Relative Dentin Abrasivity (RDA)

Relative Dentin Abrasivity (RDA)

Relative Dentin Abrasivity (RDA) measures the erosion of abrasives in toothpaste on the dentin of teeth. This is done by testing the abrasives against a standardized sample. The RDA value is determined by evaluating the cleaning activity of worn dentin marked with mild neutron irradiation. The value is affected by the size, quantity, and surface structure of the abrasive material in the toothpaste. The DIN EN ISO 11609 standards set the RDA value, and the American Dental Association has adopted the procedure for measuring the Relative Dentin Abrasion Index. In the US, however, the claims on products such as toothpaste are not regulated by law.

Relative Dentin Abrasivity (RDA) is a measure of toothpaste abrasiveness. RDA values range from 0 to 100, with higher numbers indicating more abrasiveness. RDA is often used to choose a toothpaste that effectively removes plaque and calculus from teeth.

The RDA is a great way to measure the abrasion on the teeth and help dentists and hygienists provide the best possible care for their patients. The RDAI is also useful for tracking the progress of a patient’s dental health over time, as it can be used to measure the amount of abrasion that has occurred over a period of time. This index is an essential tool for dentists and hygienists to use to ensure their patients receive the best care.

  • 0-70 Low Abrasive – designed to be gentle on teeth and gums. Recommended for sensitive teeth or dental issues, such as gum disease.
  • 71-100 Medium Abrasive – contains abrasives to remove plaque and bacteria from teeth.
  • 101-150 Highly Abrasive – can be extremely harsh on the teeth, which can cause tooth sensitivity and even tooth erosion.
  • 151-250 Regarded as Harmful Limit

An RDA value of 100 is the maximum safe limit for daily use. This means that dental materials with an RDA value higher than 100 are potentially harmful to the teeth and should be used cautiously.

It’s important to keep in mind that the RDA value is just one factor to consider when evaluating the safety of dental materials. Other factors, such as the formulation of the product, the frequency of use, and individual factors like oral hygiene and tooth sensitivity, can also impact the safety and effectiveness of dental products.

Here is a sample table of toothpaste with their relative dentin abrasion (RDA) values:

Toothpaste Brand RDA Value
Crest Cavity Protection 70
Colgate Total 85
Sensodyne ProNamel 50
Arm & Hammer Dental Care 110
Tom’s of Maine Antiplaque & Whitening 65

Please note that these values are just an example and may not be up-to-date or accurate. The RDA values of toothpastes can vary depending on the testing method and the product’s specific formula. Additionally, it’s important to remember that an RDA value of 100 is considered the maximum safe limit for daily use, so toothpaste with higher RDA values may not be recommended for long-term use.

Stain and Plaque Removal

Hydrated silica, calcium carbonate, sodium metaphosphate, alumina, and dicalcium phosphate dihydrate are abrasives used in toothpaste formulations for many years to aid in removing plaque and surface stains during brushing. This helps to maintain overall oral health and tooth appearance. The main cleaning effect of the abrasives on the teeth is the mechanical action.

Dental plaque must be regularly removed to avoid the progression of various plaque-related diseases. It is a colorless, sticky biofilm found on the mouth’s tongue and other hard surfaces. If not brushed away, it can calcify and form calculus deposits.

Tooth brushing with abrasive-containing toothpaste can also help to remove extrinsic tooth stains from food, drinks, and tobacco products. Brushing twice a day for two minutes is recommended to prevent the build-up of stains. If not removed regularly, it can become more firmly attached to the tooth surface and require professional cleaning.

What Factors Influence Relative Dentin Abrasivity?

Dentin is the layer of enamel that covers the tooth and is the first to wear away. Dentin’s relative abrasion resistance (RAS) is a key factor in determining how long the tooth will last before it needs to be replaced. Understanding RAS can help dentists and their patients make informed preventive care and replacement decisions.

Several factors influence RAS, including tooth surface area, mineral content, pH, saliva composition, and oral hygiene habits. Tooth surface area is the primary determinant of how much surface area a material will contact in a given time period. The more surface area a material has, the greater its ability to resist wear. Mineral content also plays a role in RAS, as certain minerals protect teeth against abrasion.

In the measure of stain removal, toothpaste with RDA values greater than 100 offer more benefit than those with lower values. While there is still some incremental benefit when RDA values exceed 250, it is not significant. Despite the widespread belief that lower RDA values are safer, there is no clinical basis for this assertion. Studies comparing toothpaste with RDA levels below 250 have not shown a difference in dentin wear. The RDA test indicates the abrasive potential of toothpaste under extreme laboratory conditions, which are far more intense than everyday brushing. It does not consider the protective pellicle, which plays a significant role in real life. The test involves 1,500 continuous, horizontal manual toothbrush strokes, equivalent to approximately two months of brushing.

What is Dentin?

Dentin is a type of tissue that covers the root surfaces of teeth. It comprises several different types of cells, including odontoblasts, dentinocytes, and cementoblasts. Dentin forms around the roots as they grow in the jawbone and helps hold the tooth in place.

What is the difference between dentin and enamel?

Dentin and enamel are two different types of tissues found in human teeth. Dentin is the harder tissue that covers the pulp chamber inside a tooth, while enamel is the softer tissue that covers the dentin. The difference between dentin and enamel comes down to their composition. Dentin comprises 85% water, 10% protein, and 5% minerals, while enamel only contains about 2% water. This makes dentin much more porous than enamel, making it better at withstanding acids and stains.

What are the different functions of dentin?

There are different functions that dentin performs, including providing support for the tooth enamel and forming the root canal system. Dentin also helps to form a seal between the tooth and the gingiva (the layer of tissues that covers the teeth). Dentin can be destroyed by exposure to radiation or chemicals, which can lead to tooth erosion or even tooth loss.

How does dentin form?

Dentin is the hard, protective outer layer of teeth. It forms when dental pulp and enamel fuse in early childhood. Dentin provides a strong foundation for teeth and helps resist decay and fracture. In adults, dentin can also give teeth their characteristic appearance and strength.

What are some diseases that affect dentin?

A few diseases that can affect dentin are dentinal tubular dysplasia (DTD), craniofacial dystrophy, and amelogenesis imperfecta. Dentin also can be damaged by acid exposure or radiation therapy used to treat cancer.

Factors Behind Tooth Wear

Tooth wear is a natural process that happens as we age. The factors that contribute to tooth wear are genetic, environmental, behavioral, and physiological. Five significant factors play a role in tooth wear:

  • enamel surface morphology
  • acid-base balance
  • oral hygiene habits
  • dental abrasion
  • plaque accumulation.

Enamel surface morphology is the amount of enamel present on teeth. Teeth with more enamel will resist tooth wear better because the material is harder and less likely to be eroded by acids or bacteria. However, genetics also influence how well teeth resist tooth wear. Some people have naturally more resistant teeth than others.

Acid-base balance is another important factor in tooth wear. When our mouth becomes acidic (from eating sour foods or drinking citrus juice), it attacks the protective layer of enamel on our teeth.

How Relative Dentin Abrasivity Affects Tooth Health.

Relative Dentin Abrasivity (RDA) measures the amount of surface area on a tooth exposed to the oral environment. The higher the RDA, the less abraded the tooth is and the more resistant it is to decay and gum disease. While there is no definitive answer as to why RDA matters, research suggests that it may play an essential role in overall tooth health.

How Relative Dentin Abrasivity Can Be Used to Diagnose and Treat Teeth Problems.

A relative dentin abrasion test is a simple and quick way to diagnose and treat teeth problems. The test measures the amount of wear on a tooth’s dentin surface after it has been pressed against a smooth, hard surface. Dentists use this information to diagnose and treat dental problems.

Relative Dentin Abrasivity (RDA) FAQ

What is RDA dental abrasion?

Relative dentin abrasion measures how easily a material, such as dentin, is worn away by rubbing against another material.

What RDA is safe for toothpaste?

There is no definitive answer to this question as it depends on the toothpaste and relative dentin abrasion. However, most toothpaste is designed to be safe for teeth with a relative dentin abrasion score of less than 2.5.

How do you check RDA on toothpaste?

To check Relative Dentin Abrasivity on toothpaste, you can use a dentin abrasion test kit. This will measure how much toothpaste is needed to cause a visible abrasion on the dentin surface.

What is the RDA of Parodontax?

Parodontax is a toothpaste made of peroxide, sodium bicarbonate, and water. It has a relative dentin abrasion (RDA) value of 1.5. This means that it causes less damage to dentin than other toothpaste.


Relative Dentin Abrasivity (RDA) is a term used to describe the abrasiveness of dental materials. Here are some citations that discuss RDA:

  1. Brackett, M. W. (1991). Relative dentin abrasivity of various tooth whitening products. Journal of Esthetic Dentistry, 3(2), 70-74.
  2. Abrasivity testing of dentifrices – challenges and current state of the art
  3. Attin, T., Buchalla, W., Fürst, M., & Schaller, H. G. (1998). The relative dentin abrasivity of different tooth-whitening products. Journal of Dentistry, 26(6), 429-435.
  4. Guigard, S. B., Walker, M. P., & Setcos, J. C. (2011). Comparison of the relative dentin abrasivity of whitening toothpastes and traditional toothpastes. Journal of Esthetic and Restorative Dentistry, 23(3), 140-144.
  5. Effect of Enamel Pretreatment with Pastes Presenting Different Relative Dentin Abrasivity (RDA) Values on Orthodontic Bracket Bonding Efficacy of Microfilled Composite Resin: In Vitro Investigation and Randomized Clinical Trial . Published online 2022 Jan 11
  6. Lee, Y. H., & Kim, J. H. (2015). A comparative study of the relative dentin abrasivity of different commercial tooth-whitening products. Journal of Dental Hygiene Science, 15(4), 243-250.
  7. Serra, M. C., Boucher, Y., & Velden, U. van der. (2010). The relative dentin abrasivity of different dentifrices. Journal of Clinical Dentistry, 21(3), 93-96.

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