Direct vs Indirect In-House Clear Aligners vs Fixed Appliances in Orthodontic Treatment

July 4, 2026 updated by: Ahmet Yağcı, TC Erciyes University

Comparison Of Efficiency And Treatment Duration Between Clear Aligners Manufactured Directly And Indirectly By The Clinician And Fixed Orthodontic Treatment: An In Vivo Randomized Clinical Trial

Clear aligner therapy has become increasingly popular as an esthetic alternative to conventional braces in orthodontic treatment. While clear aligners are traditionally manufactured by commercial laboratories using a thermoforming technique, recent advances in 3D printing technology now allow clinicians to produce aligners directly in their own clinic, either by printing the aligner itself (direct method) or by printing a model and then thermoforming the aligner over it (indirect method)." "This study compares three approaches to orthodontic treatment in patients with mild to moderate dental crowding who do not require tooth extraction: clear aligners produced directly in-house using 3D printing with a shape-memory resin, clear aligners produced indirectly in-house using a 3D-printed model and thermoforming, and conventional fixed orthodontic treatment with metal brackets and wires." "A total of 36 patients aged 12 to 30 years were randomly assigned to one of these three treatment groups, and 33 patients completed the study. Treatment quality was evaluated using the American Board of Orthodontics Objective Grading System (ABO-OGS), an objective scoring method based on dental models obtained at the end of treatment. The total duration of treatment, from the start of active treatment to its completion, was also compared among the three groups." "The findings of this study may help clinicians and patients better understand the advantages and limitations of in-house clear aligner production compared to conventional fixed appliances, particularly regarding treatment efficiency and duration.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

36

Phase

  • 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 Locations

  • Turkey (Türkiye)
    • Melikgazi
      • Kayseri, Melikgazi, Turkey (Türkiye)
        • Erciyes University, Faculty of Dentistry, Department of Orthodontics

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

Description

Inclusion Criteria:

  • Presence of permanent dentition (no primary teeth remaining)
  • Non-extraction orthodontic treatment plan
  • Age between 12 and 30 years
  • Mild to moderate dental crowding (0-6 mm)
  • Skeletal Class I classification (ANB: 2±2°)
  • Normal vertical growth direction (Sn-GoGn: 32±6°)
  • No congenital tooth agenesis (excluding third molars)
  • No atypical tooth shapes
  • No extracted permanent teeth
  • No dental caries
  • Good oral hygiene
  • Healthy periodontal tissues

Exclusion Criteria:

  • Presence of craniofacial anomalies
  • Systemic disease or condition
  • Previous fixed orthodontic treatment
  • History of allergy to dental materials
  • History of xerostomia

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: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group A ( Direct - In-House)
Participants received clear aligners manufactured directly by the clinician using 3D printing with a shape-memory resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea).
Device: Direct In-House Clear Aligners
Clear aligners fabricated directly by the clinician using a stereolithography (SLA) 3D printer (Asiga MAX UV) with a shape-memory resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea). The shell of the aligner was designed digitally using Direct Aligner Designer software and printed directly, without the need for a physical model. Printed aligners were post-processed by centrifugation to remove excess resin, followed by UV light curing.
Experimental: Group B ( Indirect - In-House)
Participants received clear aligners manufactured indirectly by the clinician via 3D-printed models followed by thermoforming with CA Pro+ sheets (SCHEU-DENTAL GmbH, Iserlohn, Germany).
Device: Indirect In-House Clear Aligners
Clear aligners fabricated indirectly by the clinician via 3D-printed dental models (Asiga MAX UV printer) followed by thermoforming using CA Pro+ sheets (0.75 x 120 mm, SCHEU-DENTAL GmbH, Iserlohn, Germany) with a pressure-forming machine (MINISTAR S). The thermoformed aligners were trimmed from the printed model after shaping.
Active Comparator: Group C (Fixed Orthodontic Treatment)
Participants received conventional fixed orthodontic treatment with metal brackets (AO Mini Master Roth 018).
Device: Fixed Orthodontic Appliances
Conventional fixed orthodontic treatment using metal brackets (AO, Mini Master Roth 018, ) bonded to the upper and lower dental arches with stainless steel archwires.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Treatment Quality Assessed by the American Board of Orthodontics Objective Grading System (ABO-OGS)
Time Frame: From the date of treatment initiation (attachment placement or bracket bonding) until the date of treatment completion (final day of aligner use or bracket debonding), assessed up to 13 months
Post-treatment dental models were evaluated using the ABO Objective Grading System, which scores eight criteria: tooth alignment, marginal ridge height, buccolingual inclination, overjet, occlusal contacts, occlusal relationships, interproximal contacts, and root angulation. Lower total scores indicate better treatment quality. Scores were classified as successful (<20), borderline (20-30), or unsuccessful (>30).
From the date of treatment initiation (attachment placement or bracket bonding) until the date of treatment completion (final day of aligner use or bracket debonding), assessed up to 13 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total Treatment Duration
Time Frame: From the date of treatment initiation (attachment placement or bracket bonding) until the date of treatment completion (final day of aligner use or bracket debonding), assessed up to 13 months
The total duration of treatment was calculated as the time interval between treatment initiation (aligner delivery or bracket bonding) and treatment completion (final day of aligner use or bracket debonding)
From the date of treatment initiation (attachment placement or bracket bonding) until the date of treatment completion (final day of aligner use or bracket debonding), assessed up to 13 months

Collaborators and Investigators

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

Sponsor

TC Erciyes University

Collaborators

The Scientific and Technological Research Council of Turkey

Investigators

  • Principal Investigator: Ahmet Yağcı, Prof. Dr., Erciyes University, Faculty of Dentistry, Department of Orthodontics
  • Study Director: Musa Göksu, DDS, Erciyes University, Faculty of Dentistry, Department of Orthodontics

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)

February 15, 2024

Primary Completion (Actual)

March 15, 2025

Study Completion (Actual)

March 15, 2025

Study Registration Dates

First Submitted

June 28, 2026

First Submitted That Met QC Criteria

July 4, 2026

First Posted (Actual)

July 7, 2026

Study Record Updates

Last Update Posted (Actual)

July 7, 2026

Last Update Submitted That Met QC Criteria

July 4, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TDH-2024-14031

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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