Indications and limits of clear aligner therapy: an international modified Delphi consensus study

BACKGROUND: The aims of this study were to gather expert agreement about essential aspects of clear aligner therapy (CAT) and to determine what research areas need further investigation. MATERIALS AND METHODS: A steering committee performed literature selection and compiled a list of 25 statements. This study used a modified Delphi method involving a panel of 23 international orthodontic experts. Six essential areas of CAT were investigated: treatment efficacy, quality of life, side effects, management of growing patients, treatment with extraction, and treatment of periodontal patients. A panel of experts assessed 25 statements using a 5-point Likert scale throughout 3 rounds of the study. A steering committee adjusted statements that failed to achieve consensus through either revision, splitting, merging, or complete removal. RESULTS: After the third round, 22 statements achieved consensus while 3 statements were rejected. The panel agreed that aligners could be used effectively in some types of malocclusions, such as those with mild or moderate crowding or open bite cases. The experts reached a consensus on the biomechanical limits of clear aligners. However, they agreed on the benefits in terms of improved quality of life during treatment and easier maintenance of oral hygiene maneuvers. Regarding specific patient categories, the panelists supported the use of aligners in periodontal patients with tooth migration requiring tipping movements. They also agreed on the advantages of using a rapid palatal expander over aligners in growing patients. CONCLUSIONS: The panel members reached agreement on most topics. However, they acknowledged limitations in the current literature regarding root resorption and orthodontic relapse with CAT compared to fixed appliances. The absence of agreement on treatment duration, effects on skeletal growth, and the management of periodontally compromised patients highlights significant evidence gaps that warrant further research.