## 4 Discussion  
The results of this study highlight how recent innovations, such as Digital Smile planning, are progressively changing the dental field for the better; Ref. [25]. The photograph picturing the patient's smile modified with the 2D digital workflow, in fact, achieved the highest ratings overall. Experts in the dental field gave an average rating of 3.74, while the average rating for non-experts was 4.06. The statistical analysis showed significant differences between the answers of the two groups; the dental experts voted the 2D digital workflow wax-up as the most aesthetically pleasing; however, they were found to be more critical than non-experts. The same difference was found in the ratings of the other photographs; dental experts rated the patient's natural smile without a mock-up an average of 2.30, whereas non-experts rated it 2.56, which represents a statistically significant difference as well. Likewise, the ratings of the photograph of the smile reconstructed through the traditional workflow by these two groups of people had similar statistical differences. These differences could be due to the difference in size between the two population groups or to the differences in knowledge and competence within them. Concerning the differences between ratings given by females and males, there were no statistically significant differences, except for the photograph picturing the smile with the mock-up obtained through the traditional workflow. The results showed a higher average rating in the female group (3.38), whereas the rating in the male group was 3.15. The differences in the results were also evaluated in relation to the different age groups: for the mock-ups obtained through digital workflows, there was no statistically significant difference. The oldest age group, however, assigned the highest ratings to the patient's natural smile and the smile modified through the traditional workflow, as opposed to the youngest age group. Individuals in the 15-25 age group assigned photographs 1 and 2 average ratings of 2.37 and 3.25, while individuals in the \(>\)50 age group rated the same photographs with higher scores of 3.09 and 3.58, respectively. This difference could be due to the fact that young people are more severe in terms of aesthetics and have stricter standards of beauty [26; 27], and that older people seem to not be greatly influenced by aesthetic factors [28]. However, the up-to-date literature provides controversial data when aesthetic perception is analyzed, and this could be linked to the different weight that aesthetics has around the world and among different ages; aesthetic parameters can indeed be influenced by cultural factors, individual preferences and trends of the moment too [29; 30]. In conclusion, there was a consistent pattern in the aesthetic evaluation between all the population groups included in this survey. In order of appreciation, the pattern was: mockup obtained through Digital Smile planning, mock-up obtained through traditional workflow, mock-up obtained through 3D digital workflow and the patient's natural smile. A further possibility for planning and pre-viewing restorations is free-hand mock-ups [31]; however, the aim of this study was to assess the differences between mock-ups obtained by different workflows. Free-hand mock-up is an interesting technique that is subject to the experience and aesthetic ideal of the operator; this aspect contrasts with the purpose of this study, aiming to identify the most suitable standardizable method; because of this, it was not included in this work. From the assessment of the measurements taken with the digital caliper and collected in the tables, it is clear that the patient's teeth and gingival arches were asymmetrical and remained unvaried in the mock-up obtained from the wax-up created by the technician freehand.