface of Bio-active™ archwires.

Table 2. Mean values for the surface elemental composition of the investigated Bio-active™ archwires.

Element [wt.%]	Surface									Error [%]
	As received			Used for 6 weeks			Used for 9 weeks
	ant.	bis.	post.	ant.	bis.	post.	ant.	bis.	post.
Ni	54.7	53.5	52.5	53.2	54.9	53.5	53.3	53.6	53.3	± 0.8
Ti	44.8	46.6	47.0	46.5	44.5	46.2	46.4	45.9	46.4	± 0.8
Fe	0.5	–	0.3	–	0.4	–	–	0.3	–	± 0.8
Cr	–	–	0.3	0.3	0.1	0.3	0.3	0.3	0.3	± 0.8

Table 3. Elemental composition of the anterior region of Bio-active™ archwires as received (surface) and bicuspid area of used for nine weeks (cross-section).

Element [wt.%]	As received ant.		Used for 9 weeks bis.				Error [%]
	1	2	3	4	5	6
Ti	80.3	35.6	45.9	93.4	46.9	46.2	±0.8
Ni	19.7	64.4	54.1	6.6	53.1	53.8	±0.8

Figure 4. SEM micrographs of anterior region (a) of as received (surface) (×5000 magn.) and bicuspid region (b) of Bio-active™ archwires used for nine weeks (cross-section) (×2000 magn.).

Figure 5. LIBS spectra of the investigated Bio-active™ archwires, showing the presence of Fe.

Figure 6. LIBS spectra of the investigated Bio-active™ archwires, showing the presence of Cr.

Figure 7. Indentation hardness (a) and indentation modulus (b) of investigated Bio-active™ archwires.

Figure 8. Anterior segment statistical results for Ni content dynamics.

Note: Different colours indicate statistically significant differences (p < 0.05).

Figure 9. Bicuspid segment statistical results for Ni content dynamics (a) and Ti content dynamics (b).

Note: Different colours indicate statistically significant differences (p < 0.05).

Figure 10. Bicuspid segment statistical results for indentation modulus dynamics (a) and bicuspid segment statistical results for indentation hardness dynamics (b).

Note: Different colours indicate statistically significant differences (p < 0.05).

Figure 11. Posterior segment statistical results for Indentation Modulus dynamics (a) and Posterior segment statistical results for Indentation Hardness dynamics (b).

Note: Different colours indicate statistically significant differences(p < 0.05).

Data availability

All data that support the findings reported in this study are available from the corresponding author upon reasonable request.