Relative Dentin Abrasivity (RDA)

Main thing

Relative Dentin Abrasivity (RDA) is a measure of the erosive effect of toothpaste on tooth dentin. It's a method that uses standardized abrasives compared against the toothpaste sample. The RDA value tells us how hard a toothpaste is on your teeth, and it's important because it determines how quickly your teeth will wear away. This wear can be responsible for occlusal wear and pitting, and also gumline NCCLs.

RDA values are not usually put onto the labels of toothpaste. The data can be hard to come by and may be inaccurate to some extent. However, it's generally agreed that a toothpaste with an RDA level of 70 is considered the best. Tartar control and whitening products are usually more abrasive because the ingredients that allow them to work are abrasive.

The RDA value is set by the standards DIN EN ISO 11609 since 1998. The scale ranges from 0 to 250. Here is a breakdown of the scale:

• 0 to 80: Low abrasion. The lower the number, the less enamel/dentin it is likely to be worn away.

• 70 to 100: Midrange abrasion. This range overlaps with low and high abrasion.

• 100 to 150: Highly abrasive. The higher the number, the more wear on your dentition.

• 150 to 250: Considered harmful to teeth. This range is considered potentially damaging to your teeth.

For example, a toothpaste with an RDA value of 50 would be considered low abrasion, meaning it is less likely to wear away enamel/dentin. On the other hand, a toothpaste with an RDA value of 200 would be considered harmful abrasion, meaning it is more likely to cause wear on your dentition.

Terminology

• Relative Dentin Abrasivity (RDA): A measure of the erosive effect of toothpaste on tooth dentin. Example: A toothpaste with a high RDA value can cause more wear on your teeth.

• Dentin: The main, calcified part of a tooth, beneath the enamel. Example: Dentin is exposed when the enamel layer is worn away.

• Abrasion: The process of scraping or wearing away. Example: High RDA toothpaste can cause more abrasion on the teeth.

• DIN EN ISO 11609: The standard that sets the RDA value. Example: According to DIN EN ISO 11609, an RDA value of 70 is considered the best for toothpaste.

An analogy

Think of Relative Dentin Abrasivity (RDA) like sandpaper grades. The lower the grade, the less abrasive it is, and the less damage it does to the surface. Similarly, a lower RDA value means the toothpaste is less abrasive and causes less wear to your teeth.

A main misconception

A common misconception is that the higher the RDA value, the better the toothpaste is at cleaning teeth. However, a high RDA value can actually lead to more wear and tear on your teeth. For example, some people might think a toothpaste with an RDA value of 200 is great because it's highly abrasive and can clean teeth effectively, but it can actually cause more harm than good by wearing away the enamel and dentin.

The history

The concept of Relative Dentin Abrasivity (RDA) was introduced in 1998 when the standard DIN EN ISO 11609 was set. This standard was developed to ensure the safety and effectiveness of toothpaste. Over the years, the understanding and application of RDA values have evolved, with more emphasis now placed on the potential harm of high RDA values. As Dr. Harold Hodge, a renowned toxicologist, once said, "The safety of a product is not determined by the absence of hazard but by the absence of risk."

Three cases how to use it right now

1. Case 1: When choosing a toothpaste, you can look for the RDA value to ensure it's not too abrasive for your teeth. The main benefits of using this knowledge are: you can protect your teeth from unnecessary wear and tear, and maintain good dental health. For example, choosing a toothpaste with an RDA value of 70, which is considered the best according to DIN EN ISO 11609.

2. Case 2: If you're experiencing sensitivity or noticing wear on your teeth, you can check the RDA value of your toothpaste. The main benefits of using this knowledge are: you can identify if your toothpaste is contributing to the problem, and switch to a less abrasive toothpaste if necessary. For example, if you're using a toothpaste with an RDA value of 150, switching to one with a lower RDA value could help reduce sensitivity and wear.

3. Case 3: If you're a dental professional, you can use RDA values to recommend suitable toothpaste to your patients. The main benefits of using this knowledge are: you can provide personalized advice based on your patient's dental health, and help them maintain healthy teeth. For example, recommending a toothpaste with a low RDA value to a patient with sensitive teeth.

Interesting facts

1. The RDA value is not usually put onto the labels of toothpaste.

2. Tartar control and whitening products are usually more abrasive.

3. The RDA value is set by the standards DIN EN ISO 11609 since 1998.

4. A toothpaste with an RDA level of 70 is generally considered the best.

5. The scale ranges from 0 to 250, with 0 to 80 considered low abrasion, 70 to 100 midrange abrasion, 100 to 150 highly abrasive, and 150 to 250 considered harmful to teeth.