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

NCT07687329 | Completed

• 1 other identifier: TDH-2024-14031
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Malocclusion, Angle Class I

Keywords

Clear aligners; Fixed orthodontic appliance; 3D Printing; In-House Aligners; Orthodontic Treatmen Duration; ABO Objective Grading System

Outcome Measures

Primary Outcomes (1)

• Treatment Quality Assessed by the American Board of Orthodontics Objective Grading System (ABO-OGS)

  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 Outcomes (1)

• Total Treatment Duration

  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

Study Arms (3)

Group A ( Direct - In-House)

EXPERIMENTAL

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

Group B ( Indirect - In-House)

EXPERIMENTAL

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

Group C (Fixed Orthodontic Treatment)

ACTIVE COMPARATOR

Participants received conventional fixed orthodontic treatment with metal brackets (AO Mini Master Roth 018).

Device: Fixed Orthodontic Appliances

Interventions

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.

Group A ( Direct - In-House)

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.

Group B ( Indirect - In-House)

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.

Group C (Fixed Orthodontic Treatment)

Eligibility Criteria

• Age: 12 Years - 30 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

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

Sponsors & Collaborators

• TC Erciyes University: lead
• The Scientific and Technological Research Council of Turkey: collaborator

Study Sites (1)

Erciyes University, Faculty of Dentistry, Department of Orthodontics

Kayseri, Melikgazi, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Malocclusion, Angle Class I

Interventions

Orthodontic Appliances, Fixed

Condition Hierarchy (Ancestors)

Malocclusion; Tooth Diseases; Stomatognathic Diseases

Intervention Hierarchy (Ancestors)

Orthodontic Appliances; Orthodontics; Dentistry

Study Officials

• Ahmet Yağcı, Prof. Dr.

  Erciyes University, Faculty of Dentistry, Department of Orthodontics

  PRINCIPAL INVESTIGATOR

• Musa Göksu, DDS

  Erciyes University, Faculty of Dentistry, Department of Orthodontics

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PROF. DR.

Model Details: Participants were randomly assigned to one of three parallel groups: direct in-house clear aligners, indirect in-house clear aligners, or fixed orthodontic treatment.

Study Record Dates

• First Submitted: June 28, 2026
• First Posted: July 7, 2026
• Study Start: February 15, 2024
• Primary Completion: March 15, 2025
• Study Completion: March 15, 2025
• Last Updated: July 7, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)