M Beerens

SUMMARY 7 119 Chapter 3 Theuseof DenaturingGradient Gel Electrophoreses and conventional microbiology as indicator of white spot lesions in orthodontic patients; a cross-sectional study. Predicting caries risk in patients undergoing treatment with fixed appliances would be valuable with respect to WSL formation. Denaturing Gradient Gel Electrophoresis (DGGE) and microbial composition have been suggested to predict caries risk in young children. In the current study the predictive value of these two methods was assessed in patients with full fixed appliances. Dental plaque samples of patients with and without WSL were mutually compared. Dental plaque was obtained from 37 patients immediately prior to bracket removal. These samples were analysed with Gellcompare-II software applied on Denaturing Gradient Gel Electrophoresis (DGGE) patterns; the software was adjusted by varying the automated band detection settings and the findings were compared to visually detected bands to find optimum settings. Secondly, the plaque samples were analysed by a conventional microbiology plating method to assess numbers of total colony forming units (CFU’s), percentages of aciduric flora, Streptococcus mutans, Lactobacillus spp. and Candida albicans , respectively. The presence of WSL was determined immediately after bracket removal, which showed that 28 patients had WSL and only nine were WSL free. By changing software settings, the number of bands detectedwas altered. Band numbers identified for subjects with or without WSL were either significant or not significant depending on the settings of the software. No differences between groups were observed for the microbiological parameters (aciduric flora, S. mutans, Lactobacillus spp. and C. albicans ). We conclude that Gelcompar-II software settings significantly affect outcomes. DGGE and conventional microbiologial parameters for total colony forming units (CFU’s) and percentages of aciduric flora, S. mutans , Lactobacillus spp. and C. albicans cannot predict risk of the formation of WSL in these orthodontic patients.