A Comparative Evaluation of Surface and Elemental Changes in Stainless Steel and Titanium Orthodontic Miniscrew Implants: A Multiarm Randomized Controlled Trial.

Purpose: To compare and quantify the surface changes seen in two of the most commonly used orthodontic miniscrew implants (MSIs) after their clinical use.

Materials and methods: In total, 40 MSIs (20 titanium [Ti] and 20 stainless steel) were retrieved from the maxillary arch of 20 patients (13 females and 7 males) after their intended use. The patients were 18 to 27 years old (mean age = 22.4 ± 3.83 years). As-received MSIs were used as the control. All the MSIs were analyzed under a scanning electron microscope (SEM) (Evo 18, Zeiss) for the characterization of their morphologic condition, including blunting of tip, surface defects, and corrosion. Furthermore, an energy dispersive x-ray (EDX) microanalysis was carried out to study the changes in surface characterization.

Results: When captured using the SEM, the new Ti and stainless steel MSIs demonstrated a relatively smooth surface with no surface defects. However, the retrieved Ti and stainless steel implants showed a statistically significant increase in surface defects (both corrosion and cracks). The retrieved Ti MSIs (115.31 ± 24.38 μm) showed four times more blunting compared to the retrieved stainless steel MSIs (29.74 ± 8.56 μm), with the latter showing two to three times more surface corrosion.

Conclusions: The clinical usage of MSIs had pronounced effects on both the Ti and stainless steel MSI alloys in terms of changes in the surface characteristics. While stainless steel MSIs are more susceptible to surface corrosion, Ti MSIs exhibit greater alterations in the form of tip blunting and cracks in the screw threads.