The benefits of adding mica as an ingredient in toothpaste is as a whitening abrasive and also as a colorant. Therefore, it plays a role in cleaning and whitening the teeth as well as making the paste look aesthetically pleasing.
Mica in toothpaste overview:
Description: A group of 37 types of phyllosilicate minerals.
Benefits: Whitening abrasive, Glittering colorant.
Side effects: Respiratory issues.
Safety: FDA approved for toothpaste use.
Abrasiveness: 2.5-4 on Mohs hardness scale.
What is Mica?
Mica or rather "Micas" refer to a group of 37 different phyllosilicate minerals which can be naturally found. Therefore when you see mica in toothpaste, it doesn't necessarily tell you specifically what it is.
Examples of mica:
Igneous rocks
Muscovites - granites, granitic pegmatites, aplites
Phlogopites - peridotites, kimberlites
Biotites - gabbros, norites, diorites, syenites, granites, pegmatites
Lepidolite and Zinnwaldite - pegmatites and high temperature veins.
Metamorphic rocks
Muscovite, paragonite, and biotite: phyllites, schists, and gneisses.
Phlogopite: metamorphosed limestones and dolomites.
Sedimentary rocks
Muscovite and paragonite: detrital and authigenic sediments.
Glauconite - greensands
A defining characteristic for this type of minerals is the potential for perfect basal cleavage where the individual mica crystals can be split into extremely thin elastic plates.
The most well known uses of mica to the general public would be as a toothpaste ingredient and also in cosmetic products like eyeshadow.
Alloys (lithium from Lepidolite)
Aluminum production
Artificial snow
Asphalt roofing felts and shingles (protective coating and weather proofing)
Batteries (lithium from lepidolite)Other uses
Beauty products Casting (mica strainer used in producing bronze, brass and aluminum castings)
Ceiling tiles
Christmas ornaments (as a flocking materials and to provide glittering effects)
Commutators
Concrete block fillers, refractory bricks, gypsum board (reinforcing structures, fire resistance, sound absorption, corrosion protection)
Condenser Plates (mica is covered with silver to make capacitors.)
Used to produce the energy to make the camera flash work
Explosives (as an absorbant)
Foundry works, enamels, mastics and adhesives (improves physical properties, anti-sag, reduces cracking)
Glass (lithium from lepidolite)
Guided missiles
Heating elements (electrical insulation. The wire is wrapped around the mica in toasters, irons, kettles and hair driers)
Insulators (wires, toasters, irons, etc.)
Lasers (lithium from lepidolite)
Liquid level indicators (mica is unaffected by high temperature and pressure. It is used for checking boiler for liquid level and pressure of steam)
Lubricants Medication - psychiatric disorders (lithium from lepidolite)
Microwave windows
Oil well drilling (drilling mud additive to overcome loss of circulation)
Ornamental stone
Paint, textured (improves physical properties and durability, adhesion and water proofing)
Pearlescent pigments (provides lustre in paints, lipstick and other materials)
Plaster (improves acoustical properties)
Plastics (improves thermal and dielectric properties, impact strength and heat resistance)
Rocket propellants (lithium from lepidolite)
Roofing shingles
Rubber (prevents adhesion of rubber compound to the mould during vulcanisation)
Soldering irons
Spark plugs
Telephones
Television tubes (mica spacers to hold tube elements in position and insulated from one another and lithium from lepidolite)
Transistors (heat and electric insulator)
Wall-paper
Welding electrodes, cables and wires (protective coatings, and improves dielectric properties, electrical and mechanical strength)
Welding rods (lithium from lepidolite)
Well-drilling muds
Windows (kerosene lamps, and furnaces)
What mica does in toothpaste
The two main functions of mica in toothpaste is as a mild whitening abrasive and also as a shimmering colorant.
Whitening abrasive
Mica is a mineral and will be mildly abrasive which makes it a good whitening abrasive to remove extrinsic stains from the surfaces of teeth.
The way it works is similar to hydrated silica in that its mildly gritty physical characteristic allows it to mechanically abrade stains. The mild abrasiveness permits it to scrub away stains on the exterior tooth surface.
In other words, you can think of it as micro-polishing the enamel surface to remove tooth stains. That is essentially how most whitening toothpastes clean your teeth and make them whiter.
Shimmering colorant
A secondary function of adding mica to toothpaste is for its shimmering/glittering/sparkling optical properties. The addition of it will make the toothpaste sparkle and glitter thus serving as an aesthetic modulator.
In other words, this function is purely for aesthetic purposes because it makes the paste look pretty. In case you don't believe us, we've a comparison video of what a mica toothpaste looks like vs non-mica toothpastes.
Below are still photos showing you the comparison of a mica toothpastes vs 2 toothpastes without it.
It may be a little hard to see so we zoomed in and magnified the next image.
Once again, we magnified it even more! Here you can see little specks of sparkles and shimmering substances embedded within the mica-based dentifrice.
Is that convincing enough for you?
The lighting may make it a little hard to distinguish in the photos but we promise you that as soon as we dispensed the toothpaste, we immediately noticed that it was different from the usual opaque white colored pastes.
Side effects
According to the NJ Department of Health, there may be potential hazardous side effects from coming into contact, inhalation, or ingestion of mica.
Adverse effects:
Fibrosis (lung scarring)
Lung cancer
Emphysema
Coughing
Shortness of breath
Other respiratory problems.
Most of these side effects are due to inhalation of the mineral over a long period of time. There are currently no acute (short term) effects from immediate exposure but long term chronic exposure may result in these health effects.
Safety
Mica is approved by the FDA to be used as a color additive to many foods, drugs, cosmetics, and medical devices. Yes, that includes dentifrices like toothpastes. For toothpaste specific approval, you can find it at the code of federal regulations 73.1496 Mica.
However, it would behoove you to know that previously it was labeled as an air contaminant by OSHA/NIOSH with specific workplace limits.
Limit - 20 million parts per cubic foot over an 8-hour workday.
Although the most recent update on the CDC website states that the current limits are NOT in effect due to the US Circuit Court of Appeals.
OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.
Now isn't that fascinating?
Is it safe to use in toothpaste?
In our opinion, mica is safe for use in toothpaste because none of it is being swallowed. The directions/instructions for all toothpastes explicitly state that you shouldn't swallow it because you should be spitting it back out.
Overall, there should be minimal to no ingestion of this toothpaste ingredient. We may be more concerned if there was mica in food but for dentifrices, it shouldn't present as an issue.
Abrasiveness
Mica is considered a soft mineral with a 2.5-4 on Mohs scale of hardness and that means it is safe to use on enamel. The reason is because enamel has a 5 on Mohs hardness scale so it won't get scratched by it since it is harder than it.
Mineral | Mohs Hardness Scale |
|---|---|
Mica | 2.5-4 |
Hydroxyapatite (Enamel) | 5 |
In summary, enamel is harder relative to mica so it is unlikely for it to be harmed. Therefore, I wouldn't even worry about any potential enamel damage while brushing with this ingredient.
