Mk0822

The forced rats were weighed and then injected intraperitoneally with 10% 300 mg/kg chloralic hydras for general anesthesia. A cervical groove was prepared using a round bur with a dental low-speed handpiece on the distal and labial surfaces of 2 incisors just above the gingival margin. The orthodontic nickel-titanium closed coil spring (GRINM, Beijing, China) was ligated between the upper right first molar and both incisors using a 0.20-mm steel ligature. Next, the spring was activated for approximately 1 mm to produce a continuous force of 60 g to move the upper right first molar forward (Figure 1). A force of 60 g was used because the amount of force typically used to move rat molars in the mesial direction is 50-60 g (Gonzales et al., 2009) . In order to enhance retention around the teeth, the ligature wire was secured using bond adhesive (Transbond, 3M Unitek, Monrovia, CA, USA) on the incisors. Rats in the 60 g-ODN group were injected with 50 mL 1.25 mM ODN (MK0822; Selleckchem, Houston, TX, USA) into the buccal groove around the upper right first molar every third day. Rats in the 60 g-NS group were injected with 50 mL NS. Spring retention was evaluated daily to ensure the stability of the applied force. The diet of the rats did not change after the orthodontic device had been applied.