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OpenTrials
Completed

NCT Number: NCT07687329

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

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.

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Key information

Age range

12 year–30 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Erciyes University, Faculty of Dentistry, Department of Orthodontics

Kayseri, Melikgazi, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Direct In-House Clear Aligners

Device

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.

Indirect In-House Clear Aligners

Device

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.

Fixed orthodontic appliances

Device

Conventional fixed orthodontic treatment using metal brackets (AO, Mini Master Roth 018, ) bonded to the upper and lower dental arches with stainless steel archwires.

Primary outcomes

  1. 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).

Secondary outcomes

  1. 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)

Sponsors and collaborators

Lead sponsor

TC Erciyes University

Other

Collaborators

  • The Scientific and Technological Research Council of Turkey

Registry information

Official study title

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

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Jul 7, 2026
Registry last updated
Jul 7, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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