Kaolin

What it is

Kaolin is a white clay whose primary mineral is kaolinite (Al₂Si₂O₅(OH)₄). One of the most abundant minerals in the earth's crust. The largest deposits are in China (Jiangxi Province — from which the name derives: "Kaolin" from Mount Gaoling), Russia, and Europe.

In dentistry, kaolin is used as an abrasive — a component that physically removes dental plaque and pellicle. It is also used in the food industry as additive E559 and in the production of porcelain and paper.

How it works

Mechanical cleaning. Kaolin particles, positioned between toothbrush bristles and the tooth surface, physically remove the pellicle (a thin protein film on enamel) and dental plaque. Effectiveness depends on particle fineness: finer particles clean more gently and more evenly.

Toxin adsorption. Kaolin has a high specific surface area — from 10 to 30 m²/g. This enables it to adsorb bacterial toxins and food pigments from the tooth surface, removing them during rinsing.

Acid neutralization. Kaolin creates a mildly alkaline environment in contact with water (pH approximately 7.5–8). This helps neutralize acids produced during bacterial fermentation of carbohydrates.

RDA Abrasivity Index

RDA (Relative Dentine Abrasivity) is a standardized measure of dentine damage during brushing.

| Abrasive | RDA | |---|---| | Kaolin | 40–70 | | Chalk (calcium carbonate) | 90–120 | | Silica | 60–200 | | Hydroxyapatite | 50–100 |

RDA below 70 is the safe range for daily use according to international standards. Kaolin reliably falls within this zone.

Safety

Biocompatible material. Not absorbed when swallowed. Used in the food industry (E559). No toxicity data. Safe for children.

A notable advantage: kaolin does not interact with active paste ingredients — it does not adsorb fluorides or nano-HAp, unlike some other abrasives.