Visual object database browsers are essentially based on two kinds of interactions: navigation within a collection of objects, and navigation between objects via their relationships. These two interactional operators have proven to adequately support the main user task addressed by these tools, i.e. exploring the states of a set of related objects. In temporal object databases, visual browsing tools should additionally support users tasks such as studying a snapshot of a collection of objects at a given instant, or detecting and examining changes within object states. In this paper, we show that the two interactional operators supported by classical object browsers do not adequately address these tasks. We consequently propose an interactional operator dedicated to navigation through time, and we study how it can be orthogonally integrated with the above two.