Age-dependent prevalence of malocclusions requiring treatment according to the KIG classification

The distribution of KIG classifications requiring treatment was not homogeneous, but age dependent. The differences were particularly evident in the early treatment group and may be due to the limited applicability of the KIG classification system in patients before late mixed dentition. With increasing age at initial examination, the prevalence of sagittal classifications decreased, while that of vertical classifications increased. Still, the sagittal classifications D and M occurred most frequently in all age groups. The KIG classification D was always the most common in all patients until the age of 18.