Influence of dental midline deviation with respect to facial flow line on smile esthetics-A cross-sectional study.

BACKGROUND/OBJECTIVE: A contemporary concept states that dental midline deviation towards the direction of facial flow line (FFL) can mask the compromised smile esthetics. This study aimed to identify a range of midline deviations that can be perceived towards or away from the FFL influencing smile esthetics. MATERIALS AND METHODS: A cross-sectional study was conducted using a frontal smile photograph of an adult female. The photograph was altered on Adobe Photoshop software into six different photographs by deviating the dental midlines towards and away from the FFL. A constant deviation of chin towards the left side was incorporated in all the photographs. Forty-three laypersons (LP) and dental professionals (DPs) evaluated those photographs. Independent t-test was used to compare the perception of dental midline deviation between LP and DPs. Simple linear regression was run to identify the factors associated with the scoring. RESULTS: A statistically significant difference was observed for picture two with 4 mm towards FFL in the perception of midline deviation between LP and DPs. LP could not perceive the midline deviations up to 4 mm while DPs were able to perceive deviations above 2 mm. The greater the age the better the scores were and female raters had a greater inclination towards poor scores. CONCLUSIONS: From 2 to 4 mm of midline deviation towards the FFL can be tolerated by LP and DPs. CLINICAL SIGNIFICANCE: These findings underscore the importance of considering facial symmetry in orthodontic and cosmetic dental treatments to optimize smile esthetics.

Facial flow line and its effect on dental midline deviation on a female subject in an Asian population - A cross-sectional study.

INTRODUCTION: This study aims to understand the relationship between midline deviations and the inherent asymmetry that can be observed in a human face. MATERIALS AND METHODS: A cross-sectional study was conducted using a frontal smile photograph of a female which was altered on Adobe Photoshop software version 23.0 into eight different photographs by deviating the dental midlines by 2 mm, 4 mm, and 6 mm towards and away from the facial flow line (FFL). 4 mm of chin deviation was incorporated in all the pictures except for the first picture in which the midline and chin were kept symmetric. Orthodontic residents evaluated those photographs on an interrupted visual analogue scale (VAS) with 0 being the least attractive and 10 being the most. Simple linear regression was applied to observe factors associated with VAS score. RESULTS: Highest score was observed for picture with midline and chin on (MLCon) with a score of 9.4 ± 0.7, followed by picture with midline on and chin deviated (MLon) 8.7 ± 0.8. The deviations towards green zone received higher scores in comparison to deviations towards red zone. Linear regression revealed highly statistically significant differences between the constant and the rest of the pictures. CONCLUSIONS: The formation of green and red zones by the FFL influences the perception of midline deviation as judged by orthodontic residents. Midline when deviated towards the green zone, was judged to be more aesthetic than when shifted towards the red zones.