Periodontal disease is the chronic inflammation of the soft and hard tissues that support and strenghten the tooth which gradually leads to tooth loss. Severe forms of periodontitis represent a major public health issue, with over a billion people worldwide affected by the disease. Stage IV periodontitis is the most severe form of the disease and it is characterized by ≥ 5 mm interdental attachment loss, radiographic bone loss as well as the loss of more than 5 teeth due to the disease. In addition, there is masticatory dysfunction and pathological tooth mobility, as well as severe defects of the alveolar ridge, which consequently leads to the occurence of occlusal collapse with the presence of pathologic tooth migration and flaring present in the anterior region or loss of support in the posterior region. Stage IV periodontitis threatens the survival of not only individual teeth, but the entire dentition as well. Many patients suffering from stage IV periodontitis are interested in combined periodontal and orthodontic therapy, due to both the loss of function as a consequence of pathologic tooth migration and the aesthetic changes that the latter brings with it. Previous research has confirmed that the application of orthodontic forces has little to no statistically significant effect on a healthy, normal or reduced periodontium. However, the effect of orthodontic forces on the inflamed periodontium may accelerate the progression of periodontal disease. For this reason, before commencing the regenerative periodontal surgery as well as the orthodontic therapy, it is necessary to complete the initial non-surgical treatment. The implemented orthodontic therapy must not jeopardize the short-term and long-term goals of periodontal surgery and must be properly integrated into the entire course of therapy. It is precisely the time at which orthodontic therapy should be started which is the subject of investigation within the scientific community.