Toothpaste Abrasivity: What RDA Actually Means and Why It Matters

Most people brush their teeth every day with a paste that scores above 150 on the abrasivity index. For years. Without knowing it — because manufacturers are not required to list RDA on the label.

This is not a conspiracy. It is simply the absence of a legal requirement. In Russia, the EU, and the US, a tube can say "gentle clean" or "safe whitening" while wearing away dentin faster than sandpaper on soft wood.

RDA is the one number that lets you compare toothpastes objectively. We break down what it is, how to read the scale, where popular pastes actually land — and why the right paste depends entirely on the type of toothbrush you use.

What RDA Is and How It Is Measured

RDA stands for Relative Dentin Abrasivity — a standardised measure of how aggressively a paste abrades dentin under controlled laboratory conditions.

The method is defined in ISO 11609:2017. Dentin samples are irradiated with strontium-90, then brushed with the test paste on a machine set to a fixed load and stroke count. After brushing, radioactivity in the rinsing fluid is measured — it is proportional to the mass of dentin removed. The result is compared to a reference abrasive (calcium pyrophosphate) set at 100. ISO 11609:2017 establishes an upper limit of RDA 250; pastes above this value cannot be certified as safe.

Why dentin and not enamel? Because dentin is the most vulnerable tissue in clinical practice. Most adults have some degree of gingival recession, exposed root surfaces, or worn edges — areas where dentin sits exposed without enamel protection.

The RDA Scale: What the Numbers Mean

RDA Range	Category	Typical Pastes
0–30	Ultra-low abrasivity	Children's, Sensodyne Pronamel (~35), post-surgical pastes
30–70	Low abrasivity	Daily-use for sensitive teeth, nHAp pastes
70–100	Standard	Most universal pastes
100–150	High abrasivity	Whitening, anti-tartar pastes
150–250	Very high	Intensive whitening, charcoal pastes
>250	Not certifiable	Non-compliant with ISO 11609

Quick selection matrix:

Situation	RDA
Bleeding gums / sensitivity	<70
Everyday brushing	70–100
Stain removal (2–3×/week)	100–130

Real RDA Values for Popular Pastes

Manufacturers rarely disclose RDA publicly. The figures below are drawn from clinical studies, manufacturer technical sheets, and verified dental databases. Where sources differ, a range is given.

Paste	RDA	Data Source
Sensodyne Pronamel	~35	Clinical data, GSK technical documentation
Biorepair (nano-HAp)	~45–69	Clinical references, Dr. Wolff data
Elmex Sensitive Plus	~28–30	Hamza et al., 2021 (PMC8596782)
Colgate Total Original	~70–100	PMC8596782, PMC11619904
Lacalut White	~100	Manufacturer data
SPLAT Blackwood (charcoal)	~166	PMC10099862, direct measurement
Colgate Optic White	~100–225	Varies by product formulation
Arm & Hammer Advanced White	~106	Manufacturer data

A critical caveat: SPLAT Professional Whitening, PresiDENT Classic, and several other brands have no verified RDA in the public domain. Numbers circulating online have not been confirmed by independent research — and that in itself is a problem.

Why does missing data matter more than it seems? Because "whitening" on the label is a marketing category. RDA 120 and RDA 200 are both "whitening," but their cumulative effect after five years of daily use with a sonic brush is entirely different. Without the number, you cannot evaluate the risk.

Charcoal pastes deserve special mention. Their marketing rests on "naturalness" and "detox." The data says otherwise: PMC10099862 found charcoal pastes consistently score RDA 120–166 — higher than most conventional pastes. And charcoal provides no whitening effect beyond ordinary abrasives, as confirmed by ADA systematic reviews.

Consumers have a right to know how abrasive their toothpaste is. The absence of RDA labelling is not the absence of abrasivity. It is the absence of transparency.

The Paradox: Low RDA Is Not Always Better

The intuition is simple: lower RDA means less wear. This is not always true.

A study (PMC11619904, 2023) produced a striking result: Candida White Diamond paste had an RDA of just 12 — the lowest among all tested pastes — yet caused the greatest enamel loss (9.86 µm). The reason: its formula contains diamond abrasive particles with a REA (Relative Enamel Abrasivity) of 244. RDA measures dentin wear; REA measures enamel wear. These are different metrics and can diverge dramatically.

Additionally, a low-abrasivity paste may remove plaque less effectively — especially with manual brushing and imperfect technique. Enzymatic ingredients (bromelain, papain) and detergents (SLS) help, but they do not fully replace the mechanical work of an abrasive.

When a higher-than-average RDA makes sense:

• Heavy pigment staining from coffee, tea, or red wine in otherwise healthy enamel
• Anti-tartar use in patients prone to calculus build-up
• Application 2–3 times per week, not daily

Enamel and Dentin: Why Tissue Type Determines Paste Choice

Enamel is the hardest tissue in the body (Mohs 5, ~340 VHN). It does not regenerate. Once destroyed by acid erosion or abrasion, it cannot be restored. Dentin is a different story: Mohs 2.5–3.5, ~70 VHN — roughly five times softer than enamel. It is permeated by dentinal tubules through which pain signals travel.

Enamel covers only the crown. Gingival recession exposes the root — where dentin has no protective layer. Add acid erosion from carbonated drinks, and the dentin demineralises further, becoming even softer. A paste with RDA 150 on an exposed root surface wears tissue far faster than on the enamel of a crown.

Paste × Brush × Pressure: The Real Equation

Paste is not the only variable. Dental wear is a function of three factors acting simultaneously: paste abrasivity (RDA), brush type, and brushing force.

Many people treat toothpaste as an isolated choice. In reality, the same paste can be safe with one brush and cause eight times more wear with another. This is not theory — it is measured laboratory fact.

Wiegand et al. (PMC5319671, 2017) — simulated 8.5 years of brushing with an RDA 150 paste:

Brush Type	Dentin Loss Over 8.5 Years
Sonic	21.03 ± 1.26 µm
Oscillating-rotating	15.71 ± 0.85 µm
Manual flat-trim	6.13 ± 1.24 µm
Manual multi-level trim	2.50 ± 0.43 µm

The sonic brush produced 8.4 times more wear than the best manual brush. Same paste. Same force.

Hamza et al. (PMC8596782, 2021) — same sonic brush, different pastes:

Paste RDA	Manual Brush	Sonic Brush	Difference
RDA 28 (Elmex Sensitive)	2.7 µm	3.1 µm	Not statistically significant
RDA 65 (Elmex Kariesschutz)	4.9 µm	6.4 µm	Significant
RDA 121 (Colgate Total)	5.2 µm	9.0 µm	Significant (+73%)

The conclusion is direct: with an RDA 28 paste, the sonic brush behaves like a manual brush. With RDA 121, it causes nearly double the wear.

Bristle stiffness. Research on eroded dentin (PubMed 19346053) showed that bristles with a diameter of 0.15–0.18 mm (soft) cause less wear than 0.20–0.23 mm (medium), though the interaction with abrasive particles is complex — more flexible bristles can drive particles deeper into interproximal spaces. Overall conclusion: soft brush + low RDA = minimum wear.

Practical matrix: brush type × paste RDA

Brush Type	RDA ≤30	RDA 30–70	RDA 70–100	RDA 100–150	RDA >150
Sonic	Excellent	Good	Acceptable	Not recommended	Avoid
Oscillating-rotating	Excellent	Good	Good	Acceptable	Not recommended
Manual (correct technique)	Excellent	Excellent	Good	Acceptable	With caution

Pressure is the third variable, and it is often ignored. Most people brush with 200–400 grams of force. The clinically recommended limit is 150 grams. The difference seems small, but at 400 g + RDA 150 + sonic, abrasive wear multiplies far beyond what lab simulations — typically run at standardised 150–200 g — would predict. Electric brushes with pressure sensors are genuine protection here, not a marketing gimmick.

If you want a deeper look at electric toothbrushes and enamel, it is here: Electric toothbrush and enamel: does it protect or damage?

Whitening Pastes: Abrasive vs Chemical Action

Most pastes labelled "whitening" work mechanically — through abrasion. Hydrogen peroxide, when present, is typically at 0.1–0.5% concentration: too low and too brief in contact time to produce genuine chemical whitening.

Three mechanisms compared:

Abrasive. High RDA (100–200+) scrubs pellicle and surface pigment stains. Fast results, visible effect. The cost: dentin wear over prolonged use, especially with an electric brush.

Peroxide. Works from within — oxidises chromogens in the organic matrix of dentin. Requires ≥3% H₂O₂ and sufficient contact time. In toothpaste, concentration is usually 0.1–0.5%, contact time is seconds. Clinically meaningful whitening is extremely unlikely. In trays with 10% carbamide peroxide — it works (PubMed 29949477).

Nanoparticles (HAp, nano silicon dioxide). Fill micro-surface defects, improving optical properties — the tooth looks lighter due to changed light scattering. No chemical whitening, but no abrasive wear either.

There is a fourth mechanism rarely discussed: blue covarine — a dye that deposits on the tooth surface and optically neutralises yellow tones. Instant visual effect with zero effect on tooth tissue. Found in Colgate Luminous White and several European pastes.

Sensitive Teeth: A Different Logic

Heightened sensitivity is usually a sign of exposed dentin. Hot, cold, acidic, sweet — the stimulus travels through dentinal tubules and registers as pain.

Pastes for sensitive teeth work through several mechanisms:

• Potassium nitrate (KNO₃) — depolarises nerve endings, reducing pain signal transmission. Effect appears after 2–4 weeks of consistent use.
• Nano-hydroxyapatite (nHAp) — integrates into dentinal tubules, partially occluding them, while also remineralising demineralised areas. A 2022 study (PMC8930857) found nHAp pastes comparable to fluoride pastes in remineralisation effect.
• Strontium chloride — shares the mechanism with KNO₃, used historically before potassium nitrate became standard.

Why Biorepair (nHAp, RDA ~45–69) is a logical combination: the low RDA avoids additional mechanical irritation of exposed dentin, while nano-HAp actively works on the tubules. This is not marketing — it is a mechanism matched to the problem.

An important note on fluoride: fluoride pastes also remineralise, but through a different pathway — fluorapatite is less soluble than hydroxyapatite and more acid-resistant. For sensitive teeth, there is no need to choose between fluoride and nHAp as an either/or. Some pastes combine both. The key constraint: RDA should be ≤50, otherwise the active ingredient cannot do its job while mechanical irritation is ongoing.

That said: if recession is progressing and sensitivity is worsening, paste manages symptoms but does not treat the cause. A dentist is needed.

Brushing frequency is another overlooked factor in sensitivity discussions. Low RDA does not mean three times daily is safe. Twice a day is the standard. Three or more times adds mechanical stress to tissue that is already compromised.

Practical Selection Matrix

Situation	Paste RDA	Brush Type	Bristle Stiffness
Healthy enamel, no issues	70–100	Any	Soft
Recession or sensitivity	≤50	Electric with pressure sensor	Extra soft
Braces	50–70	Oscillating (ortho head)	Soft
Implants, crowns	≤70	Sonic or manual	Soft
Coffee and tea staining	100–150	Manual or oscillating	Soft
Post-professional cleaning (1–2 weeks)	≤30	Manual	Extra soft
Child aged 6–12	≤50	Children's electric	Children soft

This matrix is not a strict protocol. It is a coordinate system. Your dentist may adjust the parameters based on your individual clinical picture.

QDRO's Position: Transparency Is the Minimum, Not a Virtue

We do not consider disclosing RDA an achievement. It is basic respect for the buyer.

Manufacturers hide RDA for various reasons: some do not measure it, others measure and prefer not to explain the result. No legal obligation — no label. Convenient.

QDRO will publish RDA for all v.daily products. Target range: ≤70 for everyday use. This is a deliberate constraint: a toothpaste should clean teeth, not grind them away.

The QDRO v.pro brush uses Pedex bristles at 0.10 mm diameter — ultra-soft. Combined with an RDA ≤70 paste, this gives the minimum possible abrasive wear while maintaining effective cleaning. The Wiegand and Hamza data are not advertising copy. They are physics.

You have the right to know what you are brushing with. We intend to show it.

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Getting the Combination Right

RDA is only part of the equation. The outcome is determined by the combination: brush × paste × technique.

Everyday paste: RDA 40–80. This is the zone where cleaning is effective and dentin wear is minimal. If using a whitening paste, limit it to 2–3 times per week.

Electric toothbrush: with an electric brush — especially sonic — choose a paste with RDA <70. Sonic action amplifies mechanical work; the same abrasive acts more aggressively.

Evening remineralisation: paste with nano-HAp 10% or fluoride at 1450 ppm. Apply after brushing — do not rinse for 1–2 minutes. Contact time with the surface matters.

Charcoal pastes: not daily, not with an electric brush. RDA 120–166 is the upper limit of acceptable use — with a manual brush, once a week.

Mouthwash: alcohol-free. Alcohol dries the mucosa and disrupts the buffering properties of saliva. CPC at 0.05% is clinically superior to alcohol in its effect on biofilm.

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Sources:

• ISO 11609:2017 — international standard for toothpastes
• Wiegand A. et al. «Toothbrush abrasivity in a long-term simulation on human dentin depends on brushing mode and bristle arrangement» (2017) · PMC5319671
• Hamza B. et al. «Effect of a sonic toothbrush on the abrasive dentine wear using toothpastes with different abrasivity values» (2021) · PMC8596782
• Tauböck T.T. et al. «Abrasive Enamel and Dentin Wear Resulting from Brushing with Toothpastes with Highly Discrepant REA and RDA Values» (2023) · PMC11619904
• Tschammler C. et al. «Toothpaste Abrasion and Abrasive Particle Content: Correlating High-Resolution Profilometric Analysis with RDA» (2023) · PMC10047781
• Derman S.H. et al. «Relative dentin and enamel abrasivity of charcoal toothpastes» (2023) · PMC10099862
• Limeback H. et al. · PubMed 19346053 — abrasion of eroded dentin: different pastes, different bristle diameters
• Lussi A. et al. «Investigation of erosion and abrasion on enamel and dentine» · PubMed 12956656
• Attin T. «Influence of Bristle Stiffness of Manual Toothbrushes on Eroded and Sound Human Dentin» · PMC4829200
• Steinert L. et al. «The use of hydroxyapatite toothpaste to prevent dental caries» (2022) · PMC8930857
• ADA Oral Health Topics: Toothpastes · ada.org