Figure 2.

Subcutaneous administration of L(−)-nicotine at a dosage of 1.89 mg per kg gross body weight per day (a) and experimental orthodontic tooth movement (b). To allow a secure injection without potential harm to the animal by inadvertent movements or an otherwise required sedation, a custom-made acrylic box for short-time immobilization (20 s) was used. By means of a NiTi closed coil spring the upper left first and second rat molars (M1/M2) were moved in anterior direction. The contralateral jaw side (wire ligature) served as non-force control (split-mouth design).