The identification of the pulp chamber roof and the pulp chamber floor is a more specialized issue in oral anatomy, and can be thought of as a house, with the pulp chamber roof being the roof of the house and the pulp chamber floor being the floor of the house, but this is relatively abstract. It should be clear that there is no pulp chamber floor in anterior teeth, because in addition to the pulp chamber roof, the root canal and apical foramen are further down in anterior teeth, while both the pulp chamber roof and pulp chamber floor can only exist in posterior teeth. The pulp chamber roof and pulp chamber floor of upper and lower teeth are opposite because the upper teeth grow from top to bottom and the lower teeth grow from bottom to top, so the pulp chamber roof is in the direction relative to the crown, that is, the pulp chamber roof of the upper teeth is below and the pulp chamber roof of the lower teeth is above.