Mohs hardness scale assigns dentin a hardness of approximately which range?

• A. 4-5
• B. 3-4
• C. 2-3
• D. 5-6

Answer: (B)

Dentin sits around 3 to 4 on the Mohs hardness scale, which measures scratch resistance. This means dentin is softer than enamel, which is about 5 on the scale. The difference comes from composition: enamel is highly mineralized, making it very resistant to scratches, while dentin contains more organic matrix and less mineral, giving it a softer, more wear-prone character. So the 3–4 range best matches dentin’s relative hardness. If dentin were as hard as 5–6, it would be comparable to enamel, which isn’t the case. If it were as soft as 2–3, it would be even more easily scratched than typically observed in dentin.