Conventional versus 3D-printed twin block appliances: bacteria, surface texture, and effectiveness

Microbial Adherence, Surface Roughness, Effectiveness and Impact on Patients Between Conventional and 3D Printed Twin Block Appliances: An Open-Label Prospective Clinical Trial

NA · University of Malaya · NCT06944860

This trial will test whether 3D-printed twin block appliances work as well as conventional ones and whether they attract more bacteria or have rougher surfaces in growing children with Class II Division 1 malocclusion.

Quick facts

PhaseNA
Study typeInterventional
Enrollment32 (estimated)
Ages10 Years to 14 Years
SexAll
SponsorUniversity of Malaya (other)
Locations1 site (Kuala Lumpur, Kuala Lumpur)
Trial IDNCT06944860 on ClinicalTrials.gov

What this trial studies

Children who meet the age and dental criteria will receive either a conventional acrylic twin block or a 3D-printed twin block appliance. The study will compare microbial adherence (including bacterial and fungal load), measure material surface roughness, and track clinical outcomes such as overjet reduction and oral-health–related quality of life. Appliance surfaces will be sampled and analyzed microbiologically and examined for roughness while clinicians record complications, treatment failures, and patient acceptability. Findings will indicate whether 3D-printed materials perform similarly to conventional PMMA for twin block therapy.

Who should consider this trial

Good fit: Children with Class II Division 1 incisor relationship, overjet ≥ 7 mm, all permanent incisors and molars erupted, aged about 10–12 years for girls and 12–14 years for boys, and able to understand English or Bahasa Melayu.

Not a fit: Patients with craniofacial syndromes, previous orthodontic treatment, hyperdivergent facial type, untreated gingival disease, or those outside the specified age/eruption criteria are unlikely to benefit or qualify.

Why it matters

Potential benefit: If successful, this could identify a 3D-printed option that is as effective as conventional appliances but with similar or lower bacterial buildup and good patient acceptance.

How similar studies have performed: Some studies on other 3D-printed orthodontic materials have reported different surface roughness and increased microbial adhesion compared with PMMA, but direct evidence specific to twin block appliances is limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Patients with Class II Division 1 incisor relationship
2. Overjet of ≥ 7mm
3. Age range of children: 10-12 years in females, 12-14 years in males
4. All permanent incisors and molars erupted
5. ICDAS ≥ score 3 and BPE ≥ 3
6. Able to understand English or Bahasa Melayu

Exclusion Criteria:

1. Patients with craniofacial syndromes (example: cleft lip and palate)
2. Patients with previous history of orthodontic treatment
3. Patients with hyperdivergent facial type (MMPA \> 40º)
4. Untreated gingival disease (e.g.: gingivitis, periodontitis)

Where this trial is running

Kuala Lumpur, Kuala Lumpur

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Orthodontic Appliances, Removable, Orthodontic Appliance Complication, Class II Malocclusion, Division 1, Twin block appliance, Microbial adherence, Surface roughness, Effectiveness, Oral Health Related Quality of Life

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.