What is the order of surfaces from most to least susceptible to dental caries?

Occlusal surfaces are the most susceptible to dental caries because pits and fissures trap bacteria and food debris, making them difficult to clean and ideal for plaque accumulation. Interproximal (proximal) surfaces are the second most susceptible due to plaque retention below the contact point and reduced access for cleaning. Buccal smooth surfaces are least susceptible because they are self-cleansing through tongue and cheek action, and caries can be detected and arrested more readily. In children, occlusal caries in first molars typically develop first.