Evaluation of IPR and Attachments on Rotational Tooth Movement in Clear Aligner Therapy

Effects of Interproximal Reduction and Attachment Application on Effectiveness of Rotational Tooth Movement in Clear Aligner Therapy

This study is testing whether clear aligners (Invisalign®) can help fix teeth that are rotated. The researchers want to learn if using two common methods-interproximal enamel reduction (IPR) and attachments-makes rotation correction more successful.

Participants in the study will wear custom-made aligners for about 20 to 22 hours every day. They will switch to a new set of aligners every 2 weeks.

The study will look at tooth movement over time by using a digital planning tool called ClinCheck®, which helps plan and measure how much teeth have moved.

The researchers want to answer three main questions:

Do Invisalign® aligners work well for correcting rotated teeth?

Does IPR help improve rotation correction?

Do attachments help improve rotation correction?

The goal is to understand whether these tools work better together or separately to move teeth into better alignment.

This study is about clear aligners, which are plastic trays that gently move teeth. The researchers want to know how well aligners can fix teeth that are rotated (turned out of their normal position). They also want to test whether two common tools-interproximal enamel reduction (IPR) and attachments-help aligners work better when correcting rotated teeth.

IPR means gently shaving a small amount of enamel between teeth to make space for movement.

Attachments are small, tooth-colored bumps added to teeth to help the aligners grip better and apply more force.

The study includes 35 participants who are being treated with Invisalign® clear aligners. All of them have full adult teeth (except wisdom teeth), mild to moderate crowding, and a type of bite called Class I malocclusion.

Participants wear their aligners for 20 to 22 hours a day, changing to a new set every 2 weeks. The average treatment includes about 18 aligners.

Each participant had a digital scan of their teeth taken at the beginning using an iTero Element® scanner. This scan was used to design a personalized treatment plan using ClinCheck® software, which predicts how the teeth should move.

During treatment, researchers place:

Rectangular attachments on some front and back teeth to improve control

Optimized attachments on teeth that are rotated more than 0.5°, especially premolars and canines

Inclusion Criteria:

Adults with full permanent dentition (excluding wisdom teeth)

Angle Class I malocclusion

Mild to moderate crowding in the upper and lower arches

Planned treatment with clear aligners for both jaws

Rotated teeth within the correction limits recommended by Align Technology®

Willing and able to wear aligners for 20-22 hours per day

Able to attend follow-up visits every 2 aligners (~4 weeks)

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Exclusion Criteria:

Previous orthodontic treatment

Need for additional orthodontic appliances (e.g., elastics or rubber bands)

Periodontal disease or other active oral health problems

Presence of prosthetic dental work (e.g., crowns or bridges)

Need for tooth extraction during aligner treatment

Medical conditions that may interfere with orthodontic treatment compliance