How to treat a second smile line with Botox and dermal filler

Some patients will visit an aesthetic clinic with concerns about a second smile line – a horizontal crease above their top lip – some want to embrace it, but others want to erase it. Understanding the indications for treatment, patient selection, and a treatment plan is key to avoiding the wrong outcome.

In this blog, Dr Tim Pearce will explore the second smile line and the anatomy involved, looking at who to treat and who not to treat, as well as how to treat it and why it can be quite tricky; he will also explain why eliminating it may inadvertently alter the appearance of the upper lip, making it appear smaller, or even disrupt familiar facial expressions that are crucial for interpersonal communication.

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What is a second smile line?

The ‘second smile’ is a curious one, and you might be forgiven for picturing something altogether odd when you visualise it! However, it is not a smile as such but quite a subtle extra line above the top lip which seems to upset a minority of patients.

Most of the lines that patients complain about during their consultation are vertical lip lines, including requesting treatment for oral commissures, and melolabial folds or marionette lines, but there are a minority of patients who present with a horizontal lip crease or second smile line.

This lip crease troubles some, whereas others find it quite endearing, and they like it and want to keep it. Our job, as aesthetic clinicians is to try and identify who will benefit from treatment and who will not so we can ensure we get the best result, both psychosocially and aesthetically.

The anatomy that causes the formation of a second smile line

A horizontal crease above the top lip is caused by the muscles around the nose and the upper lip and the anatomy can be quite variable between different patients notes Dr Tim.

For example, in some patients, it will be caused predominantly by the action of the depressor septi nasi muscle and its connections in that area of the face. For others, however, it may be related to the orbicularis oris. Dr Tim also believes that the levator labii superioris alaeque nasi plays a role in its formation for some patients. For many, it can be any of the lip elevator muscles.

He explains that this is particularly true when a nose is quite strong. You may often notice a stronger nose with good lip elevation which is very likely to lead to the development of a horizontal crease, meaning all the lip elevators may be playing a role in its formation – zygomaticus major, zygomaticus minor, levator labii, levator labii superioris alaeque nasi, and the depressor septi nasi muscles. Therefore, it could be very difficult to treat a second smile line because you cannot neutralise all those muscles (with botulinum toxin).

Patient selection for treating a second smile line

The ideal patient for treatment is someone with a second smile line in the middle of the spectrum.

If they present with very powerful lip elevation and a strong nose, you are unlikely to be able to stop that with Botox® and dermal filler, explains Dr Tim. However, if it is milder, the crease is smaller, and the muscles involved are a little bit on the weaker side, but still enough to cause a crease, there is more likelihood of improving the situation.

Of course, your patient may not dislike the crease and you must establish whether it is a problem for them, or not, during the consultation because removing something that they like is never a good thing to do as an aesthetic clinician.

There can be downsides to treating a second smile crease line. It might result in less upper lip show for the individual, reducing the action where the top lip rotates and rolls upwards as they smile, normally making their lips bigger. Although treatment may remove the crease, the loss of the top lip show would be a good reason not to treat the patient.

How to treat a horizontal crease line above the lip

You can approach treating a second smile line above the lip in multiple different ways and with different modalities informs Dr Tim. Like any crease in the face, it is vital to understand that it is a combination of what is happening to the tissue and the effects of the muscle on the tissue, he explains.

As a treatment plan, we would usually think to first treat the muscles that are causing the crease. This means considering how to relax muscles in certain parts of the face without causing disharmony, to create a beautiful smile without the distraction of the line that is bothering the patient. This can be achieved with very small amounts of botulinum toxin, but it can also be done, in some patients, with dermal filler.

The dermal filler will act as a mechanical block on the muscle; as you add volume, the muscle must contract much harder against the dermal filler. This is also a common way to treat a gummy smile. In many cases, it can be a little bit easier to create a harmonious smile with this approach because mechanical blocking is gentler. It is particularly useful when the patient already has some volume loss. If you have a patient with a horizontal lip crease alongside a nasolabial fold and volume loss, you should be considering some dermal filler within the treatment plan. Starting with treatment of the nasolabial folds will decrease the lip elevator activity, you can also do this with botulinum toxin, followed by strengthening the lip with dermal filler.

Dr Tim offers a note of caution that if you volumise a lip, it can have the opposite effect on upper lip creasing. This is notably visible in patients who have unfortunately been overtreated in the lips and who develop new creases because of the impact of the placement of large volumes of dermal filler next to tissue that has not got any additional strength. Therefore, as their strong lip rises, it compresses tissue above and creates an upper lip line crease and more commonly vertical creases (creating a duckbill shape) where the cheek tissue meets with the upper lip. Read up on how to avoid, prevent and treat lip filler migration and the causes of the classic duck lip.

To ensure we create the opposite outcome, it is worth considering alternatives within your treatment approach.

For example, the philtrum can be treated in some patients to relieve a horizontal line. The philtral columns often become disrupted as the upper lip rises – the tissue bends and the philtral columns are dissected by the crease. By directly treating the philtral columns, some benefits can be gained for some patients. It will not achieve a powerful result and works better when performed in conjunction with other treatments, urges Dr Tim, but it can soften a second smile line in some patients.

It is certainly a better course of action for most patients than directly filling the crease itself. If you treat the horizontal line with dermal filler, it can create various disharmonies, he warns. For example, such treatment can make the white lip compete with the pink lip; a projecting white lip next to a relatively smaller pink lip will not look natural.

This is a less is more treatment area – you can add tiny amounts of a low-viscosity dermal filler product to the crease which might soften the line enough in some patients, he explains, but you must use caution, or you will alter the shape of the area and create a Homer Simpson or simian shape to the mouth area. Patient selection is vital and attempting this may only be appropriate in those with very small lines to avoid this outcome.

Dr Tim’s take-home message is, to be honest with your patients, select who to treat very carefully, choose those with smaller horizontal creases or minimal second smile lines, who are acutely bothered by it, and explain to patients with deep lines, strong noses, and strong elevator muscles that it is going to be very difficult to soften the line without causing disharmony and adverse outcomes. Be prepared to say no to such patients.

Have you any top tips for treating this area? Dr Tim is always keen to hear about the experiences of his followers; if you have any tips to share, case studies to discuss, or questions for him, you can find Dr Tim Pearce on Instagram.

If you want to learn more in-depth treatment plans to treat smile lines and upskill your knowledge of anatomy, make sure you get on the waiting list for Dr Tim Pearce’s Pro Injector membership.

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Aesthetics Mastery Show

How to treat a second smile line with Botox & Filler

Dr Tim says:

“In this episode, I discuss the indications & treatment plans to erase the “second smile line.”

This is an interesting line to treat. While some patients embrace their second smile, others seek to erase it.

However, patient selection is key here. Eliminating it may inadvertently alter the appearance of the upper lip to appear smaller or even disrupt familiar facial expressions crucial for interpersonal communication.”

Watch the full Aesthetics Mastery Show here.

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