Diffusion in dentin is related to which factor?

• A. Dentin thickness
• B. Pulp vitality
• C. Tooth color
• D. Root length

Answer: (C)

Diffusion through dentin describes how substances move from the external surface into dentin via the dentinal tubules. The most direct, observable outcome of this movement is tooth color. Pigments or staining agents that diffuse into dentin can cause intrinsic discoloration, especially when dentin is exposed or thinner, making color changes more noticeable. While factors like dentin thickness or tubule density influence how much diffusion occurs, the clinical consequence students most often track is changes in tooth color. Pulp vitality or root length are less directly tied to the diffusion process in terms of the observable outcome described here.