What Can Clear Aligners Do Efficiently ?
2 min read
A team from Ferrara, Italy, led this research, studying the efficacy of clear aligner orthodontic therapy
To be a member of the study panel, members had to meet at least one of the following inclusion criteria.
Be a member of the ABO, EBO, Italian Board of Orthodontics, Italian Board of Orthodontics Aligner or European Board of Aligner Orthodontic Boards.
Have published more than five research papers on aligners in accredited journals.
More than fifteen years of internationally recognised expertise in the field of aligners.
36 experts who met these criteria were selected and invited to participate by the chair . Of the experts who initially agreed to participate, 6 dropped out, so the survey ultimately collected responses from 30 participants.
What did they find?
Aligners can effectively achieve tipping movements.
Distalisation of maxillary or mandibular molars beyond 2.75 mm is not predictable with aligners.
Aligners are not effective for bodily mesialisation exceeding 2.75 mm.
Bodily movements (translation) of molars beyond 3–3.5 mm cannot be reliably achieved.
Aligners are not effective for bodily intrusion greater than 1.5 mm.
Extrusion movements exceeding 1.5 mm are not predictable with aligners.
Aligners can successfully achieve rotations of less than 10°.
Rotations between 10–20° are highly effective in incisors.
Rotations exceeding 20° are moderately effective in incisors
Premolar and canine rotation less than 10° is highly effective.
Premolar and canine rotation more than 20° is minimally effective.
Molar rotation less than 5° is highly effective
Space closure is effective when movements are limited to ≤1.5° per aligner.
The use of attachments is moderately effective in improving rotation, torque, and distalisation and highly effective in extrusion
Aligners are moderately effective in extraction cases involving 4 premolars
and highly effective in extraction cases involving lower incisor
Aligners are not considered effective for orthopedic correction in growing patients.
Panoramic and lateral cephalometric radiographs, along with a digital setup, are required for effective aligner planning.
Retention is planned for 100% of patients, with fixed retention commonly used, particularly in the mandibular arch and removable for maxillary arch.
This paper explores the predictable limits of tooth movement achievable with clear aligners. By identifying which movements can be achieved reliably and which are less predictable, it offers clinicians a clearer framework for case selection in aligner therapy.
Its real value lies in expectation management both for orthodontists and patients. When cases are selected within these predictable limits, aligner treatment is typically efficient and controlled. When cases fall outside them, the need for refinements, auxiliaries, or alternative mechanics should be anticipated.
Full study:
