Inflammation in Clear Aligners With and Without Attachments

March 26, 2026 updated by: Amy C. Killeen, University of Nebraska

Molar-Specific Inflammatory Biomarkers in Adolescents Using Clear Aligners With and Without Attachments

Problem: Clear aligner therapy is widely used in orthodontics due to improved periodontal outcomes compared to fixed appliances. However, composite attachments are frequently bonded to molars to enhance biomechanics, potentially creating plaque-retentive areas that may increase localized inflammatory responses. Currently, no studies have directly compared periodontal inflammatory biomarker levels in molars treated with clear aligners with versus without attachments. This gap limits understanding of the biological impact of attachments on periodontal tissues.Hypothesis:First molars treated with clear aligners and composite attachments will demonstrate higher levels of inflammatory biomarkers in gingival crevicular fluid (GCF) compared to molars treated with clear aligners without attachments. Biomarker levels are expected to be lower in the non-attachment group. Methods: This study will include 30 orthodontic patients divided into two groups (15 per group):1. Clear aligners with molar attachments 2. Clear aligners without molar attachments. GCF samples will be collected from first molars at a routine orthodontic appointment at the UNMC College of Dentistry Graduate Orthodontic Clinic. Primary biomarkers include IL-1β, IL-6, TNF-α, and MMP-8 measured via ELISA. Clinical periodontal parameters (Plaque Index, Gingival Index, Bleeding on Probing, Probing Depth) will also be recorded.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Detailed Study Protocol:

This pilot clinical study will recruit subject currently undergoing orthodontic therapy in the graduate orthodontic residency program at the UNMC College of Dentistry. Each subject will be screened for recruitment into the study by review of records by study personnel to determine qualifications regarding inclusion and exclusion criteria. Once the subject has been screened, the subject (if over 18 years old) or the subjects' parent (if subject is between 14-18 years old) will be introduced to the study and invited to participate. The consent form will be reviewed, all questions answered and informed consent obtained prior to data collection. Study groups will consist of 15 subjects per group. Group A will be comprised of 15 subjects undergoing clear aligner orthodontic therapy with bonded composite attachments on the first molars. Group B will be comprised of 15 subjects undergoing clear aligner therapy without attachments on the first molars. The decision whether or not to use aligners is not a study decision and is part of routine orthodontic treatment planning and care. Routine aligner protocol includes a 1 week change schedule (aligner trays are changed/switched weekly) and must be worn a minimum of 22 hours/day. At the single data collection appointment, data collection will include assessment of plaque presence/absence at the mesiobuccal site of the first molars, gingival crevicular fluid (GCF) collection at the mesiobuccal site of the first molars, Gingival Index (Loe & Silness) assessment at the mesiobuccal of each first molar (visual determination of gingival inflammation), probing depth assessment at the mesiobuccal of each first molar, and bleeding on probing (BOP) assessment at the mesiobuccal of the first molars. These measurements are being done for study purposes only.

The GCF collection procedure includes isolation of the tooth with cotton rolls, followed by gentle removal of all supragingival plaque with a dental explorer instrument. A small paper point will be inserted into the mesiobuccal gingival sulcus and held for 30 seconds to absorb the GCF. Four samples will be taken from each patient, one sample from each first molar. All samples will be stored at -80 degrees Celsius until assay.

Statistical analysis will be completed via t-tests and modeling. Within-patient differences will be calculated by subtracting the inflammatory marker value from a tooth without an attachment from a tooth with an attachment. These differences within patients will be averaged across all patients and compared to a null value of zero using a one sample t-test to see if the difference is statistically significant (this is the same as a paired t-test). This will be done for multiple inflammatory markers of interest, with IL1beta as the primary outcome of interest. As secondary, exploratory analyses, these difference scores will be compared to variables of interest (e.g., age, sex, length of time in a clear aligner, etc.), to see if there are associations with the size of differences observed, using Pearson or Spearman correlations for continuous variables, or Wilcoxon rank sum or Kruskal Wallis test

The primary outcome will be measure of inflammatory biomarker levels in GCF from first molars; specifically IL-1B. IL-6, TNF-alpha, MMP-8 will be measured as secondary outcomes. All biomarkers will be measured in pg/µL.

Additional outcomes will include assessment of periodontal clinical parameters (plaque presence, Gingival index, BOP, probing pocket depth (PD).

Study Type

Observational

Enrollment (Estimated)

30

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 Locations

  • United States
    • Nebraska
      • Lincoln, Nebraska, United States, 68358
        • University of Nebraska Medical Center College of Dentistry

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

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Study population will include clear aligner orthodontic patients at the UNMC College of Dentistry aged 14-25 years old.

Description

Inclusion Criteria:

  • orthodontic patient at the UNMC College of dentistry
  • clear aligner therapy

Exclusion Criteria:

  • pregnancy

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

Cohorts and Interventions

Group / Cohort
Attachments
Clear aligner with molar attachment users
No attachments
Clear aligners without molar attachment users

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
IL-1B
Time Frame: Day 1
Measure of IL-1B at molar sites
Day 1

Collaborators and Investigators

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

Sponsor

University of Nebraska

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

March 20, 2026

First Submitted That Met QC Criteria

March 26, 2026

First Posted (Actual)

April 2, 2026

Study Record Updates

Last Update Posted (Actual)

April 2, 2026

Last Update Submitted That Met QC Criteria

March 26, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0171-26-EP

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

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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