Evaluation of the Perceived Experience of Patients Treated With Aligners With Two Different Attachment Placement Times: Randomised Controlled Clinical Trial

: The study was approved by the Institutional Review board of the Catholic University of the Sacred Hearth, Rome, Italy (prot. n. 17048/23). All adult patients with class I and II malocclusion referred to the Fondazione Policlinico Universitario Agostino Gemelli will be consecutively enrolled for this study. All patients will be treated with Biomax Nuvola aligners built based on the individual patient's characteristics. The number of aligners and the number/ type of attachments will be chosen on the basis of the individual malocclusions.

Patients will be randomly allocated in two different groups: the study group includes patients following the delayed protocol (DP), while the control group is composed of patients' following the conventional protocol (CP). The aligner will be changed every 15 days, so the attachment placement in the DP will be performed around 30 days from the beginning of the clear aligner treatment. The modified OHIP Italian version has 20 questions categorized into 7 sections, concerning the limitation generated by deterioration of oral health in relation to clear aligners: functional, pain, psychological discomfort, physical or psychological or social disability, and handicap. The answers range from 0 (never) to 4 (very often). Possible categories are: never (0), rarely (1), sometimes (2), habitually (3), and very often (4). Low scores indicate better self-perception of quality of life. The customised questionnaire has 9 questions, concerning the limitation generated by discomfort caused by attachments. For 8 questions, the answers range from 0 (never) to 4 (very often). Possible categories are: never (0), rarely (1), sometimes (2), habitually (3), and very often (4). Low scores indicate better self-perception of quality of life. For the last question the answer is based on NRS scale, in fact it ranges from 0 to 10. Lower score indicates less pain perceived by the patient. The questionnaires will be filled out at different phases of orthodontic treatment, specifically: at the delivery of the first aligner, after 3 and 7 days; at the delivery of the third aligner, after 3 and 7 days. The survey scheduling is arranged according to White, who stated that the patients' perception of pain and discomfort occurred within 7 days after the beginning of the orthodontic treatment; then, patients' quality of life tends to return to a baseline condition.

The study will be single-blind, because the person collecting the results and making the assessments will not know which treatment was used. In fact, the patient will anonymously submit the answers to the questionnaires uploaded on Microsoft Form, using an acronym that will be provided to him/her by the clinical operator. In this way, the person collecting and analysing the data will not know to which group the patient who sent the answers belongs.