The present study aimed to investigate the incidence and further course of White Spot Lesions (WSL) during and after multibrackets appliance (MB) treatment. All former MB-patients finishing orthodontic treatment at the University of Giessen between 1996 and 2006 were screened. The first 400 patients (168 male, 232 female) meeting the in-clusion criteria - all upper front teeth (UFT) fully erupted and visible on before treatment photographs, no fillings or structural abnormalities, duration MB treatment greater-than-or-equal 1 year, retention period greater-than-or-equal 1 year - were selected. The average age of the patients was 13.7 years (SD 3.5) and the average MB treatment time 1.9 years (SD 3.6). A modification of the White Spot Index by Gorelick et al. (1982) was used to evaluate the labial surface of the four front teeth in the upper incisor area on intra-oral photos before (T0), after treatment (T1) and after the end of retention (T2). The results revealed the following: Before treatment 32.3% of the patients exhibited WSL on 19.7% of the UFT. After MB treatment 73.5% of the patients and 57.4% of the UFT presented WSL. The incidence of WSL during MB treatment amounted to 60.9% of the patients. The majority of the UFT (41.2%) had mild lesions while the remaining UFT were af-fected severely with (3.8%) or without (12.4%) cavitations at T1. Only 26.5% of the patients were free of WSL both at T0 and at T1. After the retention phase the majority of the lesions (68.4%) were improved, 20.7% were unchanged and 10.9% had worsened. Male WSL-patients tended to show more severe WSL than females. There was a tendency for an increased WSL development during the adolescent com-pared to pre- and post-adolescent age groups. It was concluded, that using only general prophylactic measures, new WSL developing on the UFT during MB treatment remain to be a frequent undesired side-effect affecting 60.9% of the patients counteracting our efforts for clinical excellence.
