Types of smile lines and smile shapes — low, average and high smiles explained

Key facts

• Low, average and high smile lines describe tooth and gum display
• Consonant smile arc follows the lower lip
• Flat or reverse arcs can look older
• Lopsided and gummy smiles have several possible causes
• Smile line guides gum work and number of veneers

Low, average and high smile lines

The smile line describes how much of the upper teeth and gum the upper lip reveals when you smile naturally. In a low smile line, the lip covers part of the upper front teeth, so less than about three-quarters of their height is visible and gum is not seen. In an average smile line, most or all of the front teeth show, with only the small triangles of gum between teeth visible. In a high smile line, the whole tooth plus a band of gum above it is visible; more than a few millimetres of gum is often described as a gummy smile. Most people have an average smile line, and lip lines tend to lower slightly with age.

The smile arc: consonant, flat or reverse

The smile arc is the curve formed by the edges of the upper teeth compared with the curve of the lower lip when smiling. In a consonant smile arc, the edges follow the lower lip, with the central incisors slightly longer than the teeth behind them — generally considered youthful and attractive. A flat smile arc has edges forming a straight line, often due to wear, grinding or veneers made too even, and can look older. A reverse arc, where the front teeth are shorter than the side teeth, can look aged. Restoring a consonant arc is a common goal in smile design and may involve veneers, bonding or orthodontics.

Smile shapes: flat, lopsided and gummy smiles

Other common descriptions relate to how the lips and teeth behave together. A ‘flat’ smile can mean either a flat smile arc or a smile where the lip corners do not lift much. A lopsided smile, where one side lifts more or the teeth slope, may come from lip muscle activity, tooth wear, an uneven gum line or tilt of the teeth or jaw; the cause decides whether dental treatment helps. A gummy smile shows excess gum, from excess tissue, short teeth, over-erupted front teeth, jaw growth or an active upper lip. Smile width matters too: dark spaces at the corners (buccal corridors) can make a smile look narrow.

How smile lines guide treatment

The smile line strongly influences treatment planning. With a high smile line, the gum is visible, so gum health, symmetry and the edges of any veneers or crowns are on show; gum contouring may be part of the plan and margins must be especially precise. With a low smile line, the gum margins are hidden, which can allow simpler approaches, but the tooth edges and their length relative to the lower lip become the priority. The number of teeth showing in a broad smile also guides how many veneers are needed, often six to ten per arch. Smile arc and lip symmetry guide tooth lengths so the result looks balanced.

What is an ideal smile — and assessment at Manhal

There is no single ideal: an attractive smile is one that is healthy, balanced and suited to your face, age and personality. General guides include a consonant smile arc, a midline that matches the face, harmonious tooth proportions and gum display of no more than about two to three millimetres. At Manhal Medical Center, Dr. Manhal Helfawee assesses your smile line, smile arc, tooth proportions and gum levels using photographs, video and digital scanning, then explains which options — whitening, bonding, veneers, gum contouring or alignment — fit your smile type. You receive a written plan before any treatment.

A Hollywood smile is a full smile makeover, usually combining veneers or crowns with whitening and sometimes gum reshaping. Digital smile design lets you preview proportions that suit your face before anything is changed.

Prepared by the Manhal Medical Center editorial team · Updated: 2026-10-31 · Treating specialist: Dr. Manhal Helfawee

This page is general information and does not replace a consultation. Suitability, risks and results vary between patients.