The influence of maxillary central incisor height-to-width ratio on perceived smile aesthetics

To determine the influence of varying the width-to-height ratio of maxillary central incisors on perceived smile aesthetics.

Cross-sectional study.

Postgraduate dental teaching hospital.

A posed female smile was digitally modified using Adobe Photoshop(®). Three images were created; central incisors with normal form, tooth wear and delayed apical migration. For each image the length of the teeth was altered to create a set of nine images with normal form (66% to 96% width-to-height ratios), and sets of five images with tooth wear and with delayed apical migration (78% to 96% ratios). The images in each set were ranked in order of most to least attractive by 32 dentists, 32 technicians and 32 patients.

An 82% width-to-height ratio was perceived as the most attractive for normal central incisors although there is variability in the responses. There is a definite trend towards the extremes of very long or very short teeth being less attractive. The very long central incisors, and those with tooth wear were perceived as unattractive. The patients rated fewer images from the tooth wear and delayed apical migration sets as unattractive compared to the dentists and technicians.

The width-to-height ratios perceived as most attractive correspond with the higher end of ideal ratios proposed in the dental literature (75-80% width-to-height ratio). Significant differences exist between the aesthetic perceptions of dentists, technicians and patients and there is lack of agreement within each group, in particular within the patient group. The individual variability in patient response should be taken into account during treatment planning.