Which teeth are most susceptible to pit and fissure decay?

• A. The first and second permanent molars
• B. Central incisors
• C. Third molars
• D. Primary molars

Answer: (A)

Pit and fissure decay occurs where the enamel surface has deep, irregular pits and grooves that trap plaque and are hard to clean. The first and second permanent molars are especially prone to this because they erupt early and their occlusal surfaces develop complex, deep fissures. Those grooves create sheltered niches where cariogenic bacteria can thrive, and because these teeth come in early, they face prolonged exposure to dietary sugars before routine brushing and professional sealant use become fully established. The combination of challenging anatomy and long exposure makes them the most susceptible sites for pit and fissure decay.

Other teeth can have pits and fissures too, but their surfaces are typically smoother or have less pronounced fissures, or they don’t stay exposed to the same cleaning challenges for as long. Third molars vary a lot in their eruption and anatomy, and primary molars, while they do have pits, generally do not accumulate caries in the same pattern on their occlusal pits as the first and second permanent molars do. This is why protecting the first and second permanent molars with preventive measures like sealants is a key focus in caries prevention.