Maxillary molars have two buccal cusps and two lingual cusps. Its lower molars are bilophodont with low cusps. Drawing an Occlusal Plane through the overlapping cusps of Molars and Premolars. The first two molars have cusps in a straight row, and interlocked during biting. Premolars are primitive, with one primary cusp and various secondary cusps. The crown, which has two cusps (bicuspid), is attached to a pedicel by collagenous fibers. The thickenings are the origins of the three cusps of the semilunar valves. The involved cusp can be determined by biting on individual cusps separately. "Thrinaxodon" are all tricuspid with no labial or cingular cusps. Aortic stenosis most commonly is the result of calcification of the cusps. The two smaller labial cusps are located on an expanded shelf called the stylar shelf. Well-defined wear facets appear on tooth cusps or ridges. Deciduous teeth are unlikely to have talon cusps. The invaginated margins form the rudiments of the lateral cusps of the AV valves. Gnarled enamel is found at the cusps of teeth.