Method: Twelve mongrel dogs were used. Mandibular third premolars (P3) were extracted and mandibular mini-implants were placed bilaterally. A simplified, buccal-only corticotomy (SC) was compared to cortical bone injury produced by a corticotomy facilitated (CF) technique on the buccal and lingual surfaces. The second premolars (P2) were moved distally using NiTi coil springs aided by mini-implant anchorage, 48 Mini-implants (NEODENT, Curitiba – BRASIL) were inserted, with a diameter of 1.3mm and a length of 9.0mm. The dogs were scanned with Cone Beam Computed Tomography (i-CAT scanner-Imaging Sciences International, Hatfield, PA EUA) on the same day of the surgery and again at the end of 11 weeks. Clinical measurements were taken with digital Boley caliper.
Result: In this study, the P2 on the SC side moved significantly more rapidly (p<0.05) than did the surgically unassisted control, but showed no significant difference (p>.05) when compared to the CF side. The mean distal movement of P2 was 0.99mm in the control, 4.39mm in the SC, and 4.48mm in the CF. The mean displacement of the loaded mini-implants was 0.25mm.
Conclusion: Rate of clinical tooth movement was the same comparing the two techniques, self-drilling titanium alloy mini-implants with small diameter (1.3mm) are able to resist immediate loading (250g), however some movement and displacement do in fact occur.