Frequency and severity of malocclusions in patients with statutory health insurance in a German orthodontic practice in North Rhine Westphalia – a multi‑part cross‑sectional study over a 20‑year period

Abstract

Objective Since 2002, patients with statutory health insurance in Germany must undergo an assessment of orthodontic treatment need using the "Kieferorthopädische Indikationsguppen" (KIG; orthodontic indication groups) classifcation system. According to this system, tooth and jaw misalignment are divided into 11 subgroups and fve grades. The objectives of this study were to determine the distribution of KIG classifcations in patients with statutory insurance of a German orthodontic practice (North Rhine, Germany) and to analyze changes over a 20-year period. Materials and Methods Since the introduction of the KIG index in 2002, 4940 statutorily insured patients over a 20-year period (2330 m, 2610 f, min 3.2, max 49.5 years, peak between 10 and 12 years) were classifed at their frst appointment. According to the valid guidelines of the statutory health insurance (GKV), the division was made into the highest possible KIG classifcation. Multiple entries were thus not made. In accordance with the operating cycles of the practice, the progression was divided into four 5-year periods. Results Over a 20-year period, 24.98% of the patients were assigned to the classifcation "D". 86.52% of the patients were among the 6 most frequently ("D", "E", "K", "S", "P" and "M",>10% each) and only 13.49% among the 5 least frequently recorded classifcations ("U", "B", "T", "O" and "A",<5% each). Conclusion The distribution of the 6 most frequent and the 5 least frequent KIG classifcations was constant over a 20-yearperiod. Among all possible tooth and jaw misalignment variants, the sagittal classifcations "D" and "M" represent the most frequent malocclusions. Clinical relevance The results and their comparison with historical data show that both frequency and severity of tooth and jaw misalignment with orthodontic treatment need appear identical for patients with statutory health insurance over a 20-year period.