There are five important properties of the natural nail that we don’t often think about. We describe our nails with words like strong, flexible, brittle, tough, and hard, but looking a little deeper into the scientific meaning of these terms can help nail technicians take better care of clients’ nails.
The resistance to scratching or denting of the nail plate’s surface.
Diamond is the hardest known substance, but is easily cut into smaller stones or faceted into a gem. Why? Diamonds are quite brittle and not particularly strong. Nail plates that become too hard also become very brittle. Nail plates that are too soft are more easily scratched or stained and have a tendency to peel or become pitted. Healthy nail plates need to be hard, but not too hard or they become more susceptible to shattering and splitting. For example, overuse of nail hardeners may cause excessive hardening and rigidity which leads to brittleness and breakage. Nail hardeners are usually best for weak, thin, flexible nails—they’re not for use on brittle or very rigid nails.
The nail plate’s ability to resist breaking under heavyloads or impacts.
A bridge must be strong to hold all the crossing cars. In this case, the cars are the “load.” Tree branches must be strong to resist the load created by heavy winds. What would happen to a tree that didn’t bend in strong winds? It snaps! Our nail plates need to be strong enough to resist the loads we put on them by picking, prying, scratching and clawing. All that we do to our natural nails is proof of their strength, but strength alone does not create a healthy nail. Steel is strong, but nails of steel would be too rigid. It’s a benefit that nail plates aren’t too strong. When the nail plate breaks, it prevents injury to the matrix area where the nail grows. Nail strength is important, but it must be balanced with flexibility.
The ability of a nail plate to bend and absorb a load or impact.
It the nail plate didn’t bend, most bumps or bangs would result in cracks, breaks or chips. Our bones emonstrate the importance of flexibility. Young children’s bones are highly flexible, but they lose flexibility with age, becoming more rigid and more likely to break. Elderly people’s bones lose most of their flexibility, become brittle and are easily broken. Don’t confuse flexibility with strength; they are quite different. Many things are very flexible, but have very little strength. Aluminum can pop tops are very flexible and after bending a few times they’ll break off. Normal nail plates are highly flexible and will bend rather than break. What factors can affect nail flexibility? Age, diet, health, prolonged or repeated exposure to harsh cleaners and solvents, excessive hand washing or moisture, and heat or cold can all affect nail flexibility.
A balance of strength and flexibility for resistance to breakage.
If strength and flexibility are in balance—the result is a tough, durable nail plate. Nylon hair combs or plastic garbage bags are examples of extremely tough, flexible materials that bend or stretch before breaking or tearing. Nails that are rigid, brittle, easily fractured or torn, are showing signs that toughness has been lost. Healthy hair and nail plates are normally tough. Wet hair can stretch up to 50 per cent of its original length without breaking. Hair has great toughness, but not as much as the nail plate! The extreme toughness of a healthy nail plate is one of its most useful properties.
Why do nails become brittle, snap or split too easily? When strength or flexibility is too far out-of-balance, then toughness is lost! Nail plates that are too flexible will lose strength. The reverse holds true; if a nail plate becomes too strong, it loses flexibility. Either way this out-of-balance nail plate has lost toughness and is more likely to break or split. Sharp breaks, cracking or fracturing are all sign of brittleness. The best way to keep nails tough is to keep their strength and flexibility in balance. You can restore some balance to brittle or overly rigid nails with daily home treatment using high-quality, penetrating nail oil that improves the nail’s flexibility and helps restore toughness. Avoid repeatedly soaking nails in water, since water dramatically increases the nail plate’s flexibility and lowers its toughness.
The result of abrasion or rubbing that erodes the nail plate’s surface.
Nail plate surfaces are worn away by files coated with abrasive particles. Most nail files have a layer of a black, crystalline mineral called silicon carbide, which is nearly as hard as diamond. On a one to ten scale, diamond hardness is ten while silicon carbide is a nine. Aluminum oxide is another abrasive used on files; it is white and a little softer with a hardness of 7.5.
That’s why an identical grit file, made using aluminum oxide, is noticeably less aggressive on the nail plate, which is only a 2.5 in hardness. If not used carefully, the more aggressive diamond and silicon carbide files can damage the much softer nail plate.
Aggressive or heavy-handed filing can quickly wear away the surface of the nail plate by scratching off too many layers. Lower grit files create larger and deeper scratches which lead to thinner and weaker nail plates. Using too much downward pressure while filing increases nail thinning and weakening. When filing the nail plate, the rule should be “do no damage!” To recap some important points, sharp breaks, cracking or fracturing are all signs of brittleness. Thin nail plates are too flexible and not very tough, so file as little as possible on the natural nail plate to avoid thinning. Regular application of a high quality, penetrating nail oil can increase flexibility and reduce brittleness. Excessive use of nail hardeners can lower flexibility and may increase brittleness.
Understanding the science of the nail plate… priceless.
This article is based on information printed in “Nail Structure & Product Chemistry”, Second Edition, Doug Schoon Thomson Delmar Learning.