1. 'Department of Cariology/Endodontology/Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), Louwesweg 1, NL-1066 EA Amsterdam, The Netherlands,
2. Department of Electron Microscopy, AMC, University of Amsterdam, The Netherlands
3. 'Department of Cariology/Endodontology/Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), Louwesweg 1, NL-1066 EA Amsterdam, The Netherlands