What are pits & fissures?

• A. Smooth surfaces
• B. Deep occlusal depressions
• C. Fossa & grooves that failed to fuse during development
• D. Cavitated lesions

Answer: (C)

Pits and fissures are the enamel features that form when adjacent developmental lobes or cusps fail to fuse during tooth formation. This leaves a fossa (pits) and narrow grooves (fissures) on the chewing surfaces, most commonly on the occlusal surfaces of posterior teeth. These tight crevices trap plaque and food particles and are difficult to clean with a brush, which is why they’re especially prone to caries if not protected. So the best description is that pits and fissures are fossa and grooves that failed to fuse during development. They aren’t smooth surfaces, and they aren’t simply deep depressions by themselves, nor are they cavitated lesions—though decay can develop within them if not treated.