Which statement about peroxide diffusion is supported by the text?

Which statement about peroxide diffusion is supported by the text?

• A. Peroxides can reach the pulp after passing through enamel
• B. Peroxides cannot reach pulp
• C. Peroxides only affect enamel
• D. Peroxides degrade enamel without reaching pulp

Answer: (A)

Diffusion of peroxide through dental tissues to reach the pulp is possible, because bleaching agents move along concentration gradients and enamel, while highly mineralized, is not an absolute barrier. Hydrogen peroxide molecules are small enough to seep through the tiny porosities and interprismatic spaces in enamel and then travel through dentin via the dentinal tubules toward the pulp. This pathway explains why peroxide can reach the pulp after passing through enamel, especially when enamel is thinner, dentin tubules are more exposed, or exposure duration and concentration are high. Clinically, this underpins why whitening agents can cause pulp sensitivity and why practitioners use barriers, lower concentrations, or shorter exposures to minimize pulpal diffusion. The other statements conflict with this mechanism: diffusion to the pulp is not ruled out, so the peroxide isn’t limited to enamel only, and it doesn’t always degrade enamel without reaching the pulp.

Diffusion of peroxide through dental tissues to reach the pulp is possible, because bleaching agents move along concentration gradients and enamel, while highly mineralized, is not an absolute barrier. Hydrogen peroxide molecules are small enough to seep through the tiny porosities and interprismatic spaces in enamel and then travel through dentin via the dentinal tubules toward the pulp. This pathway explains why peroxide can reach the pulp after passing through enamel, especially when enamel is thinner, dentin tubules are more exposed, or exposure duration and concentration are high. Clinically, this underpins why whitening agents can cause pulp sensitivity and why practitioners use barriers, lower concentrations, or shorter exposures to minimize pulpal diffusion. The other statements conflict with this mechanism: diffusion to the pulp is not ruled out, so the peroxide isn’t limited to enamel only, and it doesn’t always degrade enamel without reaching the pulp.