The order of caries susceptibility of primary teeth is:
2nd molar>1st molar>canine
1st molar>2st molar>canine
Canine>1st molar>2nd molar
Canine>2nd molar>1st molar
Caries susceptibility of primary teeth (in descending order)
2nd molar > 1st molar > canine > lateral incisor > central incisor
Caries susceptibility of permanent teeth (in descending order)
1st molar > 2nd molar > Max. 2nd PM > Max. 1st PM & Mand. 2nd PM > Max. central & lateral incisor > Max. canine & Mand. 1st PM > Mand. Central & lateral incisor > Mand. canine
Surfaces involved in descending order (in primary teeth)
 Occlusal > molar interproximal > incisor interproximal. (Proximal surfaces were affected more in first than in second primary molars).