The Golden Ratio ($1.618) in mathematics is a classic guideline in aesthetic dentistry for determining the ratio of the width of the upper front incisor to the width of the lateral incisor, and the ratio of the width of the lateral incisor to the frontal portion of the canine tooth. However, in diastema closure or smile design cases, this ratio cannot be applied as a strict rule to every patient; because the patient’s facial width, biotype (dolichocephalic or brachycephalic facial structure), distance between the eyes, and nasal base width require modification of these ratios. Sometimes, instead of the golden ratio, the dentist applies the principles of “Characterized Aesthetics” or “Soft Symmetry” by basing it on the aspect ratio within the teeth themselves ($75-$80% ideal aspect ratio). Otherwise, applying the golden ratio as a single, stereotypical model to every patient can lead to an artificial appearance that does not match the patient’s facial characteristics.
