Prevalence Of Erosion Based Lesions In German Recruits C. Ganss*, J. Klimek And T. Assmann (Dental Clinic, Justus-Liebig-University, Giessen, Germany) Since dental caries is declining, not-plaque-associated defects and erosion based lesions (EBL) in particular seem to gain in importance for oral health. However, prevalence studies on EBL are few in number and in most cases only cover small groups of subjects with a potential risk for EBL or are case reports. Data evaluating randomly selected young adults have not yet been published in Germany.   In this study 362 male subjects (mean age 20.8Ò1.6 yr) were randomly selected during the dental check-up at the beginning of their military service. Examinations were performed clinically by the same examiner under excellent illumination and careful air drying. EBL were assessed according to Lussi et al. (1991) and an erosion index (EI) as percentage of eroded surfaces of surfaces at risk was determined for each subject (Ganss et al., 1999). Additionally, a nutrition and health questionnaire was answered and sociodemographic data were obtained.   Twenty-three per cent of the participants had at least on tooth with an EBL grade 1 (affecting enamel only) and 4% with grade 2 (dentine involved). The mean erosion index was 0.84 (max. 16.7). Occlusal surfaces were the most affected followed by vestibular and oral surfaces:     occlusal (%) vestibular (%) oral (%) grade 1 (enamel lesions) 19.1 8.3 0.6 grade 2 (dentine affected) 3.9 0.3 0   EBL most often occurred in right and left first lower molars.   Most of the participants indicated a normal nutrition, only 2.8% lived on a vegetarian or raw food diet. In the case of EBL grade 2 a significant association to the intake of acidic food could be found (pÛ0.05), however, this was not true for EBL grade 1.   The results indicate that erosion based lesions could be found even at early age. Although they do not represent a serious problem in the present, their implication for dental health in the future should be paid attention for.