Impaction of mandibular second molars should be resolved as soon as possible once diagnosed, since it may lead to many functional, periodontal, hygienic and endodontic problems. Treatment options for impacted second molars include orthodontic-assisted eruption following surgical exposure, surgical uprighting and, in some cases, surgical extraction with possible subsequent implant placement if the tooth is deemed non-restorable or the patient prefers an implant restoration. This case report describes the orthodontic treatment of a 21-year-old woman with maxillomandibular protrusion and impacted bilateral mandibular second molars. The Physiologic Anchorage Spee-wire System (PASS) was adopted due to its innovative strategy of physiological anchorage control and unique design involving the multilevel low-friction (MLF) bracket and cross buccal tube (XBT). After 22 months of treatment, a well-aligned dentition, a normal functional occlusion and a harmonious facial profile were obtained, and impaction of the bilateral mandibular second molars was finally resolved. This case report demonstrates a simple and efficient solution to dental impaction. The PASS technique is superior to other preadjusted straight wire appliances in the treatment of maxillomandibular protrusion cases without auxiliary anchorage devices, and the mandibular buccal tube involved in the PASS technique can assist in uprighting the impacted mandibular second molars with NiTi round wire and minimising oral discomfort for the patient.