The mini-implants of different base materials were machined in
order to have the sameshape (Fig. 1). The SEMevaluation demonstrated
that all of the experimentalmini-implants presented a cylindrical screw
design, a hexagonal head, 6.0 mm in active length, 2.0 mm in diameter,
a total of 9 pitches, and 0.51 mmbetween the top of the pitches (Figs. 1
and 6a).