Titanium dioxide (TiO2) is a common toothpaste ingredient that is used to give the toothpaste its characteristically white color. However, it is technically an opacifier but it can also be used for reducing teeth sensitivity and increasing acid erosion resistance.
Below is a concise summary with things to know about TiO2 when used in toothpaste. Clicking each link will take you to more in depth information or you can simply scroll.
Titanium dioxide in toothpaste overview
Description: White solid naturally occurring inorganic compound.
Toothpaste Benefits: White colorant; Opacifier; Anti-sensitivity; Erosion resistance.
Side effects: Cytotoxicity; Genotoxicity; Immune response; Yellow nails syndrome
Safety: FDA approved; Banned in EU as food additive.
Abrasiveness: 5.5-6.5 on Mohs hardness scale.
What is titanium dioxide?
Titanium dioxide is a naturally occurring inorganic compound that is a white colored solid. It is odorless, tasteless, and insoluble in water with a 7.5 pH. The main function for TiO2 is as a white colorant to give products an opaque white color.
Where it comes from:
Main source of it is from the mineral ilmenite.
Naturally occurring form of it comes from the minerals rutile and anatase.
Food additives - chewing gum, sweets, candies, coffee creamers, sauces, etc.
Cosmetic products - sunscreen, make up, face creams, shampoos, deodorants, etc.
Household products - paint, coloring.
Oral care products - toothpaste ingredient.
Essentially if you see a white colored product (including food) it probably has it in it.
Why is titanium dioxide in toothpaste?
The main purpose of having titanium dioxide in toothpaste is to give the paste a white color especially if it is mint flavored, which is the majority of toothpastes. Yes, that opaque white color that you're used to seeing is predominantly derived from the addition of TiO2.
However, unbeknownst to most it does more than just add a white color because it can also assist with dentin hypersensitivity as well as protect against acid erosion.
Below is a video showing the differences between toothpastes with titanium dioxide vs those without it. You can literally see the difference.
TiO2 benefits in dentifrices:
Colors the toothpaste white.
Opacifies the color and reduces translucency.
Reduce sensitivity when combined with egg shell.
Increase resistance to acid attacks.
White colorant
One of the most common uses for adding titanium dioxide to products is as a white colorant. Yes, that means if you want your product whether that be toothpaste, food, or cosmetics to look white, you include it as an ingredient.
Below is a picture of two toothpastes which contain it, Ollie's and Sensodyne pronamel intensive enamel repair.
Clearly, the color of the paste is very white looking but it is very typical for these mint flavored toothpastes to look this color.
Opacifier
In addition to adding white color to the toothpaste, TiO2 is also used as an opacifier. Put another way, adding it in as an ingredient will make the paste look less translucent or less see-through.
Below is an image of two toothpastes that are titanium dioxide free, Boka ela mint and hismile pap+ whitening toothpaste.
Objectively, these two toothpastes have a much more translucent color when you compare them to toothpastes which do have the opacifier. This is especially true with the hismile in that its paste almost looks clear.
Sensitivity reduction
Interestingly, when titanium dioxide is combined with calcium carbonate as toothpaste ingredients, it resulted in a reduction of teeth sensitivity. That is an effective which does not occur without calcium carbonate.
Studies have demonstrated that when calcium carbonate (egg shells) is combined with it, it led to occlusion of exposed dentinal tubules. Consequently that meant a decrease in sensitivity.
This is fabulous news because the conclusion of the study was that this could potentially be a cost effective alternative to more costly means of reducing sensitivity. That is because other ingredients which can desensitize teeth often cost more.
More costly desensitizers:
Stannous fluoride - premium version of fluoride which occludes open tubules.
Hydroxyapatite - literally made of tooth mineral, also known as a synthetic enamel paste. This will also occlude exposed dentinal tubules.
Acid erosion resistance
The last benefit of titanium dioxide is an increase in acid erosion resistance when used with calcium carbonate (egg shells). Studies have shown that it will improve acid resistance and help remineralize teeth.
Another study found that it reduced acid attacks and did not interfere with the oral buffering environment when used with calcium carbonate. Overall it seems to be a very helpful and useful ingredient in toothpaste.
Side effects
Below is a list of potential adverse effects from excessive titanium dioxide:
Cytotoxicity
Genotoxicity
Decrease in body weight
Increase in weight of liver, kidney, spleen, thymus
Triggers immune response (pulmonary and systemic).
Yellow nail syndrome (from swallowing toothpaste).
The good news is that at least it wasn't carcinogenic meaning it did not cause cancer.
Is titanium dioxide safe in toothpaste?
Titanium dioxide as a colorant is deemed safe to be used in toothpaste as well as cosmetic products by the FDA (21CFR73.2575).
However, the European Food Safety Authority’s (EFSA) 2021 Opinion concluded that, "titanium dioxide “can no longer be considered safe when used as a food additive.”
The result of the EFSA's decision was a BAN on using it as a food coloring additive beginning August 7th, 2022. Yes, it is currently not legal to use it as a white coloring for food in the european union.
Nonetheless, the FDA has review the EFSA's opinion but has decided to reaffirm that TiO2 is still safe to use in the US. An exerpt of the FDA's statement can be found below.
preventative dentistry"The FDA reviewed the findings of EFSA’s 2021 Opinion on titanium dioxide. The FDA notes that EFSA’s 2021 Opinion continued to confirm no general and organ toxicity, as well as no effects on reproductive and developmental toxicity. In its 2021 Opinion, EFSA noted that it could not rule out genotoxicity and included genotoxicity tests on titanium dioxide nanomaterials. Some of the genotoxicity tests included test materials not representative of the color additive, and some tests included administration routes not relevant to human dietary exposure. The available safety studies do not demonstrate safety concerns connected to the use of titanium dioxide as a color additive. The FDA continues to allow for the safe use of titanium dioxide as a color additive in foods generally according to the specifications and conditions, including that the quantity of titanium dioxide does not exceed 1% by weight of the food, found in FDA regulations at 21 CFR 73.575."
What research says
Here at afterva, we are more inclined to side with the FDA on this matter based on the research studies that we've reviewed.
The facts:
The 2021 report found no signs of general/organ/reproductive/developmental toxicity when up to 1000 mg/kg of TiO2 were consumed per day.
Studies have found that if 10% of a titanium dioxide toothpaste was ingested during brushing, you would get 0.15-3.9 mg of TiO2 per day.
In conclusion, even if you accidentally swallow some toothpaste every day, you are still nowhere close to toxicity limit of titanium dioxide. Even if you swallowed 100% of the regular amount of toothpaste, you would still only get 39 mg of TiO2 at most. That is still 25x below the safety limit.
Therefore in our opinion, it is a relatively safe toothpaste ingredient.
Abrasiveness
Titanium dioxide is abrasive on the enamel and can potentially scratch it because it has a 5.5-6.5 on Mohs scale of hardness. That means it is harder than enamel.
Mineral | Mohs Hardness Scale |
|---|---|
Calcium Carbonate | 3 |
Hydroxyapatite (Enamel) | 5 |
Titanium Dioxide | 5.5-6.5 |
However, you shouldn't be concerned about its enamel safety because there is typically very little TiO2 in toothpaste. If you look at the ingredients, it is usually towards the end of the ingredient list, signifying a very low concentration.
The image above shows the inactive ingredients from the Colgate Total toothpaste. As you can see, the TiO2 is literally the last ingredient. In summary, it may be harder than enamel and can be abrasive but that is why manufacturers put very little of it. This is done to protect your dentition. Last but not least it is a widely used ingredient in preventative dentistry.
