Figure 2.

The 30-g orthodontic force application system used to assess the effects of nicotine on orthodontic tooth movement and bone remodeling in rats. A, A pre-made cast for image-based training and practice, with a 5-mm nickel-titanium (Ni-Ti) closed-coil spring tied with a 0.012-inch stainless steel ligature wire and a loop for the tension gauge. B, Placement of a sharp, labial-cervical, edge-shaped groove in the gingival third of the maxillary central incisors for prevention of ligature displacement. C, A 5-mm Ni-Ti closed-coil spring placed between the first molar and the two incisors, which are splinted for reinforcement of the anterior anchorage. D, Self-etching, automix, dual-cured permanent adhesive resin cement was light-cured to both ends of the ligature wire to secure the Ni-Ti coil spring. E, Measurement of the 30-g orthodontic force using a dial tension gauge. F, Intraperitoneal injection in the left groin area to induce anesthesia for insertion of the orthodontic appliance.