The Ethics Committee for Animal Research of the Veterinary School of the University of Teramo (Teramo, Italy) approved the study protocol, which followed the guidelines established by the European Union Council Directive of February 2013 (R.D.53/2013).

Two female sheep, 4–5 years old, were included in the study. Clinical examination determined that all animals were in good general health. Exclusion criteria included general contraindications (pregnancy, systemic disease) to implant surgery and active infection, or severe inflammation in the area intended for implant placement.

The animals were given thiopental (Thiopental, Höchst, Austria) for induction of anesthesia as needed. After oro-tracheal intubation and ventilation, anesthesia was sustained with nitrous oxide oxygen with 0.5% halothane. Physiologic saline solution was administered during surgery for fluid replacement.

The edges of the iliac crests were exposed through a skin incision of 15 cm in length. The skin and facial layers were opened and closed separately.

After dissection of the soft tissues, the bone was exposed and five undersized osteotomic sites were prepared in each (left and right) side of the iliac crest. In the right side of each animal (test group), implant bone sites were prepared using only the pilot drill 1.8 mm in diameter. Ten Expander® 3.8 × 10 mm implants (NoDrill®, Milano, Italy) were inserted in the right side of both animals with a hand control wrench. Maximum insertion torque values were between 45 and 60 N/cm. In the left side of each animal (control group), implant bone sites were prepared using the following burs sequence: pilot drill 1.8 mm in diameter, twist drill 2.8 mm in diameter, and the final drill 3.2 mm in diameter. Ten 3.8 × 10 mm Dynamix® implants (Cortex, Shlomi, Israel) were inserted in the left sides of both animals. Maximum insertion torque values were between 30 and 45 N/cm. The implant drilling procedures were carried out under profuse saline irrigation (1000 rpm). Implants were inserted in cancellous type IV bone.