Final answer:
Developmental grooves are what separate the cingulum on an anterior tooth from the labial lobes. These grooves mark the boundaries of the lobes and provide distinctions in the tooth's topography.
Step-by-step explanation:
What separates the cingulum on an anterior tooth from the labial lobes are developmental grooves. The cingulum is a convexity on the cervical third of the lingual surface, formed during the development of the tooth. The labial lobes, on the outer surface of the tooth, give rise to the tooth's cusps and incisal edges. Developmental grooves are slight depressions in the enamel that indicate the boundaries of the lobes and help distinguish the cingulum from these lobes.