Effect of Clear Aligner Attachment Size on Extrusion of Maxillary Lateral Incisors

June 5, 2026 updated by: Virginia Commonwealth University
Orthodontic treatment has been revolutionized by clear aligner therapy, offering patients a more esthetic and comfortable alternative to traditional braces. In 1999, Align Technology introduced Invisalign. As Invisalign has increased in popularity and demand over the past two decades, clinical trials have shed light on the efficacy of Invisalign treatment. there have been changes in the Invisalign protocol such as introduction of SmartForce features in 2008, such as optimized attachments as well as the implementation of SmartTrack aligner material in 2011. Compared to conventional fixed orthodontic appliances, Invisalign cannot be adjusted on a visit-to visit basis. If ideal tooth movement has not been achieved after completion of the first sequence of aligners, additional trays, known as refinement trays, are required.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

There are various expert theories regarding the most effective methods of extrusion and multiple studies performed in vitro to evaluate the efficacy of different attachment types on the extrusion of lateral incisors, however only one in vivo clinical trial exists. There is a need for more randomized clinical trials that evaluate the effectiveness of different attachment designs for achieving optimal extrusion of lateral incisors. By determining the most effective attachment size for maxillary lateral incisor extrusion, this study can help improve treatment outcomes for orthodontic treatment with clear aligners and serve as a guide to assist clinicians in selecting the most effective attachment design.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
28

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Steven Lindauer

Study Locations

  • United States
    • Virginia
      • Richmond, Virginia, United States, 23298
        • Virginia Commonwealth University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients treated with either Comprehensive Invisalign or Invisalign Teen treatment
  • The maxillary arch has less than 6 mm of crowding or spacing
  • Maxillary lateral incisors have a minimum of 0.3 mm of extrusion prescribed in the Tooth Movement Table on the Invisalign ClinCheck for the first set of aligners
  • Maxillary lateral incisors within a normal range of bucco-lingual inclination
  • Patients 12 years of age or older and either the patient or legal guardian are able to give consent
  • Patients confirm good compliance throughout the study period

Exclusion Criteria:

  • Patients do not complete all aligners in the first phase as prescribed
  • Poor compliance recorded for aligner wear
  • Restorations placed or oral surgery completed prior to final scan
  • Midcourse intervention to improve tracking such as a bootstrap
  • Maxillary lateral incisors not tracking and noted by minimum of 1 mm of aligner material incisally displaced when aligner fully seated
  • Treatment plans include surgery or extractions
  • Maxillary lateral incisors with pathology and restorations
  • Missing teeth other than third molars
  • Patients with anterior crossbite

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Control/optimized for extrusion.aligners
The control will be Invisalign's optimized attachment which will be specifically optimized for extrusion.
Device: Corresponding treatment order in the prescription with Align Technology
Treating orthodontist placing the corresponding order in the prescription with Align Technology.
Device: Superimposition of final and initial positions of lateral incisors: Predicted model
Superimposition of final and initial positions of lateral incisors, two superimpositions will be completed. The pretreatment model will be superimposed with the predicted final model to establish the predicted movement of the maxillary lateral incisors
Experimental: Gingivally beveled 1x1x3mm aligners
Each set of aligners would be worn for a week/gingivally beveled 1x1x3mm
Device: Corresponding treatment order in the prescription with Align Technology
Treating orthodontist placing the corresponding order in the prescription with Align Technology.
Device: Superimposition of final and initial positions of lateral incisors: Gingivally beveled 1x1x3mm aligners
Superimposition of final and initial positions of lateral incisors, two superimpositions will be completed. The pretreatment model (Gingivally beveled 1x1x3mm aligners) will be superimposed with the posttreatment model to establish the actual movement of the maxillary lateral incisor.
Experimental: Gingivally beveled 1x1x4mm aligners
Each set of aligners would be worn for a week/gingivally beveled 1x1x4mm
Device: Corresponding treatment order in the prescription with Align Technology
Treating orthodontist placing the corresponding order in the prescription with Align Technology.
Device: Superimposition of final and initial positions of lateral incisors: Gingivally beveled 1x1x4mm aligners
Superimposition of final and initial positions of lateral incisors, two superimpositions will be completed. The pretreatment model (Gingivally beveled 1x1x4mm aligners) will be superimposed with the posttreatment model to establish the actual movement of the maxillary lateral incisor.
Experimental: Gingivally beveled 1x1x5mm aligners
Each set of aligners would be worn for a week/gingivally beveled 1x1x5mm
Device: Corresponding treatment order in the prescription with Align Technology
Treating orthodontist placing the corresponding order in the prescription with Align Technology.
Device: Superimposition of final and initial positions of lateral incisors: Gingivally beveled 1x1x5mm aligners
Superimposition of final and initial positions of lateral incisors, two superimpositions will be completed. The pretreatment model (Gingivally beveled 1x1x5mm aligners) will be superimposed with the posttreatment model to establish the actual movement of the maxillary lateral incisor.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Determine which of three different attachment sizes offers more predictable extrusion of maxillary lateral incisors in subjects treated with clear aligners compared
Time Frame: baseline until the clear aligner treatment is completed at 20 to 25 weeks
The aim of this prospective, randomized controlled trial is to determine which of three different attachment sizes (gingivally beveled 1x1x3 mm, gingivally beveled 1x1x4 mm, or gingivally beveled 1x1x5 mm) offers more predictable extrusion of maxillary lateral incisors in patients treated with clear aligners compared to control.
baseline until the clear aligner treatment is completed at 20 to 25 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Evaluate the accuracy of ClinCheck software
Time Frame: baseline until the clear aligner treatment is completed at 20 to 25 weeks
To evaluate the accuracy of ClinCheck software in predicting the three-dimensional final position of the lateral incisor following extrusion using the attachment designs tested.
baseline until the clear aligner treatment is completed at 20 to 25 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Virginia Commonwealth University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Steven Lindauer, Virginia Commonwealth University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 31, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 3, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 3, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 7, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HM20031880

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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