The Differences between Dentist’s and Non-Dentist’s Perceptions of Facial Attractiveness

Orthodontics plays a role in an individual’s appearance which can affect the perception of others that can vary greatly depending on their educational and social economic background. Objective: To determine if there were differences between dentist’s and non-dentist’s perceptions on facial attractiveness with normal occlusion and various types of malocclusions in Indonesian population. Methods: A cross sectional study was conducted on 80 dentists and 80 non-dentists aged 23-49 years old. The perceptions differences between groups were assessed using visual analogue scale on ten photographs for each gender that have been digitally manipulated. Mann Whitney test was used to analyze the differences. Results: Normal occlusion is the most attractive condition for dentists and non-dentists. There are significant differences between dentist’s and non-dentist’s perceptions of facial attractiveness showing normal occlusion, increased overjet, increased overbite, reduced overjet, reduced overbite, mild crowding, open bite, and reversed overjet malocclusions (p<0.05). Whilst both groups agreed (p>0.05) that severe and moderate crowding were the least attractive malocclusion. Conclusion: Regarding the facial attractiveness, dentist’s and non-dentist’s perceptions are significantly different for most malocclusion types. However, there is an agreement that severe and moderate crowding are the most disturbing malocclusion that have a considerable effect on facial attractiveness.


INTRODUCTION
In the nineteenth century, malocclusion was thought to represent an abnormal state, but by the mid-twentieth century orthodontists questioned whether malocclusion was really a disfigurement or a malformation. In the twentyfirst century, we recognize that malocclusion is rarely a disfigurement, can occasionally be a malformation, but most often simply represents anatomical variation. In many cases, orthodontic treatment is used to improve dentofacial appearance and function to achieve a state that is considered "normal" and approach the theoretical ideal. Today, the goal of orthodontic treatment is often associated with an increase in the social life and quality of life of individuals. In an individual with Class I, spacing or mild crowding, which previously said was within normal limits and not needing orthodontic treatment, can now choose to obtain more than the normal state and achieve perfection. Orthodontic treatment is currently considered to play a role in providing psychosocial impression to display social welfare and improvement in quality of life. 1 Some studies showed that an individual's appearance can affect the perception of others. People with more attractive faces are judged more positively, more outgoing, socially competent and powerful, sexually responsive, intelligent, and healthy. 2 Children aged 8 to 10 year old with a pleasant dental alignment are seen by their peer to be happier, more loved by their parents, better mannered, more honest, and more altruistic. 3 Malocclusion has a psychological impact in adolescents and this impact increases with the severity of malocclusion. 4 A study in Michigan showed that malocclusions affect ratings of attractiveness,  intelligence, and personality, as well as behavioral intentions to interact with others. 5 Positive or negative perceptions were influenced by environment, media, and culture in which individuals live. 6,7 Perceptions of attractiveness by dentists and non-dentists would be different because of their different background knowledge and expectation. It was previously showed that dental professionals and lay people have different smile esthetics perceptions. 8 Different results were shown in several studies. 9,10 They mentioned that there was no difference between a professional and a lay person's perception of facial attractiveness. A previous study showed that there was no significant difference in perception of orthodontists and general practitioners. 11 The above studies showed that there were inconsistent results about the effect of various malocclusion types towards dentist's and non-dentist's perceptions of facial attractiveness. The objective of this study is to determine the differences between dentist's and non-dentist's perceptions of facial attractiveness with various malocclusions particularly in Indonesian population.

METHODS
A cross sectional study was conducted to assess 160 subjects with age range between 23-49 years old. Research subjects consist of 80 dentists working at Faculty of Dentistry Trisakti University or Suku Dinas Kesehatan Jakarta Barat and 80 non-dentists with occupation as lecturers at Faculty of Law and Faculty of Economic, Trisakti University. The non-dentist samples were taken from the same level of education and social economic status to ensure their homogeneity. Ethical clearance for this research was issued by Faculty of Dentistry Trisakti University Research Ethic Commission. The entire research subjects were given the preliminary information about this research and signed an informed consent if they agree to participate in this study.
The photos of male and female faces of average attractiveness were manipulated to depicted persons with a normal occlusion and nine types of malocclusion using Adobe Photoshop CS5 Extended Program, version 12.0 x64 (Adobe System Inc., USA). This design ensured every aspect of the photos characteristics other than malocclusion types were remains constant.
The differences between dentist's and non-dentist's perceptions were assessed by every subjects in each group giving scores on ten males ( Figure 1) and ten females ( Figure 2) models gray scale facial photographs that have been digitally manipulated, showing normal occlusion and nine types of malocclusion.
Perception of facial attractiveness was measured by visual analogue scale (VAS) scoring 0-10. Correlation test was used to assess the inter and intra reliability of the questionnaires using ten randomly selected subjects for both dentists and non-dentists groups. The photographs as part of the questionnaires were scored twice at seven days apart. Kolmolgorov-Smirnov was used for normality test. Subsequently, Mann Whitney test was used to analyze the differences between dentist's and non-dentist's perceptions of facial attractiveness with various types of malocclusions.

RESULTS
The intra observer reliability of the questionnaire by means of correlation test showed good correlation (r value 0.764-0.998). Kolmogorov-Smirnov normality test indicated that all data from both dentists and non-dentists group for all types of malocclusion is not normally distributed (p <0.05). Therefore, the Mann Whitney non-parametric test was chosen to test the relationship between malocclusion and ranks of attractiveness between dentists and non-dentists. The test found statistically significant different between dentists and non-dentists in their perception of attractiveness as influenced by malocclusion. The test also found that the most attractive facial appearance was the face with normal occlusion, followed by increased overjet, increased overbite, reduced overjet, reduced overbite, mild crowding, open bite, reversed overjet, moderate crowding, and severe crowding ( Table 1).
The perceptions of facial attractiveness showing various malocclusions were significantly different between dentists and non-dentists for normal occlusion, increased overjet, increased overbite, reduced overjet, reduced overbite, mild crowding, open bite and reversed overjet. There were no significant differences between dentist's and non-dentist's perceptions on facial attractiveness showing severe crowding and moderate crowding ( Table 2).

DISCUSSION
Previous studies showed that different malocclusions can affect person perceptions. 4,5 There was contradictory agreement on perception of facial attractiveness between dental professionals and lay-persons. [8][9][10] We analyzed whether dentists and non-dentists perceived facial attractiveness differently depending on the type of occlusion exhibited.
Normal occlusion was the most attractive condition for dentists and non-dentists. The results were similar to a study before, photos showing the target persons with normal occlusion were evaluated as most attractive, most intelligent, most agreeable, most extraverted, and very conscientious. 5 Although the malocclusion rank of attractiveness between dentists and non-dentists were relatively the same, there were some discrepancies detected. Dentists tend to give higher scores for normal and increased overjet, and lower scores for open bite and reversed overjet. It showed that dentists were more sensitive in detecting various malocclusions from photographs. 13 Severe crowding and moderate crowding were the least attractive malocclusion. There were no differences between dentist's and non-dentist's perceptions of facial attractiveness showing severe crowding and moderate crowding. The results were consistent with a previous study which stated that crowding created the worst impression and were among the most dislike malocclusion traits. People with crowding trait were easily noticed for their compromised aesthetics and had to face discrimination. 12 This study showed that perception of facial attractiveness showing different type of malocclusions were different between dentists and non-dentists. Thus, it is highly recommended to line up expectations between provider and patient prior to treatment.

CONCLUSION
Regarding the facial attractiveness, dentists and non-dentists perceptions particularly in Indonesian population are significantly different for most of the malocclusion types. However, there is an agreement that severe and moderate crowding are the type of malocclusion that showed considerable effect on facial attractiveness. Differences in perception of facial attractiveness were found to be influenced by educational background and specific professional training. Further study needs to be conducted involving orthodontists.