Erbium-based laser systems used in cavity preparation have which characteristic?

• A. They are not suitable for bonding.
• B. They have wavelengths with small penetration depths so no heat transfer to the pulp.
• C. They only work on soft tissue.
• D. They require high energy to cut enamel.

Answer: (B)

Erbium-based lasers cut hard dental tissue mainly through a water-driven, micro-explosive ablation process. The wavelength is strongly absorbed by water in enamel and dentin, so energy is spent at the surface and tissue is removed with minimal thermal diffusion. This creates a very shallow penetration depth, which limits heat transfer toward the pulp when the energy is properly controlled. That minimal heat transfer is a key advantage during cavity preparation, helping preserve pulp vitality. Bonding compatibility is possible with appropriate surface conditioning, and these lasers are effective for hard tissue, not limited to soft tissue; they do not inherently require high energy to cut enamel, as the efficient, short-pulse interaction achieves ablation with controlled energy.