Centuries ago, dentistry identified mineral deposits, such as calculus, as the main cause of dental disease. Further research then recognised bacterial infections in the roots and the periodontium as the cause of periodontitis. So, what was the logical solution? To remove calculus completely. Today, we know that calculus has a porous surface that provides a niche environment for bacteria and endotoxins. Endotoxins are not absorbed into the calculus, and they can be easily removed. However, extensive removal of calculus is contra-indicated and counterproductive.