Fig. 1From: Development of an Ontology for PeriodontitisA hierarchy of upper categories in our ontology for molecular pathology in periodontitis. This figure shows upper categories from the first to the seventh level of PeriO. It shows all the classes in the first, second, third, fourth, and fifth levels, while only representative classes are shown in the sixth and seventh levels. Edges in solid lines indicate ‘is_a’ relations. Edges in broken lines indicate ‘has_part’ relations. Classes in red were inherited from BFO. Classes in blue were inherited from OGMSBack to article page