Comparative Analysis of Orthodontic Treatment Outcomes With Different Extraction Patterns in Identical Twins: A Case Report With Long-Term Follow-Up.

Orthodontic treatment frequently involves tooth extractions to resolve dental crowding or protrusion and to enhance facial esthetics. The decision on which teeth to extract depends on various factors, including the degree of crowding, the patient's facial growth pattern, and the treatment objectives. The conventional (four-premolar) extraction pattern typically entails the removal of one premolar from each quadrant. However, in specific cases, the single-arch (two-premolar) extraction strategy, involving the symmetrical extraction of two maxillary premolars, can effectively resolve malocclusions with less invasiveness. A pair of identical twins sought orthodontic treatment to address dental crowding. Both patients exhibited nearly identical malocclusions, with severe crowding in the upper arch and mild or no crowding in the lower arch. Each twin underwent orthodontic treatment with a distinct extraction pattern: one received a four-premolar extraction method, while the other was treated with a two-premolar extraction pattern. The treatment outcomes demonstrated that both extraction strategies yielded satisfactory therapeutic effects, including well-aligned dentitions, stable occlusion, and balanced facial profiles. However, there were notable differences in the changes to the torque of anterior teeth between the twins. This case report concludes that while both four- and two-premolar extraction methods can achieve desirable treatment outcomes, their indications differ. The two-premolar extraction approach has a narrowed range of applicability but can be effective when used in appropriately selected cases.