Can fluoride diffuse through calculus?

The idea that fluoride cannot diffuse through calculus is based on the nature of the calculus itself. Calculus, which consists of hardened dental plaque, creates a dense structure that is not permeable to many substances, including fluoride. This impermeability means that fluoride, which is typically used for its caries-preventive properties, cannot effectively penetrate through calculus to reach the underlying tooth structure where it could provide benefit.

This characteristic of calculus being a barrier highlights why dental hygiene practices focus on the removal of calculus during cleanings. The primary purpose of fluoride treatments is to aid in remineralization and prevent decay, but if it's trapped beneath calculus, it cannot fulfill that role efficiently.

Considering other potential answers reveals their limitations: fluoride cannot partially diffuse through calculus, nor does its ability to diffuse depend on the type of calculus. The consistent composition of calculus as a barrier remains the same across different types, supporting the assertion that fluoride diffusion simply does not occur.