if ( registries != null )
{
ObjectClassRegistry objectClassRegistry = registries.getObjectClassRegistry();
// Unregister this ObjectClass into the Descendant map
objectClassRegistry.unregisterDescendants( objectClass, objectClass.getSuperiors() );
/**
* Remove the OC references (using and usedBy) :
* OC -> AT (for MAY and MUST)
* OC -> OC