The risk of caries and periodontal disease in case of crowding and overjet has been analysed in an epidemiologic cross sectional study based on clinical findings and cast analysis. 125 patients were devided into different groups: the first group aged between 18 and 34 years, 31 male and 32 female; the second group aged 35 years and older, 31 male and 31 female. The clinical examination was based on the WHO-OHS methods. The modified analyses of segmented arch systems by LUNDSTRÖM was used to acquire the amout of crowding, the registration of the amout of overjet based on an analysis by KLINK-HECKMANN. The study figured out the correlations between age, the amount of crowding and overjet and caries, dental fractures, abrasion, gingivitis and periodontal disease. A high risk for dental destruction was found by patients with crowding of more than 5 mm and overjet of more than 5 mm. Keywords: crowding in the lower labial segment, overjet, caries, dental fracture, periodontal disease, bleeding, pocketing, recession, abrasion