Anchorage miniscrews: a surface characterization study using optical microscopy

The aim of this study was to assess the surface changes in orthodontic miniscrew implants retrieved after usage and compare them with brand-new, as-received control miniscrews.

The study sample consisted of 28 miniscrews from the same manufacturer: Dual Top Anchor system® (Korea) of different diameters and lengths. One brand-new miniscrew served as a control. Surface characterization was carried out using optical microscopy (Leica DM2500M®) and image magnification (×5, ×10 and ×20).

Observations under optical microscopy showed signs of pitting and crevice corrosion mainly at manufacturing defects. Retrieved miniscrew implants displayed larger surface cracks from corrosive attacks (pitting and crevice). Qualitative sample analysis suggested a loss of gloss and texture, giving the surface a dull appearance. Localized pitting was the most frequent form of corrosion observed in our sample.

Despite a smooth appearance to the naked eye, the miniscrews all had crack-like surface manufacturing defects. Examination of the surface of these miniscrews, after usage, evidenced pitting or crevice corrosion principally in the area of enhance corrosion resistance.