Golden Proportion in Maxillary Anterior Teeth Revisited
Year: 2026
Type: article
Abstract: The golden ratio is widely cited as an ideal for maxillary anterior tooth proportions, yet studies report inconsistent conformity, and prevalence figures are almost always presented without a chance baseline against which “conformity” can be judged. The objective of this work was to determine whether the central-to-lateral incisor (CI/LI) and lateral-incisor-to-canine (LI/Can) apparent-width ratios of the maxillary anterior segment converge on a pre-specified proportional tolerance zone more often than chance, and to estimate the value on which these ratios actually center. In this cross-sectional analytical study, 100 young adults (20–30 years) attending the College of Dentistry, University of Baghdad, were consecutively screened; 50 with intact, unrestored, non-rotated maxillary anterior teeth were measured from standardized frontal intraoral photographs, and 41 remained after data verification excluded 9 records with duplicated values. Apparent widths of the central incisor, lateral incisor and visible canine were measured bilaterally by a single examiner using a purpose-built, cue-free landmarking application; a ratio was classified as convergent within 1.4–1.8. Convergence was benchmarked against a chance baseline (π₀ = 22.9%) derived from a log-uniform reference distribution, and the empirical center of each ratio was estimated by bootstrap geometric mean. CI/LI (mean 1.554 ± 0.114) converged within the tolerance zone in 36/41 participants (88%; 95% CI 74–95%), far exceeding chance (p < 0.001), whereas LI/Can (mean 1.344 ± 0.201) converged in only 12/41 (29%; 95% CI 18–44%), statistically indistinguishable from chance (p = 0.211). Both ratios lay significantly below Φ (Wilcoxon p ≤ 0.001). The bootstrap geometric mean of CI/LI was 1.55 (95% CI 1.517–1.585), an interval that excludes Φ. Maxillary CI/LI proportions cluster within a bounded interval centered near 1.55 rather than at Φ, and this clustering is real rather than a chance artefact; the LI/Can relation shows no such property. Smile-design guidance should treat the golden proportion as a range-based tolerance zone rather than a fixed target and reported “conformity” rates should always be benchmarked against a chance baseline.
Source: Dentistry 3000
Authors: Yaseen Hasan Motea, Ammar Aziz Lateef
Language: English
Subfield: Orthodontics
Field: Dentistry
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7225658171
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