Background: The objective was to determine if asymmetric facial features, nasal and chin deviations, affect the perception of attractiveness of a dental midline angulation, and if it is consistent among both dentists and laypeople. It was also analyzed if factors, such as the sex, age group of the participants and the dentist’s area of operation are relevant in their assessment. Methods: A cross-sectional study, approved by the Ethics Committee of Fernando Pessoa University. From a symmetrical facial model (SFM) image, a natural-looking asymmetrical face was created. Based on this asymmetric facial model six images were created, with different directions and degrees of inclination of the dental midline. In total, 236 laypersons and 242 dentists completed the online questionnaire where they rated the self-perception of attractiveness of the eight images (VAS scale from 0 to 10). Non-parametric comparisons (IBM© SPSS Statistics vs. 27.0, p < 0.05). Results: The results showed a significant difference in the perception of attractiveness between laypeople and dentists. This finding was consistent regarding every image, except for the SFM. The factors, sex of the people participating and dentist’s area of operation, seemed only to contribute to a significant difference in the perception when it came to the SFM. The perceived attractiveness of the images, for dentists and laypersons, did not differ by age group of the participant, apart from images 6 and 8. Conclusions: Dentists are more rigorous about dental midline inclinations than laypersons. The perception of attractiveness was affected by the age group and sex of the participants and the dentist’s area of operation.

The present study had a convenience sample with 236 laypeople and 242 dentists who completed an online questionnaire to choose the most attractive image among six pairs for comparison. Control image: symmetric (parallelism between occlusal plane (OP), commissural line (CL), and interpupillary line (IL)). Change of Control, obtaining three images with a 3-degree inclination of the labial commissures. Image A: OP parallel to IL; Image B: OP parallel to CL; Image C: OP at 1.5 degree mean angulation between IL and CL. Non-parametric comparison (IBM© SPSS Statistics vs. 27.0, p < 0.05). The “Dentists” group’s decreasing order of preference (attractiveness) of the images is: Control > A > C > B (p < 0.05). In the “Lay” group, it is: Control > A > (C not ≠ B). Dentists significantly prefer more the Control and Image A than laypeople (p < 0.001). Sex (single exception in laypeople), age, and dentist’s area of activity did not interfere in the perception of attractiveness. Dentists and laypeople preferred the Control when compared to images with CL canted. In the existence of CL inclination, the preference of the groups was the IL as a reference for OP orientation, with the mean angulation or coincident with the CL being considered less aesthetic.