Which statement about Erbium lasers is true?

• A. Erbium wavelength reduces energy required for caries ablation due to water affinity
• B. Erbium lasers require more energy than CO2 lasers
• C. Erbium lasers are not absorbed by water
• D. Erbium lasers are used only in soft tissue

Answer: (A)

Erbium-doped YAG lasers emit at a wavelength that is highly absorbed by water, and dental tissue contains water that can rapidly heat up and vaporize when energy is absorbed. This strong water absorption causes precise, efficient ablation of hard tissue with minimal heat spreading to surrounding areas. In caries, the lesion has relatively more water content, so the laser energy is absorbed effectively, allowing tissue removal at lower energy levels than other wavelengths. That’s why the statement about reduced energy for caries ablation due to water affinity is the best choice. The other ideas aren’t correct: the laser is absorbed by water (not avoided), it’s used for hard tissue as well as soft tissue, and it does not inherently require more energy than CO2 lasers for ablation.