When planning orthodontic treatment for a patient with periodontitis, it is crucial to assess and prevent the risk of worsening periodontal disease and conditions. Similarly, careful consideration must be given to the risk of worsening of muco-gingival conditions in sites at high risk of gingival recession. Therefore, an examination of periodontal status and an analysis of risk factors must be integral parts of the diagnostic and prognostic assessment prior to planning orthodontic treatment for a patient with periodontitis. Treatment should be planned only once the goals of periodontal therapy have been achieved and the disease is under control. Furthermore, assessing the patient's phenotype at the baseline must be part of the preliminary analysis to prevent tooth movement from worsening the initial condition. Indeed, sites exhibiting a thin phenotype—particularly when associated with a highly buccal tooth position and root prominence—may be more prone to recession and dehiscence during orthodontic movement.