The Effect of Functional Appliances on the Skeletal Pattern

The findings of some 26 papers covering the results of Andresen and Fränkel appliances, as analysed from cephalometric radiographs, are reviewed. These findings show a high degree of consistency. They have been combined to produce larger samples, and compared with a control group produced from reports of untreated Class II division 1 individuals, with consequent gains in statistical significance. Generally, there is no appreciable holding back of maxillary advancement in either group (although a slight relative reduction in the angle SNA). There is a slight mean increase in mandibular growth, mainly in a vertical direction. This seems similar to that reported by several authors in conventional appliances. There is a wide variation in response.