The Signal Tandmobiel study is a dental study involving about 5000 schoolchildren in Flanders. They are annually examined by calibrated dentists from the 1st till the 6th class in primary school. A yearly questionnaire collects information on dietary as well as tooth brushing information. The longitudinal character of the data adds another dimension to the hierarchical structure. In the first part of the lecture the study will be described.
Dentists believe that there are spatial symmetries in the mouth with respect to caries.
However, this has never been shown in a statistical sense. In the second part of the talk this question is treated for primary teeth using data from the Signal Tandmobiel study. Our analyses confirm the dentist viewpoint.