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Impact of facial profile on young adults’ oral health-related quality-of-life item levels: A hierarchical analysis

ABSTRACT Objective: To assess the impact of facial profile on young adults’ oral health-related quality of life (OHRQoL) item levels. Methods: A cross-sectional study was carried out with a population-based sample of 205 young adults, with a mean age of 23.1 years. The individuals answered questions about OHRQoL (OHIP-14) and self-esteem (Global Negative Self-Evaluation). The Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) was used to evaluate normative orthodontic treatment needs and define dental malocclusion clinically. Facial profile was analyzed using photographs and dichotomized into two levels: normal (straight) and altered facial profile (convex or concave). A calibrated researcher performed the clinical examination. Association between the independent variables and the outcome (OHRQoL) was established by hierarchical multiple linear regression analysis for each item level. Considering the variable of interest (facial profile), the psychological incapacity domain was the most affected item. Results: Individuals with changed facial profile had 2.47 (1.04-5.85) times higher chances of reporting impacts on psychological incapacity than those with a normal profile (p> 0.05). The association was modulated by dental malocclusion and self-esteem. Conclusions: The convex and concave facial profile showed a negative impact on the psychological aspects of young adults’ quality of life.

Impact of facial profile on young adults' oral health-related quality-of-life item levels: A hierarchical analysis

INTRODUCTION
Clinical orthodontic diagnosis frequently ignores the psychosocial conditions perceived by individuals. 1 Although the normative evaluation is essential, self-perception provides important information about the impact of malocclusion on an individual's life. [1][2][3] In this context, self-perception is related to psychosocial well-being and may impact the quality of life. 1,3,4 Furthermore, individuals with a negative perception of their esthetic appearance have lower self-esteem 2,3 and lower oral health-related quality of life (OHRQoL) 4-6 than those who consider themselves attractive. Self-esteem is determined by a set of factors including occlusal balance and an attractive facial profile. 2,3 However, the studies carried out to date are based on dental aesthetics and generally do not assess the impact of the facial profile in this context.
The impact of malocclusion on the OHRQoL is considered a controversial topic because some studies have confirmed 7 Thus, considering the hypothesis that the face is an important factor in the evaluation of aesthetic concern, this study aimed to evaluate the impact of facial profile on young adults' OHRQoL item levels. The assessment was performed on the item level analysis of OHRQoL.

STUDY DESIGN, PARTICIPANTS, AND SAMPLE SIZE
A population-based cross-sectional study was conducted involving 205 young adults. The minimum sample was calculated assuming a test power of 80%, level of significance of 5%, and an effect size of 1.8. The finite population was used by considering prevalence of 50% of OHRQoL. 3,4 The sample included young Brazilian adults of both sexes, aged between 18 and 35 years, with an average age of 23.1 years (SD 1.02).
The study included only white individuals, due to differences in facial profile between ethnicities. The evaluation was carried out by the investigator. Current or previous orthodontic The Global Negative Self-Evaluation (GSE) 14  were used as a basis for determining treatment need. For data analysis, normative orthodontic treatment need was dichotomized into IOTN-DHC grades: grades 1 to 2, without dental malocclusion or orthodontic treatment need; and grades 3 to 5, with malocclusion and orthodontic treatment need. 15 Facial profile photographs were obtained in a standardized way, considering the distance between each volunteer and the camera. The photos were taken using a SLR D7000 camera (Nikon do Brazil Ltda.), with Nikon 18-200 mm VR f/3.5-5.6G II lens (Nikon do Brazil Ltda). 16 The camera was positioned parallel to the ground on a leveled tripod. The individuals sat on a chair next to a white wall and were instructed to look straight ahead at a horizontal line in the natural position of the head 17 , and then the profile photograph was taken. This procedure was adopted for all the study participants. In the photographs, an angle of convexity of the

RESULTS
The population of this study was composed of 205 young adults with a mean age (±SD) of 23.1 ± 1.02 years. Table 1 shows the frequency of distribution relative to OHIP-14 item levels, considering the variables analyzed.
Higher frequencies were observed in the physical pain and psychological discomfort domains.  Table 2 shows the analysis of association between the independent variables and presence of impact on each item level of the OHIP-14.
Considering the variable of interest (facial profile), psychological incapacity was the item level most affected. Individuals with facial profile convex/or concave had a 2.47 (1.04-5.85) times higher chance of reporting impacts on psychological incapacity than those with straight profile.

DISCUSSION
The literature has shown the growing importance of analyzing individual perceptions related to orthodontic treatment need. 2,6,24 In the present study, clinical treatment need was evaluated by the dental health component (DHC) of the IOTN and defined the dental malocclusion. Although they are similar instruments of evaluation, 25 the IOTN is more suitable than the Dental Aesthetic Index (DAI) because it considers the functional aspects of occlusion. 26 The main differential of this study was the inclusion of facial is indicated for determining the morphology of the soft tissues of the face. 27 Reference values were considered for the Brazilian population, 21 and straight, convex, and concave profiles [20][21][22] were identified to answer the following question: What is the impact of facial profile on adults' OHRQoL?
Our results showed that individuals with a convex or concave profile were more likely to report psychological impacts on their quality of life. According to the literature, there is a preference for a straight profile that corresponds to a Class I skeletal pattern, 28 which reflects facial attractiveness. 29  item level analysis showed an association of functional and physical aspects. It is essential to highlight that the need for orthodontic treatment was studied based on the prioritization of dental criteria and that the inclusion of soft tissue analyzes will allow a better understanding of dentoskeletal problems.
In this sense, self-esteem should not be ignored. The subjective analysis of self-esteem has a direct influence on assessments involving aesthetic concern, and individuals with low self-esteem tended to report impacts on the OHRQoL. 3,10 Thus, our results showed that individuals with low self-esteem reported a negative impact on physical pain and the psychological aspects of OHRQoL.
In the same context, the gender variable was associated with a higher chance of impact on psychological discomfort. The literature has affirmed that women report greater oral health-related social and psychological impacts than men. 10, 29,30 The main difference in the findings concerned the age range; the majority of studies that have observed greater impacts on women 10,29,30 evaluated adolescents; in our study, we evaluated young adults.

Studies that investigated the impact of malocclusion on adults'
OHRQoL were based exclusively on dental indicators, such as DAI and IOTN, 3,6,7 or including the cephalic index. 2 This is the first study to include soft tissue analysis in the observational epidemiological evaluation. We evaluated faces using photographs, which provided reliability for the facial profile diagnosis. Perhaps this is the controversy in the literature; the fact that the anteroposterior Finally, the findings do not support the study hypothesis; in both the clinical and epidemiological context, there is a need for an approach to evaluating individuals' perceptions of dental and facial aspects that affect self-esteem and have significant impacts on OHRQoL item levels.

CONCLUSION
The convex and concave facial profile showed a negative impact on the psychological aspects of young adults' quality of life.