RESUMEN
The lower 2(nd) molar eruption is beginning to mesiolingually, then rotate to distobuccally so it has a tendency to be tilted and impacted mesially. Signs and symptoms of impacted 2(nd) molar are similar to impacted 3(rd) molar's. However, treatment plan for impacted 2nd molar is different from that of impacted 3(rd)'s. The former is the preservation and uprighting of 2(nd) molar so that it could act to recovery of mastication, symmetrical facial growth, maintaining the symmetry of dental arch, stable occlusion, while the latter is the extraction of tooth. If the uprighting treatment is planned, most proper protocol of treatment and the additional treatment opition should be applied with consideration for it's crown exposure, present of 3(rd) molar which interrupt the uprighting process, extrusion of opposite tooth. Although it could not improve the esthetic result, it could prevent many dental problems. Therefore, uprighting for impacted lower 2(nd) molar is meaningful treatment.