Guide
Smile Attractiveness
Five markers—alignment, exposure, symmetry, gum show, and lip frame—determine how a smile rates. Here's what each contributes and what's actually improvable.
The five smile attractiveness markers
Research and AI smile rating both evaluate these five dimensions independently:
Dental Alignment
Straightness and evenness of teeth. Severe misalignment reduces ratings; minor asymmetry has minimal effect.
Tooth-to-Lip Ratio
How much tooth is visible during the full smile. Optimal is 75–100% upper incisor visibility. Both too little and too much are penalized.
Smile Symmetry
Left-right balance of smile width and corner position. High asymmetry is visually jarring; minor asymmetry is normal and accepted.
Gum Display
Above ~3mm of gum exposure, attractiveness ratings decline linearly. Minimal gum show (0–2mm) is neutral to positive.
Lip Frame
How the lips curve and frame the teeth at peak expression. Full, well-defined lips that curve upward outperform thin or straight lip lines.
What you can actually improve
Whitening addresses tooth color (moderate evidence for attractiveness improvement). Orthodontics addresses alignment. Botox or fillers address lip frame. Botox (lip flip) and lip repositioning surgery address gummy smile. Photography also matters—smiling with your eyes (Duchenne smile) rates higher than a mouth-only smile regardless of dental quality.
Frequently asked
What makes a smile attractive?
Smile attractiveness research consistently identifies five factors: dental alignment (straightness), tooth-to-lip ratio (how much tooth shows during smile), smile symmetry, gum display (excessive gingival show—the gummy smile—reduces ratings), and the lip frame (how the lips shape around the teeth at peak expression).
Does a gummy smile affect attractiveness?
Yes—studies show attractiveness ratings begin declining when gum exposure exceeds approximately 3mm. A very small gum show (1–2mm) is neutral; excessive exposure (4mm+) is consistently rated less attractive. Gummy smile treatments range from Botox (temporary) to lip repositioning surgery (permanent).
Do straight teeth matter for attractiveness?
Alignment is one of the five factors, but not the most predictive. Studies show that confident smile frequency, symmetry, and lip frame often matter more than perfect orthodontic alignment. Severe misalignment is a negative signal; minor crowding is not significant.
What is the ideal tooth-to-lip ratio?
During a natural smile, 75–100% of the upper central incisors should be visible below the upper lip. Too little exposure reads as a 'tight' or closed-seeming smile; excessive exposure combined with high gum show reads as a gummy smile.
Keep reading
How to improve your smile
From free (technique) to costly (veneers)—ranked by cost-to-impact ratio.
How symmetric is my face?
What AI measures, what normal scores look like, and how much symmetry actually affects attractiveness.
Face symmetry and attractiveness
The research shows a modest link—here's what it actually says and what outperforms symmetry.
This page is general information about facial aesthetics terminology, not medical or cosmetic advice. Scores from our tools are AI-generated estimates for entertainment and self-reflection.