The daily trimming of fingernails and toenails to make them more aesthetically attractive could be detrimental and potentially lead to serious nail conditions, says a study.
Regular poor trimming can tip the fine balance of nails, causing residual stress to occur across the entire nail, said researchers from University of Nottingham.
"This residual stress can promote a change in shape or curvature of the nail over time which, in turn, can lead to serious nail conditions," said lead researcher Cyril Rauch.
For this, the researchers focused specifically on ingrown toe nails.
When devising their equations, the researchers accounted for the strong adhesion of nails to their bed through tiny, microscopic structures.
It allows the nail to slide forwards and grow in a "ratchet-like" fashion by continuously binding and unbinding to the nail.
By also taking into account the mechanical stresses and energies associated with the nail, they came up with an overall nail shape equation.
"The equation showed that when the balance between the growth stress and adhesive stress is broken - if a nail grows too quickly or slowly, or the number of adhesive structures changes - a residual stress across the entire nail can occur, causing it to change shape over time," Rauch noticed.
The equations found that residual stress can occur in any fingernail or toenail; however, the stress is greater for nails that are larger in size and have a flatter edge which explains why ingrown toe nails predominantly occur in the big toe.
The equations also showed that bad trimming of the nails can amplify the residual stress.
"We suggest that nail beauty fanatics who trim their nails on a daily basis opt for straight or parabolic edges as otherwise they may amplify the imbalance of stresses which could lead to a number of serious conditions," Rauch advised.
The study was published in the journal Physical Biology.
