The ADA Centre for Evidence-Based Dentistry has published a critical summary of a systematic review published earlier this year  (see Dental Elf 20-07-11)

The commentator noted that although the review was conducted thoroughly  only 4 studies were included two with a low risk of bias one with a high risk and the other an unclear risk. This together with  heterogeneity in the baselines , interventions and outcomes  means that the evidence to address the main question  of assessing the short term effectiveness of function appliances on  mandibular growth was limited.

Go to the ADA critical summary

Go to the PubMed abstract of the original review