Adult patients with skeletal Class Ⅲ and vertical growth pattern often present with periodontal soft and hard tissue defects in the mandibular anterior region, which makes orthodontic treatment alone challenging and high-risk. This article reports an adult patient with skeletal Class Ⅲ, vertical growth pattern and mandibular anterior alveolar bone dehiscence, who achieved significant improvements in both facial profile and occlusion, with stable therapeutic results through a periodontics-orthodontics-orthognathic surgery multidisciplinary treatment approach. This case highlights that appropriate periodontal intervention can effectively reduce treatment risks and improve treatment outcomes and stability for orthodontic patients with compromised periodontal conditions.