Treatment of class III malocclusions frequently involves the use of functional appliances. The Fränkel regulator type III (FR-3) is a wire and acrylic appliance developed to treat class III malocclusions but there is controversy over its effectiveness. The aim of this review was to evaluate the effectiveness of the FR-3 in patients with Class III malocclusion in the growth and development period compared with untreated patients.
Searches were conducted in Medline, Cochrane Central Register of Controlled Trials,Embase, Scirus, Lilacs, Scopus, World Health Organization International Clinical Trials Registry Platform, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, and VIP Database for Chinese Technical Periodicals. 19 Chinese dental journals were hand searched. Randomised controlled trials (RCTs) clinical controlled trials(CCTs), and cohort studies (CS) were considered. To reviewers independently carried out study selection, data abstraction and risk of bias assessment. Study quality was assessed using the Newcastle-Ottawa Scale.
- 7 studies were included with 6 contributing to the meta-analysis.
- All 7 studies were cohort studies involving a total of 339 patients (182 treated; 157 controls)
- The meta-analysis showed:
- SNA changes did not differ in the short (mean difference, 0.43°; 95% CI, -0.52° to 1.39°) and long (mean difference, 0.37° ; 95% CI, -0.29° to 1.03°) terms.
- SNB changes significantly differed in the short (mean difference, -1.62°; 95% CI, -2.62° to -0.62°) and long (mean difference, -1.50°; 95% CI, -2.12° to -0.88°) terms.
- MPA changes did not differ in the short term (mean difference, 0.55°; 95% CI, -0.74°to 1.84°).
The authors concluded
This systematic review and meta-analysis shows that the evidence supporting the forward movement of the maxilla caused by the FR-3 appliance is not strong enough. Conversely, the theory that the FR-3 appliance restricts mandibular development seems reasonable; however, further high-quality studies are needed to arrive at a stable conclusion on the effectiveness of the FR-3 appliance on Angle Class III malocclusions.
A Cochrane review (Watkinson et al 2013) has looked at orthodontic treatment for class III malocclusion. That review only considered RCTs and there were none that addressed the use of the FR-3 which this new review confirms. The Cochrane review found some evidence to support the use of facemask appliances for treating class III maloclousions. However ,the only angle measurements in all the studies in the Cochrane review was ANB, which is not presented in this current review, so comparisons are difficult. While this review does suggest improvement in SNB in the short and medium term only a small number of Cohort studies are available and these are more prone to bias. This new review in common with the Cochrane review calls for agreement of which common outcomes should be reported to more easily compare different studies. The Cochrane review does suggests some options and it would be good to see orthodontic researchers agreeing a common way forward.
Yang X, Li C, Bai D, Su N, Chen T, Xu Y, Han X. Treatment effectiveness of Fränkel function regulator on the Class III malocclusion: A systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2014 Aug;146(2):143-154.
Watkinson S, Harrison JE, Furness S, Worthington HV. Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children. Cochrane Database of Systematic Reviews 2013, Issue 9. Art. No.: CD003451. DOI: 10.1002/14651858.CD003451.pub2.