Impact of Diatomaceous Earth Addition on Toothpaste Performance | Qian Cao Tang Toothpaste

1. Impact on Toothpaste Stability

The addition of diatomaceous earth (DE) plays a key role in determining the overall stability of toothpaste formulations. Research indicates that DE influences product stability in several aspects:

1. Rheological properties:
   DE improves the rheological behavior of toothpaste by optimizing thixotropy and viscosity, thereby enhancing extrusion performance and shape retention. Studies show that toothpaste containing a moderate amount of DE maintains a stable shape after extrusion—resisting flow or collapse—while ensuring excellent dispersibility and spreadability during brushing.

2. System stability:
   Due to its porous microstructure, DE can absorb water and active ingredients, preventing phase separation and sedimentation. This enhances the long-term physical stability of toothpaste. In transparent or semi-transparent systems, DE helps reduce stratification during storage, maintaining product uniformity over time.

3. Antimicrobial stability:
   DE exhibits inherent antibacterial properties, inhibiting microbial growth within the toothpaste and thereby extending shelf life. Additionally, DE can adsorb substances that cause spoilage, further reinforcing microbial stability.

However, the concentration of DE must be properly controlled. Studies suggest that when DE content exceeds 12%, the toothpaste may become overly viscous, impairing extrusion performance and user experience. Thus, formulation design should balance DE dosage according to the product type and desired properties.

2. Impact on Toothpaste Sensory Experience (Mouthfeel)

The influence of DE on toothpaste mouthfeel is another important consideration. Its effect is mainly reflected in the following dimensions:

• Texture perception:
  The particle size of DE significantly affects tactile feel. DE with particle sizes in the 10–28 μm range provides a balanced level of friction—effective for cleaning without being abrasive to enamel. In particular, DE with an average size of around 15 μm achieves the optimal balance between cleaning efficiency and comfort.

• Flavor release:
  The porous structure of DE allows it to adsorb and gradually release flavoring agents, extending the freshness sensation. Tests show that DE-containing toothpaste maintains a longer-lasting minty freshness after brushing.

• Residue-free feel:
  DE is odorless and tasteless, leaving no unpleasant residue in the mouth. On the contrary, it helps adsorb residual odor compounds, improving overall oral comfort.

• Synergistic interaction with other ingredients:
  DE interacts synergistically with other components such as sweeteners and cooling agents. For example, it can adsorb and slowly release menthol, prolonging the cooling sensation.

Consumer usage studies indicate that toothpaste containing an appropriate level of DE offers a pleasant, refreshing, and natural mouthfeel, well accepted by users—especially those preferring mild and natural oral care formulations.

3. Impact on Other Functional Properties

Beyond stability and mouthfeel, DE also enhances several functional aspects of toothpaste:

• Cleaning and whitening:
  DE effectively removes stains and dental plaque, improving cleaning performance. Its adsorption capacity also removes pigments on the enamel surface, contributing to teeth whitening. Studies demonstrate superior removal of tea, coffee, and tobacco stains compared with conventional toothpaste.

• Anti-caries protection:
  DE can adsorb fluoride ions and release them slowly, strengthening anti-caries protection. Additionally, it supports mineral balance on the tooth surface, helping prevent decay.

• Antibacterial effect:
  DE inhibits common oral pathogens such as Streptococcus mutans and Porphyromonas gingivalis, contributing to overall oral health maintenance.

• Remineralization:
  DE promotes remineralization of enamel, enhancing acid resistance and reducing tooth sensitivity and decay risk.

• pH regulation:
  DE adsorbs acidic substances in the oral cavity, helping maintain a neutral pH environment that suppresses bacterial growth and reduces halitosis and caries formation.

Overall, the inclusion of DE not only enhances deodorizing and cleaning efficacy but also improves the overall performance and functionality of toothpaste, providing users with a more comprehensive oral care experience.

4. Summary

Analysis of diatomaceous earth in toothpaste formulations highlights its multidimensional performance advantages, along with practical considerations:

• Stability: Optimizes rheological behavior for better extrusion and form retention, prevents phase separation, provides antimicrobial protection, and extends shelf life. However, excess (>12%) may cause over-thickening.

• Mouthfeel: Ideal particle size (10–28 μm, best at ~15 μm) ensures balanced friction; porous structure supports flavor adsorption and slow release for long-lasting freshness; odorless and residue-free.

• Functional enhancement: Improves cleaning and whitening, boosts anti-caries and antibacterial properties, promotes remineralization, and balances oral pH.

In summary, diatomaceous earth serves as a high-performance multifunctional additive, elevating toothpaste quality from both a sensory and functional standpoint—delivering superior freshness, protection, and comfort in daily oral care.