Dr Mark Hughes details the causes and diagnosis of a gummy smile and explores suitable treatment options
A gummy smile can influence great distress and a lack of confidence in many people. Treatment options traditionally come from the worlds of both dentistry and maxillofacial surgery but aesthetic procedures now offer a non-surgical approach.1 It is important, however, to know how to diagnose the source of the problem and to recognise when a multi, or interdisciplinary approach is required for best outcomes. I work with closely with my clinic’s co-owner, aesthetic practitioner Mr Benji Dhillon, so we can offer a comprehensive assessment and treatment plan for all our patients.
It is generally accepted by dentists that gum display in a full spontaneous smile of less than or equal to 2mm is aesthetically pleasing.1 For patients who have more than this, it can be distressing and responsible for an actual or perceived lack of confidence, as a display of more than 2mm of gum dispels aesthetic ideals. They will often adopt a more reserved or ‘practised’ smile to attempt to hide it. I have found that it can be a source of ridicule or bullying from a very young age. In my experience, sufferers can often appear less ‘happy’ or less ‘fun’ than others due to the development of a subconscious routine of preventing their most spontaneous smile to occur.
Psychological impact While it is often generally believed that smiling can make us feel better, the theory has never been proven in the academic literature. However, a recent study was published in the Psychological Bulletin,
where American psychologists analysed nearly 50 years of data, from more than 100 studies, each of which tried to determine whether facial expressions can affect people’s moods.2 The studies, which included more than 11,000 people worldwide, concluded that smiling does make people feel happier, while scowling makes them feel angrier, and frowning makes them feel sadder.2 This raises the most important question:
Q. When do we treat a gummy smile?
A. When it bothers the patient
A gummy smile is a highly subjective diagnosis that shows tremendous variability over medical, dental and non-dental populations. When patients identify gingival (gum) display as an area of concern, a treating practitioner has to be able to determine the aetiology prior to investigating treatment options. However, some patients do not express concern about their gum display or a desire to treat it, despite it being pointed out. The gum level is the gingiva to lip relationship. A study conducted by Dr Vincent Kokich Jr, asked a group of 300 people that included lay people (those who are not medically qualified) orthodontists and dentists what they thought, when presented with varying examples and severity of gum display. It was reported that lay people were unable to detect asymmetry until it was at 3mm, or a lateral incisor narrowing until 4mm.3 Orthodontists rated their threshold at 2mm, the strictest requirement in the study group. Surprisingly, open gum embrasure became detectable by dentists at 3mm whereas gum to lip distance was 4mm, the most lenient of the study group.3 This study demonstrates that almost everyone agreed that 2mm or less of gum tissue showing was the level where most thought the smile looked normal. Most started noticing the gum tissue at 3-4mm and thought that too much gum tissue was showing anything more than 4mm.3 Some research suggests that around 14% of women and 7% of men have excessive gingival exposure (more than 2mm) when smiling.4 However, it is most likely higher than we think, primarily due to the ability of the patient to learn how to ‘hide’ the situation. As a cosmetic dentist, it also worth explaining to my non-dental colleagues reading this article, that a gummy smile, is not necessarily unattractive, especially if the patient’s smile and teeth are aesthetically pleasing. In other words, a gummy smile is generally a far greater source of distress to patients, if their teeth are discoloured, crowed and out of proportion, shown in Figure 1. So, in my experience, often by simply correcting the smile first, the gummy smile becomes far less important.
In my experience, gummy smiles occur for a variety of reasons but most commonly it is due to a short upper lip, excessive gum tissue or small teeth, all of which are genetic. Before treatment, it’s necessary to understand exactly what causes a gummy smile. There are at least seven different causes, and if you don’t diagnose the cause correctly, you’re going to pick the wrong treatment for your patients could create an unnatural look, or worse, and from experience, prevent the patient from being able to actually smile. It’s also important to note that the improvement with injectables is temporary and must be repeated every three to six months. It is important to make the patient aware that the procedure is not ‘permanent’ and requires maintenance injections over time.
So, how else can a gummy smile be treated? The ideal target is to get somewhere under 3mm for patients who desire to change their smiles. As mentioned in Table 1, there are some indications where only dental treatment or surgery will be suitable however, for the purpose of this article, I will be focusing on non-surgical techniques involving botulinum toxin and dermal fillers. These are often popular choices because they have little to no downtime associated with them. The price is also more appealing than surgery as generally botulinum toxin costs around £350 for this procedure in the UK, whereas a gum lift procedure and dental veneers can cost up to £15,000. Studies suggest that botulinum toxin, when injected into the elevator muscles of the upper lip can be an effective method.5 A botulinum toxin treatment works by injecting the product into the upper lip elevator muscles as it paralyses them and inhibits contraction of the upper lip when smiling to prevent the gummy smile, shown in Figure 2.5 In my experience, placement in the alar fossa is most common – it usually determines the surface anatomy of levator labii superioris alaeque nasi muscle (LLSAN). I would recommend that two to three units of botulinum toxin is used per injection site. Thin lips, which would fall under the short upper lip category in our table can also contribute to the problem. They can be treated by using dermal filler to increase the volume and thus the position of the lower border of the upper lip, which helps to hide the excess gum display. However, botulinum toxins and fillers only work if the problem is in the lips, not the bone. As such, care has to be taken in diagnosis and one has to be careful not to over inject the muscles, or they
could create an unnatural look, or worse, and from experience, prevent the patient from being able to actually smile. It’s also important to note that the improvement with injectables is temporary and must be repeated every three to six months. It is important to make the patient aware that the procedure is not ‘permanent’ and requires maintenance injections over time.
Often patients present with a combination of aetiological factors and a multidisciplinary approach will provide the very best results. It is important to be able to know when to refer for advice from an experienced cosmetic dentist and vice versa. I work very closely with an aesthetic practitioner in my clinic, which I believe allows us to offer our patients the most comprehensive assessment and the most effective treatment combinations. Treatment planning for a gummy smile is one such area where we can combine our expertise. Correct diagnosis in these cases is essential and this will determine what treatment is most suitable, however generally for patients with only upper lip hypermobility, injectable treatments can be a suitable option.
1. Izraelewicz-Djebali K, Gummy Smile: orthodontic or surgical treatment?, Journal of Dentofacial Anomalies and Orthodontics, 2015 <https://www.jdao-journal.org/articles/odfen/pdf/2015/01/ odfen2015181p102.pdf>
2. Coles NA, Larsen JT, Lench HC, A meta-analysis of the facial feedback literature: Effects of facial feedback on emotional experience are small and variable, Psychological Bulletin, 2019
1. Kokich VO Jr, Kiyak HA, Shapiro PA, Comparing the perception of dentists and laypeople to altered dental esthetics, J Esthet Dent, 1999
2. Livada R, Shiloah J, Correcting Excess Gingival Display, Decisions in Dentistry, 2016 <https:// decisionsindentistry.com/article/correcting-excess-gingival-display/>
3. Suber J et al., OnabotulinumtoxinA for the treatment of a gummy smile, ResearchGate, 2014 <https://www.researchgate.net/publication/261187831_OnabotulinumtoxinA_for_the_Treatment_of_a_ Gummy_Smile>
• Levine RA, McGuire M, The diagnosis and treatment of the gummy smile, Compendium Contin Educ Dent, 1997 • Fowler P, Orthodontics and orthognathic surgery in the combined treatment of an excessively “gummy smile”, N. Z. Dent, 1999
• Lee EA, Aesthetic crown lengthening: classification, biologic rationale, and treatment planning considerations. Pract Proced Aesthet Dent, 2004
• Robbins JW, Differential diagnosis and treatment of excess gingival display, Practical periodontics and aesthetic dentistry, 1999
• Chu SJ, Karabin S, Mistry S. Short tooth syndrome: diagnosis, etiology, and treatment management. Journal of the California Dental Association, 2004
• Ezquerra F, Berrazueta MJ, Ruiz-Capillas A, Arregui JS. New approach to the gummy smile, Plastic and Reconstructive Surgery 1999
• Bolas-Colvee B, Tarazona B, Paredes-Gallardo V, Arias-De Luxan S, Relationship between perception of smile esthetics and orthodontic treatment in Spanish patients, PLOS ONE, 2018