(A retrospective case control study to validate the association between Interleukin-1 gene variations and adult chronic periodontal disease in European Caucasians)

Inclusion Criteria:

• Ethnicity: Dutch or German Caucasian

Exclusion Criteria:

• None (however, diabetics were excluded during original patient recruitment at several clinical sites).

All study subjects will be selected from pre-existing patient databases in Germany and the Netherlands. All chronic periodontitis cases and controls will be subjects who were at least 35 years old at time of enrollment. Classification of chronic periodontitis will be based on extent of alveolar bone loss with consideration of tooth loss.