A lower permanent second molar usually has how many roots and cusps?

A lower permanent second molar usually has how many roots and cusps?

• A. Three Roots, Five Cusps
• B. Two Roots, Four Cusps
• C. One Root, Two Cusps
• D. Two Roots, Six Cusps

Answer: (B)

The main idea here is the typical anatomy of a lower permanent second molar. In this tooth you normally find two roots—one mesial and one distal—and four cusps on the biting surface: mesiobuccal, distobuccal, mesiolingual, and distolingual. This combination gives the common two-root, four-cusp pattern dentists expect when assessing a second molar. While there can be rare variations, such as additional cusps or unusual root configurations, the two-root and four-cusp arrangement is the usual norm for this tooth.

The main idea here is the typical anatomy of a lower permanent second molar. In this tooth you normally find two roots—one mesial and one distal—and four cusps on the biting surface: mesiobuccal, distobuccal, mesiolingual, and distolingual. This combination gives the common two-root, four-cusp pattern dentists expect when assessing a second molar. While there can be rare variations, such as additional cusps or unusual root configurations, the two-root and four-cusp arrangement is the usual norm for this tooth.