Effect of Labial-lingual Inclination of Maxillary Incisors on Aesthetic Assessment for Smile Profiles with Different Chin Positions.

Abstract

Objective: To explore and visualise how different degrees of labio-lingual inclination of the maxillary incisors affect the aesthetic assessment of smiling profiles in people with various chin positions. Different perceptions from professionals and non-professionals are outlined in this study.

Methods: A profile photograph with a clear facial contour and a full smile was captured and then edited into a series of 49 smiling profile pictures, with seven variations in both chin position and maxillary incisor inclination. A MaxDiff survey was conducted to rank the photos according to the aesthetic preference of orthodontists and laypeople. The data were then evaluated using count analysis and hierarchical Bayes estimation.

Results: Upright and mild lingual inclination (0 to 5 degrees) of the maxillary incisors generally gained higher acceptance in both groups when chin protrusion was not taken into consideration, whereas the opposite was true for labial inclination. The acceptance of excessive lingual inclination (10 to 15 degrees) of the central incisor in laypeople was significantly higher than in orthodontists. Both groups suggested that as chin retrusion increases (6 mm), increasing maxillary incisor lingual inclination (10 degrees) is preferred. When chin retrusion was greater (6 mm), upright or mild lingual inclination (0 to 5 degrees) was considered acceptable by orthodontists, but greater lingual inclination (5 to 15 degrees) was also acceptable by laypeople.

Conclusion: Both labio-lingual inclination of maxillary incisors and chin position play an essential role in the aesthetic assessment of smile profiles. The ideal value for maxillary incisor inclination varies with chin position.