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RecruitingNCT05993156Updated Aug 15, 2023

Effects of Modified Fixed Twin Block Versus Removable Twin Block on Skeletal Class 2 Growing Patients With Mandibular Deficiency

An interventional study of modified Fixed twinblock and removable twin block in Malocclusion, Angle Class II and Mandible Small, sponsored by Cairo University. Recruiting at 1 site in Egypt. Open to female participants aged 9 Years to 15 Years. Per ClinicalTrials.gov, last updated 2023-08-15.

Primary conditionMalocclusion, Angle Class IIRegistry: MalocclusionReclassifiedWhy we changed it
Registry
Malocclusion — the first condition term the registry derived for this study.
ClinicalTrials.gg
Malocclusion, Angle Class II
Why
  1. The study's listed conditions name Malocclusion, Angle Class II, a narrower term within Malocclusion.
Confidence
High: the new condition is named in the study's own listed conditions. Of 351 hand-checked studies reclassified this way, 68% were exactly right and 84% in the right disease family; the registry's first term was right for 5% (measured 2026-10-21). How we classify →
Wrong?
Tell us the study's main condition →

Sponsored by Cairo University · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Primary completion was expected by Oct 2023, 3 years ago, but the record still lists the study as recruiting.
  • Registered 7 months after the study started (first participant enrolled Dec 2022, registered Jul 2023).
  • Started Dec 2022; still recruiting 3 years 11 months later.
Phase
Not applicable
Study type
Interventional
Enrollment
24
Allocation
Randomized
Ages
9 Years to 15 Years
Sex
Female
01

Study summary

Effects of modified fixed twin block versus removable twin block on skeletal class 2 growing patients with mandibular deficiency:

A Randomized Clinical Trial

Read the detailed description

The main objective of the study is to evaluate the effects of the modified fixed TB on class 2 growing cases and to compare its effect to the conventional removable TB

Research question Does the modified fixed twin block have the same effects as removable twin block during treatment of skeletal class 2 growing patients with mandibular deficiency?

PICO P: Growing skeletal class 2 patients with deficient mandible I : Modified Fixed Twin block C: Conventional removable Twin block

O :

Primary outcome:

Overjet

Secondary outcome:

Soft tissue Profile Antro-posterior mandibular position Mandibular length Antro-posterior maxillary position Upper and lower Incisors inclinations Durability of the appliance Patient Acceptance

Hypothesis:

There is no difference between the modified fixed or removable Twin block appliance regarding overjet reduction, dentoskeletal effects and patient perception.

  1. Trial design: Randomized Clinical Trial Parallel group, two arm, equivalent trial with 1:1 allocation ratio.
02

Conditions studied

  • Malocclusion
  • Angle Class II
  • Mandible Small

Browse trials for

Keywords

  • orthodontics
  • orthopedics
  • myofunctional appliance
  • Twinblock
03

In context

Malocclusion, Angle Class II Reclassified

124 studies on the registry are indexed under Malocclusion, Angle Class II; 19 are open to participants now.

This study's planned enrollment of 24 is below the median of 34 across 115 interventional studies indexed under Malocclusion, Angle Class II.

Browse Malocclusion, Angle Class II studies →

Lead sponsor

Cairo University is the lead sponsor of 4,941 studies on the registry; 1,458 are open to participants now.

Of its 37 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.

Browse Cairo University studies →

Compared within Malocclusion, Angle Class II, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Malocclusion. The counts are of registry records indexed under each term, refreshed daily. How we classify →

04

Who can participate

Ages eligible
9 Years to 15 Years
Sexes eligible
Female
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Skeletal Class 2 malocclusion cases (ANB ≥ 5 degrees)
  • Overjet ≥ 5 mm
  • Growing patients (CVMS 3 or 4)

Exclusion criteria

Exclusion Criteria:

  • Skeletally mature patients 15 years old or above
  • Patients with normal mandible and only protruded upper incisors.
  • Syndromic, cleft patients and patients with dental anomalies
  • Previous orthopaedic or orthodontic treatment
  • No sex predilection.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
24 participants (estimated)

Study arms

  • Active comparator
    Removable twin block group

    participants would receive conventional removable twin block for correction of class II malocclusion for 9 months

    Device: removable twin block

  • Experimental
    Fixed twin block group

    participants would receive a modified fixed twin block for correction of class II malocclusion for 9 months

    Device: modified Fixed twinblock

Interventions

  • Devicemodified Fixed twinblock

    modified fixed twin block functional appliance, with cemented bands on the first molars

    Also known as: F.T.B.

  • Deviceremovable twin block

    Conventional Removable Clark twin block myofunctional appliance

    Also known as: R.T.B.

06

What researchers measure

Primary outcomes

  1. Over jet reduction

    the horizontal distance between upper and lower incisors

    Time frame: 9 months

Secondary outcomes

  1. Effective mandibular length

    distance from condylon to the Pogonion points

    Time frame: 9 months

  2. lower incisor inclination

    inclination of lower incisors on the mandibular plane

    Time frame: 9 months

07

Study locations

1 of 1 sites recruiting
08

References and documents

Publications

  • Alhammadi MS, Halboub E, Fayed MS, Labib A, El-Saaidi C. Global distribution of malocclusion traits: A systematic review. Dental Press J Orthod. 2018 Nov-Dec;23(6):40.e1-40.e10. doi: 10.1590/2177-6709.23.6.40.e1-10.onl. Erratum In: Dental Press J Orthod. 2019 Aug 01;24(3):113. doi: 10.1590/2177-6709.24.3.113.err. PubMed 30672991 ↗
  • Burhan AS, Nawaya FR. Dentoskeletal effects of the Bite-Jumping Appliance and the Twin-Block Appliance in the treatment of skeletal Class II malocclusion: a randomized controlled trial. Eur J Orthod. 2015 Jun;37(3):330-7. doi: 10.1093/ejo/cju052. Epub 2014 Oct 8. PubMed 25296729 ↗
  • Caldwell S, Cook P. Predicting the outcome of twin block functional appliance treatment: a prospective study. Eur J Orthod. 1999 Oct;21(5):533-9. doi: 10.1093/ejo/21.5.533. PubMed 10565094 ↗
  • Clark William J., Mahony Derek, 2018. heal talk A journal of clinical dentistry 11.
  • Clark WJ. The twin block technique. A functional orthopedic appliance system. Am J Orthod Dentofacial Orthop. 1988 Jan;93(1):1-18. doi: 10.1016/0889-5406(88)90188-6. No abstract available. PubMed 3422118 ↗
  • Cozza P, Baccetti T, Franchi L, De Toffol L, McNamara JA Jr. Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review. Am J Orthod Dentofacial Orthop. 2006 May;129(5):599.e1-12; discussion e1-6. doi: 10.1016/j.ajodo.2005.11.010. PubMed 16679196 ↗
  • Ehsani S, Nebbe B, Normando D, Lagravere MO, Flores-Mir C. Short-term treatment effects produced by the Twin-block appliance: a systematic review and meta-analysis. Eur J Orthod. 2015 Apr;37(2):170-6. doi: 10.1093/ejo/cju030. Epub 2014 Jul 22. PubMed 25052373 ↗
  • Elfeky HY, Fayed MS, Alhammadi MS, Soliman SAZ, El Boghdadi DM. Three-dimensional skeletal, dentoalveolar and temporomandibular joint changes produced by Twin Block functional appliance. J Orofac Orthop. 2018 Jul;79(4):245-258. doi: 10.1007/s00056-018-0137-1. Epub 2018 Apr 16. PubMed 29663034 ↗
  • Linjawi AI, Abbassy MA. Dentoskeletal effects of the forsus fatigue resistance device in the treatment of class II malocclusion: A systematic review and meta-analysis. J Orthod Sci. 2018 Feb 15;7:5. doi: 10.4103/jos.JOS_80_17. eCollection 2018. PubMed 29765917 ↗
  • Matthaios S, Tsolakis AI, Haidich AB, Galanis I, Tsolakis IA. Dental and Skeletal Effects of Herbst Appliance, Forsus Fatigue Resistance Device, and Class II Elastics-A Systematic Review and Meta-Analysis. J Clin Med. 2022 Nov 26;11(23):6995. doi: 10.3390/jcm11236995. PubMed 36498570 ↗
  • O'Brien K, Wright J, Conboy F, Sanjie Y, Mandall N, Chadwick S, Connolly I, Cook P, Birnie D, Hammond M, Harradine N, Lewis D, McDade C, Mitchell L, Murray A, O'Neill J, Read M, Robinson S, Roberts-Harry D, Sandler J, Shaw I. Effectiveness of early orthodontic treatment with the Twin-block appliance: a multicenter, randomized, controlled trial. Part 1: Dental and skeletal effects. Am J Orthod Dentofacial Orthop. 2003 Sep;124(3):234-43; quiz 339. doi: 10.1016/S0889540603003524. PubMed 12970656 ↗
  • Thiruvenkatachari B, Harrison JE, Worthington HV, O'Brien KD. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children. Cochrane Database Syst Rev. 2013 Nov 13;(11):CD003452. doi: 10.1002/14651858.CD003452.pub3. PubMed 24226169 ↗

Individual participant data

Plan to share: No — results and statistical data would be published and IPD would be available upon request

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Dec 2022 (actual). Primary completion is estimated for Oct 2023, 10 months after the start.

Of 86 non-industry interventional studies with no phase under Malocclusion, Angle Class II, half reached primary completion within 15 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 22. This study's planned 10 months is below that.

Counting every sponsor, half of 86 studies reached it within 15 months; a quarter within 11 and three quarters within 22.

How these figures are worked out, and which studies are left out of them.

Registered
Jul 6, 2023
First posted
Aug 15, 2023
StartActual
Dec 1, 2022
Primary completionEst.
Oct 30, 2023
CompletionEst.
Oct 30, 2023
Last update
Aug 15, 2023
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Aug 15, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05993156
Lead sponsor
Cairo University
Responsible party
Omar yousry mahmoud mostafa (primary investigator, assistant lecturer, Cairo University) — Principal investigator
First posted
Aug 15, 2023
Start date
Dec 1, 2022
Primary completion
Oct 30, 2023 (estimated)
Completion
Oct 30, 2023 (estimated)
Last update
Aug 15, 2023

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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