Why the pan in the patient groups described? Hans-Goran ------------------------------------------------------------- Professor Hans-Goran Grondahl Department of Oral and Maxillofacial Radiology Faculty of Odontology Goteborg University P O Box 450 SE 405 30 Goteborg, Sweden telephone: 46 31 7733166 telefax: 46 31 827351 e-mail: h-g.grondahl at odontologi.gu.se