Toxic secret of a nice smile

In babies a gummy smile is prized by all who witness it. In adults it can be the source of anxiety and grief. Now research has revealed that two simple injections into the so-called Elvis Presley muscle can help them smile along with the rest of the world.

A study of 52 people with a gummy smile – defined as any show of gum that extends more than two millimetres above the teeth during smiling – revealed that doctors have discovered a way of improving their smile with two injections of botulinium toxin rather than by resorting to surgery.

The study, reported in Plastic Reconstruction Surgery, revealed that patients were given injections in the levator labii superioris nasalis muscle – otherwise known as the Elvis muscle. This is the muscle that dilates the nostril and pulls the upper lip upwards during a smile. It is also brought into play when someone snarls, hence its renaming in honour of the king of rock'n'roll.

Patients given the injections were so happy with their new smiles that they gave the treatment an average score of 9.75 out of 10. The benefits lasted for a minimum of three months.

The researchers say the injections can also be used to treat lopsided smiles, by varying the amount of toxin injected into the muscles either side of the nose.