Split-Mouth Comparison of Invisalign Attachments

NCT07215598 | Enrolling By Invitation FDA Device

• 1 other identifier: HP-00115664
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This study evaluates how accurately the attachments used in Invisalign treatment (Align Technology Inc., San Jose, CA, USA) match their planned shapes and sizes in the ClinCheck software (ClinCheck®, Align Technology Inc., San Jose, CA, USA). Attachments are small tooth-colored bumps that help clear aligners grip the teeth and move them effectively. The investigators are comparing two types of attachments: optimized and conventional, to determine which is bonded to the tooth more accurately and maintains its shape better over time. Participants beginning Invisalign treatment will have attachments placed as part of their normal care. Digital scans will be taken immediately after placement and during follow-up visits to assess attachment accuracy and wear. The goal is to identify which attachment design provides greater precision and durability to improve the predictability and efficiency of Invisalign treatment planning.

Conditions

Wear, Restoration; Volume Assessment; Clear Aligner Appliance

Keywords

volume assessment; invisalign; clear aligner; digital orthodontics; attachment wear

Outcome Measures

Primary Outcomes (3)

• Attachment Volume Accuracy

  Quantitative comparison of planned versus bonded Invisalign attachment volumes measured using 3D (three dimensional) digital scans. Each bonded attachment will be segmented from intraoral STL (Standard Tessellation Language) files and superimposed onto the corresponding planned ClinCheck model. The absolute difference in attachment volume (in mm³) between planned and bonded models will be calculated to assess bonding accuracy for optimized and conventional designs.

  1 month

• Attachment Active Surface Area Accuracy

  Quantitative difference in attachment active surface area using intraoral 3D scans. STL models obtained at baseline (immediately after bonding) and at 1 month will be superimposed to calculate difference in active surface area (mm²). The mean difference between planned and bonded surface areas will be compared for optimized and conventional attachment designs to evaluate bonding precision.

  1 month

• Positional Accuracy

  Difference between planned and bonded attachment position, measured as centroid displacement (mm) after 3D registration of STL models at baseline and 1 month.

  1 month

Secondary Outcomes (4)

• Volume Reduction Over Time

  6 months

• Volume Loss (Percentage)

  6 months

• Active Surface Area Change Over Time

  6 months

• Active Surface Area Change (Percentage)

  6 months

Study Arms (2)

Optimized

ACTIVE COMPARATOR

Optimized attachments are small, tooth-colored composite bumps placed on teeth during Invisalign treatment to help aligners deliver controlled forces for tooth movement. These attachments are digitally designed in the ClinCheck software to optimize force direction and retention. In this arm, optimized attachments will be bonded according to the manufacturer's standard template and curing protocols. Their bonded geometry and wear over time will be compared to those of conventional attachments placed on the contralateral teeth.

Device: Composite Aligner Attachment

Conventional

ACTIVE COMPARATOR

Conventional attachments are tooth-colored composite bumps placed on teeth during Invisalign treatment to improve aligner retention and control tooth movement. These attachments are designed with standard rectangular or ellipsoid shapes, following established clinical templates. In this arm, conventional attachments will be bonded using manufacturer-recommended materials and curing protocols. Their placement accuracy and wear characteristics will be compared to those of optimized attachments placed on the contralateral teeth within the same participant.

Device: Composite Aligner Attachment

Interventions

Composite Aligner Attachment DEVICE

Composite aligner attachments are small, tooth-colored resin bumps bonded to specific teeth during Invisalign treatment to enhance aligner retention and force application. These attachments are digitally planned in ClinCheck software and fabricated using manufacturer-provided templates. In this study, two designs: optimized and conventional, will be compared for their accuracy and durability using 3D digital scans at multiple time points.

Conventional; Optimized

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged18 years or older.
• Patients initiating Invisalign treatment with planned composite attachments.
• Ability to provide written informed consent and agree to additional research intra-oral scans.
• Good oral hygiene and absence of active periodontal disease at enrollment.

You may not qualify if:

• Extensive dental restorations (composites, crowns, veneers) on study teeth that could interfere with attachment bonding.
• Enamel defects or severe wear on study tooth surfaces affecting bonding accuracy.
• Contraindications to digital intraoral scanning (e.g., severe gag reflex, metallic prostheses preventing accurate imaging).
• Severe tooth malposition that would compromise accurate attachment placement.
• Poor oral hygiene or active periodontal disease at enrollment and/or if the patient develops poor oral hygiene or active periodontal disease during treatment.

Sponsors & Collaborators

• University of Maryland, Baltimore: lead

Study Sites (1)

University of Maryland School of Dentistry

Baltimore, Maryland, 21201, United States

Location

Related Publications (4)

• Muthuswamy Pandian S, Subramanian AK, Vaiid N. Comparison of efficacy and accuracy of tooth movements in optimized and conventional attachments of clear aligners - A systematic review and meta-analysis. J Oral Biol Craniofac Res. 2025 Sep-Oct;15(5):1123-1133. doi: 10.1016/j.jobcr.2025.07.019. Epub 2025 Jul 29.

  PMID: 40778386 BACKGROUND

• Li Q, Yang K. Surface wear of attachments in patients during clear aligner therapy: a prospective clinical study. Prog Orthod. 2024 Feb 19;25(1):7. doi: 10.1186/s40510-023-00506-y.

  PMID: 38369617 BACKGROUND

• Fausto da Veiga Jardim A, Curado de Freitas J, Estrela C. Surface wear and adhesive failure of resin attachments used in clear aligner orthodontic treatment. J Orofac Orthop. 2024 May;85(Suppl 1):52-62. doi: 10.1007/s00056-023-00471-5. Epub 2023 Jun 14.

  PMID: 37314488 BACKGROUND

• Bellocchio AM, Portelli M, Ciraolo L, Ciancio E, Militi A, Peditto M, Barbera S, Nucera R. Evaluation of the Clinical Variables Affecting Attachment Reproduction Accuracy during Clear Aligner Therapy. Materials (Basel). 2023 Oct 23;16(20):6811. doi: 10.3390/ma16206811.

  PMID: 37895792 BACKGROUND

Related Links

• Invisalign Attachments explanation

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Clinical Assistant Professor

Model Details: This is a prospective, randomized split-mouth (crossover) study evaluating two types of Invisalign attachments: optimized and conventional. Each participant receives both attachment types on contralateral teeth, allowing within-subject comparison of placement accuracy and wear under identical clinical conditions.

Study Record Dates

• First Submitted: October 7, 2025
• First Posted: October 10, 2025
• Study Start: November 20, 2025
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): July 1, 2028
• Last Updated: February 10, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: November 2025-July 2028
• Access Criteria: De-identified individual participant data (IPD) and supporting documents will be available to qualified researchers upon reasonable request to the Principal Investigator, following approval under the University of Maryland data governance policy.

Locations

US (1)