The effects of the Fränkel's function regulator on the Class III malocclusion.

The material of this investigation consisted of 40 functional Class III malocclusion subjects. Each treatment and control group consisted of 20 Class III cases (10 boys and 10 girls). The mean age of the subjects in the function regulator, FR-3, group was 9.5 years at the beginning of the treatment, and in the control group 9.3 years at the beginning of the observation period. The mean treatment period of the FR-3 group was 1.9 years and the mean observation period of the control group is 1.8 years. In this study, as a result of FR-3 appliance therapy in the functional Class III malocclusion group, the negative overjet that was present at the beginning of the treatment has been converted into a positive overjet by an average increase of 3.8 mm at the end of the treatment. The sum of downward and backward rotation of the mandible, the decrease in the SNB angle with a subsequent increase of the ANB angle, and the retrusion of the lower incisors were effective in the increase of the overjet. The increase in the SNA angle and the protrusion of the upper incisors were found to be insignificant. The overbite decreased due largely to the downward and backward rotation of the mandible.