Functional orthodontic appliances: effective in short-term suggests review


Class II malocclusion is one of the commonest orthodontic problems with around 25% of 12-year-old children in the UK being affected. However, differences in prevalence in some races and population groups exits. The aim of this review was to evaluate the effectiveness of removable functional appliances (RFAs) in the treatment of Class II malocclusion.


Searches were undertaken in 18 electronic databases (no details in main paper) without restriction on publication year or language. Only randomised controlled trials (RCTs) and prospective controlled clinical trials (CCTs) were considered. Two reviewers independently extracted data and risk of bias of included RCTs was assessed with the Cochrane Collaboration’s risk of bias tool. A separate checklist was used for CCTs. The overall quality of evidences was assessed using GRADE. Data were summaries using mean differences (MDs) and their corresponding 95% confidence intervals (CIs), with meta-analysis being conducted using a random-effects model.


  • 17 studies involving a total of 1031 patients reported in 19 papers were included.
  • There were 10 CCTs and 7 RCTs
  • 5 of the 7 RCTs were considered to be at high risk of bias, 1 at unclear risk and 1 at low risk.
  • Compared to untreated Class II patients Treatment was associated with
    • minimal reduction of SNA angle (11 studies, MD = -0.28 degree/year, 95% CI: -0.44 to -0.12 degree/year),
    • minimal increase of SNB angle (11 studies, MD = 0.62 degree/year, 95% CI: 0.36-0.88 degree/year), and
    • small decrease of ANB angle (10 studies, MD = -1.14 degree/year, 95% CI: -1.52 to -0.77 degree/year).
  • RFAs caused significant dentoalveolar changes (predominantly retroclination of the upper incisors) and significant soft tissue changes.
  • Skeletal changes were more pronounced with the Twin Block appliance.
  • Various patient- or appliance-related factors influenced the results of the subgroup analyses, while the sensitivity analyses indicated robustness.
  • Existing evidence was inadequate to assess the long-term effectiveness of RFAs.


The authors concluded

The short-term evidence indicates that RFAs are effective in improving Class II malocclusion, although their effects are mainly dentoalveolar, rather than skeletal.


This review has focused on RFAs for treating class II malocclusions and does demonstrate some benefit. A 2013 Cochrane review by Thiruvenkatachari et al (Dental Elf 7th Jan 2014) took a broader view and compare early treatment of Class II malocclusions with late treatment. The Cochrane review included 17 studies and concluded that:-

providing early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course of orthodontic treatment when the child is in early adolescence. There appears to be no other advantages for providing treatment early when compared to treatment in adolescence.

When looking in detail at this new review by Koretsi et al it is worth noting that a number of supplementary tables and figures are available on line and viewing this would be helpful in assessing this paper.


Koretsi V, Zymperdikas VF, Papageorgiou SN, Papadopoulos MA. Treatment effects of removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis. Eur J Orthod. 2014 Nov 13. pii: cju071. [Epub ahead of print] Review. PubMed PMID: 25398303.

Thiruvenkatachari B, Harrison JE, Worthington HV, O’Brien KD. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children. Cochrane Database of Systematic Reviews 2013, Issue 11. Art. No.: CD003452. DOI: 10.1002/14651858.CD003452.pub3.

Dental Elf – 7th Jan 2014 – Early orthodontic treatment may reduce incisal trauma in children with class II malocclusions

Dental Elf – 10th Oct 2014 – Fixed functional appliances for treatment of skeletal class II malocclusion

Dental Elf – Jul 29th 2012 – Review suggests twin-block appliance produces changes- but are they clinically important?

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