Clear aligners have changed orthodontics: a series of nearly invisible trays nudges teeth into position, no brackets or wires. But aligners work from a digital simulation — software predicts how each tooth will move, and real teeth do not always follow the script.
One of the hardest movements is rotation: turning a tooth around its own axis, like straightening a twisted tooth. A 2025 systematic review in the Dentistry Journal examined how well clear aligners deliver the rotations they promise.
What the study examined
Researchers from the University of Cagliari, led by Dr. Giulia Benedetti, searched seven databases through July 2025 for studies measuring rotational accuracy with clear aligners. They accepted only studies using 3D digital model superimposition — the gold-standard way to compare the planned position with the actual result.
Twelve studies made the cut (one randomized trial, eleven non-randomized), all in adults. They measured percent accuracy, how far short rotations fell, and average error in degrees.
The headline number: about 65% accuracy
Reported rotational accuracy ranged from 36% to 85%, averaging around 65%. The average shortfall ranged from 0.7 to 4.5 degrees, and the mean error was about 2.3 degrees. In plain language: if your plan calls for a tooth to rotate a certain amount, roughly two-thirds of that rotation tends to happen as planned, and the rest often needs a correction round — called refinement — to finish.
Tooth shape mattered. Incisors and molars were most predictable; upper canines and premolars were least reliable. That makes sense: canines and premolars have rounded cross-sections, which are harder for a smooth plastic tray to grip and turn.
Attachments and other tricks: helpful, but inconsistently proven
To improve results, providers use attachments — tiny tooth-colored bumps that give the aligner something to push against — plus techniques like slenderizing between teeth to make room and staging (limiting each tray to about 2 degrees of rotation).
The review found these helpers widely used, but the evidence that they consistently improve rotational accuracy was inconsistent. The takeaway: the tools help in some cases, but none is a guaranteed fix — success depends on planning, the specific teeth, and the patient wearing the trays as directed.
What this means for you as a patient
If you are considering clear aligner therapy, the review’s message is reassuring — as long as expectations are honest:
- Refinement is normal. The first round of trays gets you most of the way; a second round fine-tunes the rest. That is how the system is designed to work, not treatment failing.
- Your teeth matter more than the brand. Rounded teeth rotate less predictably. A good provider tells you this up front instead of promising the simulation will happen exactly.
- Wearing them as directed is critical. Across aligner research, results track with wear time — compliance, planning, and case selection are the main drivers of success.
- The plan matters. Because accuracy varies by tooth and movement, the doctor’s planning skill — staging, attachments, when to call for refinement — is a bigger factor than patients often realize.
Clear aligner therapy from a prosthodontist’s perspective
Dr. Leila Nikpour offers clear aligner therapy at Expert Dental Group in Roseville. As a prosthodontist, she plans tooth movement with the final result in mind — not just straight teeth, but a bite that functions well and teeth positioned for long-term health. If your case also involves crowns, veneers, or implants, that planning happens together.
One common confusion to clear up: Dr. Nikpour is a clear aligner therapy provider, not an Invisalign provider. Patients often search for the Invisalign name, and the research above covers clear aligner systems broadly — the rotational-accuracy findings come from studies across multiple aligner brands. What matters is the provider’s planning and follow-through, whatever system is used.
At your consultation, Dr. Nikpour will evaluate whether your case fits aligners — including which teeth need rotation and how predictable those movements are — and set an honest timeline that accounts for a possible refinement round. That is the approach the evidence supports: realistic planning beats optimistic simulations.
The bottom line
The 2025 Benedetti review gives a clear-eyed number: clear aligners achieve about 65% of planned rotations on average, with front teeth more predictable than canines and premolars. Refinement closes the gap. The system works in stages — and the provider’s planning makes the difference.
References
- Benedetti G, Sicca N, Lopponi G, Dettori C, Verdecchia A, Spinas E. Evaluating the clinical success of clear aligners for rotational tooth movements in adult patients: a systematic review. Dent J (Basel). 2025. DOI: https://doi.org/10.3390/dj13100440. PubMed: https://pubmed.ncbi.nlm.nih.gov/41149087/
Frequently Asked Questions
How accurate are clear aligners for rotating teeth?
A 2025 review of 12 studies found rotational accuracy ranged from 36% to 85%, averaging around 65%. Incisors and molars were most predictable; upper canines and premolars least reliable.
Do I need a second round of aligners (refinement)?
Often, yes. Because aligners don’t achieve 100% of planned movements on the first pass, refinement is a normal part of treatment — not a sign something went wrong.
Which teeth are hardest to rotate with clear aligners?
Canines and premolars, whose rounded cross-sections are harder for the aligner to grip.
Do attachments guarantee better results?
No. Evidence for their benefit was inconsistent. Treatment planning and wearing the aligners as directed matter more.
Can a prosthodontist provide clear aligner therapy?
Yes. Prosthodontists like Dr. Leila Nikpour plan tooth movement with bite function — and any needed crowns or implants — in mind.
Considering clear aligner therapy? Call Dr. Leila Nikpour at Expert Dental Group, (916) 888-1646 — 5070 Foothills Blvd, Suite 2, Roseville, CA 95747. Open Mon–Fri 9–6, Sat 9–1.