Role of initial facial attractiveness in the perceived aesthetic outcome of convex profile treatment

Introduction

Skeletal and dental imbalances are frequently observed both in the general population and among individuals seeking orthodontic or orthognathic treatment (Josefsson, Bjerklin & Lindsten, 2007). Early diagnosis of facial skeletal problems, before the pubertal growth spurt allows for growth modification strategies (Giuntini, McNamara & Franchi, 2023). Alternative treatment plans may aim at dentoalveolar or skeletal compensation with orthodontic treatment or minor surgical interventions, respectively, or at correction of the skeletal problem with major orthognathic surgery. The latter is nowadays considered a routine treatment, although it is occasionally related to complications and patients’ refrain from treatment (Hågensli, Stenvik & Espeland, 2014; Agbaje, Luyten & Politis, 2018). Growth modification is a minimally invasive, standard procedure; however, its effectiveness in significantly enhancing facial aesthetics at rest remains controversial (Koretsi et al., 2015; Zymperdikas et al., 2016; Tsiouli et al., 2017; Zouloumi et al., 2019). Unfortunately, there is no clear boundary between these treatment indications, and the choice is largely based on the perceived patient’s needs, in addition to the clinician’s experience and convictions, as well as the importance attributed to the dental or skeletal elements of the anomaly. Nowadays, machine learning models are rapidly evolving to aid decision-making (Du et al., 2024), but the baseline information and data required to treat these models are still deficient.

Orthognathic surgery improves several aspects of the patients’ quality of life. While several parameters may determine the treatment efficacy, i.e., improvements in dental function and esthetics, temporomandibular joint disorders/muscle pain or periodontal condition, social and aesthetic aspects of treatment have a profound impact (Schaefer et al., 2024). Moreover, the improvement in facial esthetics is the main reason for which patients with dentofacial deformities seek treatment and also affects largely patient satisfaction (Pachêco-Pereira et al., 2015, 2016). This seem perfectly reasonable when considering the high impact of facial attractiveness in several fundamental life outcomes (Little, Jones & DeBruine, 2011).

Substantive research has been undertaken on the perceived treatment outcomes of convex profile individuals, primarily involving the evaluation of pre- and post-treatment photographs by assessors of diverse scientific background, age, and gender (Zouloumi et al., 2019; Psomiadis et al., 2023; Conville, Benson & Flett, 2024). However, few studies comparatively evaluated orthodontics-only vs. surgical patients using actual patient photos (Proffit, Phillips & Douvartzidis, 1992; Shell & Woods, 2003; Psomiadis et al., 2023, 2025). In an earlier attempt, orthodontists and maxillofacial surgeons rated the esthetic changes from frontal and profile photographs. Orthodontics-only patients received higher pre-treatment mean rating, which remained unchanged after treatment. Surgical patients had lower pre-treatment ratings, which improved post-treatment but remained below those of orthodontics-only patients (Proffit, Phillips & Douvartzidis, 1992). However, specialists’ groups may be more generous with their improvement ratings compared to non-specialists (Ng et al., 2013; Gkantidis et al., 2013; Zouloumi et al., 2019; Kalin, Iskender & Kuitert, 2021). A study comparing aesthetic outcomes in adult Class II patients treated with orthognathic surgery and adolescents treated with growth modification found no significant differences in pre- and post-treatment scores or overall improvement. In this study, a mixed panel of raters assessed simultaneously presented frontal and lateral facial photographs, with the treatment status arranged randomly (Shell & Woods, 2003). It can be argued here that the compared groups were not similar in terms of age, and thus of dentofacial characteristics, since the adolescent patients would express their inherent growth potential towards altering facial appearance, even without treatment (Koretsi et al., 2015; Zymperdikas et al., 2016). A recent study on orthognathic surgery patients showed notable improvements in facial appearance, with an approximate 20% enhancement in actual profile photos, in contrast to the lack of effects seen with camouflage orthodontic treatment. These improvements were consistently perceived by various groups of assessors (Psomiadis et al., 2023) and were retained when the overall facial appearance was assessed in another study (Psomiadis et al., 2025).

The aforementioned studies provide conflicting evidence attributed to different methodologies and several confounding factors. Post-treatment facial attractiveness is the primary outcome, but pre-treatment attractiveness might also influence decision-making and perceived treatment benefits (Proffit, Phillips & Douvartzidis, 1992; Burk et al., 2022a; Farshidnia et al., 2023). While prior studies linked initial dentofacial severity (Shelly et al., 2000; Tsang et al., 2009) and distinct facial features, such as the nose (Cankaya, Celebi & Bicakci, 2019), to treatment perception, direct evidence on facial attractiveness influencing perceived changes remains lacking. We hypothesize that patients with higher initial facial attractiveness may experience fewer perceived changes post-treatment compared to those with lower attractiveness. To test this, we analyzed existing data on perceived facial changes in convex profile patients who underwent orthognathic or orthodontic treatment (Psomiadis et al., 2023, 2025), in combination with newly collected pre-treatment attractiveness ratings for the same individuals.

Materials and Methods

The study belongs to a series of a large project, parts of which have been published in previous reports (Psomiadis et al., 2023, 2025). Therefore, certain methodological details are repeated here to allow full comprehension of the present study by the readers. The study protocol received approval from the Research Ethics Committee of the Dental School at the National and Kapodistrian University of Athens, Greece, prior to its initiation (Approval Date: 22.06.2018, Protocol Number: 361). Written informed consent was obtained from all participants, permitting the use of their data for research purposes.

Facial photographs

Originally, the photographs were obtained with the camera positioned at a standardized distance of 1.2 to 1.5 m from the subject’s face. Each image was edited to ensure uniform characteristics, namely a white background with uniform brightness and contrast, and standardized vertical facial dimensions (Version 22.0.1; Adobe Photoshop, San Jose, CA, USA, Adobe Systems). The Nasion–Menton distance was consistently set at 5 cm to eliminate size as a confounding factor in the assessments. Distinctive marks (e.g., moles, scars) and external elements (e.g., earrings, tattoos) were removed as well.

As published previously, following image adjustment, a configuration of four images per patient, consisting of pre- and post-treatment profile and frontal facial photos, was set in a landscape-oriented A4 size page (Psomiadis et al., 2023). A similar set of only facial profile photos was also created (Psomiadis et al., 2025). Both aforementioned sets were used to rate changes in facial appearance and the outcomes have been previously published (Psomiadis et al., 2023, 2025). For this study, patient images were displayed as shown in Fig. 1, to assess facial attractiveness.

Questionnaire fulfillment

The questionnaires used to assess changes in overall facial and profile appearance, along with the corresponding data reanalyzed in this study, were previously published (Psomiadis et al., 2023, 2025). For the evaluation of facial and profile attractiveness, each rater sequentially assessed 12 sets of photographs (Fig. 1) using a validated (Tsiouli et al., 2017; Zouloumi et al., 2019) printed questionnaire, which included a single question and a 100 mm visual analog scale (VAS) (Fig. 2). A total of 3,600 such questionnaires were administered by two calibrated researchers in a quiet room, with assessments conducted under discreet supervision.

Results

Facial attractiveness outcome

Interrater agreement on facial attractiveness ratings, both overall and within each treatment group, ranged from good to excellent across all assessments (ICC > 0.80, Table 1, Fig. 3). Consistent variances of all dependent variables were detected across groups (Levene’s test, p > 0.05).

Table 1:

Interrater agreement of VAS facial attractiveness ratings among groups of raters tested through the intraclass correlation coefficient (ICC; two-way mixed model, absolute agreement, results regarding average measures).

Treatment group	Frontal & Profile	Profile
Total	0.88 (0.79, 0.93)	0.90 (0.81, 0.95)
Camouflage	0.90 (0.80, 0.96)	0.91 (0.80, 0.96)
Surgery	0.80 (0.59, 0.92)	0.88 (0.70, 0.96)

DOI: 10.7717/peerj.19997/table-1

Considering overall facial attractiveness, there were significant differences between the treatment groups at pre-treatment, without significant effects of patient’s sex, rater group, or any interaction on the outcomes (Table 2). The raters assessed the overall facial attractiveness at lower than average levels (mean: 36.1; 95% CI [33.7–38.5]), with patients treated exclusively by orthodontics found significantly more attractive than patients that received surgery (mean: 40.2; 95% CI [36.9–43.6] vs mean: 32.0; 95% CI [28.6–35.3], respectively) (mean difference: 8.2; 95% CI [3.5–13.0]; p < 0.001). Female patients were rated as slightly less attractive, but the differences from male patients were not statistically significant (mean difference: −3.6; 95% CI [−8.4 to 1.1]; p = 0.129). Differences between rater groups were small and non-significant, apart from one comparison between orthodontists and patients, with the latter providing slightly more positive assessments (mean difference: −7.9; 95% CI [−14.6 to −1.2]; p = 0.021) (Tables S1 and S2, Fig. 3B).

Table 2:

Results of the ANOVAS testing the effect of patient’s sex, rater type, and treatment group on the facial and the facial profile attractiveness at pre-treatment condition.

Dependent variable	Factor	df	F	Sig.
Facial profile attractivenessa	Treatment group	1	14.4	<0.001
	Sex	1	1.55	0.215
	Rater type	1	3.71	0.013
	Treatment group * Sex	1	0.50	0.483
	Treatment group * Rater type	3	0.66	0.579
	Sex * Rater type	3	0.55	0.651
	Treatment group * Sex * Rater type	3	0.06	0.982
Facial attractivenessb	Treatment group	1	11.87	<0.001
	Sex	1	2.33	0.129
	Rater type	1	1.86	0.139
	Treatment group * Sex	1	0.27	0.604
	Treatment group * Rater type	3	0.21	0.886
	Sex * Rater type	3	0.05	0.984
	Treatment group * Sex * Rater type	3	0.35	0.792

DOI: 10.7717/peerj.19997/table-2

Notes:

a R Squared = 0.21 (Adjusted R Squared = 0.11).

b R Squared = 0.15 (Adjusted R Squared = 0.05).

df, degrees of freedom; F, F-value; Sig., Significance shown as p-values.

Regarding the facial profile attractiveness, significant between-group differences were evident at pre-treatment, without significant effects of patient’s sex or any interaction on the outcomes (Table 2). The facial profile attractiveness was rated at lower than average levels (mean: 37.7; 95% CI [35.5–40.0]), with patients treated exclusively by orthodontics found significantly more attractive than patients that received surgery (mean: 42.1; 95% CI [38.9–45.3] vs. mean: 33.4; 95% CI [30.2–36.6], respectively) (mean difference: 8.7; 95% CI [4.2–13.3]; p < 0.001). Female patients were rated as slightly less attractive than male patients, but not statistically different (mean difference: −2.9; 95% CI [−7.4 to 1.7]; p = 0.215). The only significant differences between rater groups were that patients’ ratings were significantly more positive than that of both specialists’ groups, but remained below average attractiveness (Tables S1 and S2, Fig. 3A).

Discussion

This study examined the impact of pre-treatment facial attractiveness of convex profile patients with increased overjet on perceived changes in facial appearance, comparing outcomes from orthodontic camouflage vs. combined orthognathic and orthodontic treatment. The findings suggested that patients with lower pre-treatment facial attractiveness experience greater perceived improvement in appearance with the combined orthognathic and orthodontic treatment compared to those with higher initial attractiveness. Raters assessed the pre-treatment profile as well as the overall facial attractiveness of convex profile individuals at below average levels (36 and 38/100 VAS units, respectively), with minimal differences between rater types. This confirms the esthetic disturbance caused by the Class II facial configuration and reflects the associated treatment need (Pachêco-Pereira et al., 2015, 2016; Gabriele et al., 2024). Despite the pre-treatment group similarity indicated by standard dental and facial soft-tissue measurements, the initial profile and the overall facial attractiveness of patients treated with orthognathic/orthodontic treatment was rated 8 and 9/100 VAS units lower than that of orthodontics-only patients, respectively. This, along with the confirmation of our study hypothesis, highlights the need to control for the facial attractiveness factor when assessing the perceived treatment effects on facial appearance. This study confirmed the significant positive effects of combined orthognathic and orthodontic treatment on the profile and overall facial appearance of convex profile patients, with little to no improvement observed in cases treated with orthodontics alone, after controlling for initial facial attractiveness. This solidifies our previous findings that did not account for this factor (Psomiadis et al., 2023, 2025), and aids the decision making process, by indicating an enhanced benefit from treatment in cases of reduced initial facial attractiveness. The latter factor had a similar impact on the outcomes of both treatment types.

Taken all the above together, as well as the substantial evidence on the impact of facial appearance on several important life outcomes (Little, Jones & DeBruine, 2011; Kanavakis et al., 2021; Conville, Benson & Flett, 2024), it becomes apparent that convex profile patients with increased overjet and significantly reduced facial attractiveness should be oriented towards the combined orthodontic/orthognathic surgery approach. Under this prism, female patients might have slightly higher treatment need, since they were consistently rated as marginally less attractive that their male counterparts. However, given that this approach involves major surgery, patients should be thoroughly informed about the associated risks and potential morbidity (Hågensli, Stenvik & Espeland, 2014; Friscia et al., 2017; Agbaje, Luyten & Politis, 2018; Almasri et al., 2024). A less invasive alternative may be orthognathic camouflage procedures, which are not associated with the same level of morbidity or prolonged recovery as conventional orthognathic surgery (Burk et al., 2022b). This intermediate approach was not examined in the present study and warrants consideration in future research.

The digital photographs that were used for this comparison is a reproducible and valid tool for assessing dental and facial attractiveness (Todorov, Pakrashi & Oosterhof, 2009), and therefore, the most common method for this assessment. Slightly modified, entire facial photos (Tauk et al., 2016) of pre- and post-treatment conditions were presented simultaneously to the raters at random treatment status order and without disclosing any information to the raters (Ng et al., 2013). Through this approach, and by asking to assess changes in facial appearance, we aimed to minimize the effects of several factors that affect facial appearance judgments (Little, Jones & DeBruine, 2011; Kanavakis et al., 2021; Gabriele et al., 2024), while presenting realistic images to the raters (Hockley et al., 2012; Sari-Rieger & Rustemeyer, 2015). Thus, the evaluations concerned primarily changes in facial morphology due to the treatments being tested, without guiding the raters towards noticing any specific element. We believe this approach reduces the impact of confounding variables, thereby enhancing the ability to identify treatment effectiveness within the framework of personalized outcomes.

In the present sample of Class II patients, the pre-treatment facial attractiveness had a significant effect on the perceived changes in facial appearance post-treatment. The higher the pre-treatment facial attractiveness, the lower the potential improvement in facial appearance. This is in agreement with findings from the literature regarding orthognathic surgery patients, not only in terms of outcome assessment (Proffit, Phillips & Douvartzidis, 1992; Mihalik, Proffit & Phillips, 2003; Raposo et al., 2018), but also in terms of patient satisfaction and decision to seek treatment (Vargo, Gladwin & Ngan, 2003; Pachêco-Pereira et al., 2016). Previous studies also suggested that the chances of significant improvement in facial appearance of convex profile patients following orthognathic surgery are higher when the initial sagittal skeletal discrepancy surpasses a cephalometric threshold (Shelly et al., 2000; Tsang et al., 2009). However, it should also be considered that larger changes may carry a greater risk of relapse, which might lessen these effects over the long term (Mihalik, Proffit & Phillips, 2003). Facial attractiveness levels have also been shown to significantly influence the perceived benefits of smile enhancement following orthodontic treatment, with a greater positive impact of posttreatment smile in less attractive females (Farshidnia et al., 2023). The facial outcome is also mediated by other facial features, such as the nose (Raposo et al., 2018; Cankaya, Celebi & Bicakci, 2019). Therefore, substantial evidence that facial attractiveness has a key role in decision making and impacts the perceived outcomes related to patient satisfaction was already available. The present study directly assessed this factor and quantified its impact, solidifying the previous evidence. It also confirmed that the substantial benefits in facial appearance detected after combined orthodontic/orthognathic surgery treatment remain clearly superior than that of the orthodontic treatment alone after controlling for the initial facial attractiveness factor. Minimal changes were demonstrated in facial appearance for those patients who exclusively received orthodontic treatment. Therefore, it can be argued that the orthognathic surgery approach should be the first treatment of choice in all convex profile individuals that seek improvement of their facial appearance. The facial attractiveness factor should be considered in decision making, among several other factors, as a factor that mediates treatment benefits and should be communicated to patients as such. The amount of this effect has been determined at 0.3/100 VAS units decrease in the perceived changes in facial appearance for every 1 unit increase in overall facial attractiveness. The corresponding effect on profile assessment was reduced at 0.2/100 VAS, probably due to restricted facial view, which confounded attractiveness assessments (Liu et al., 2024). This highlights the important of assessing treatment effects on different facial views, and not only in profile aspects, since people present themselves from various viewing angles during daily interactions (Gkantidis et al., 2013; Zouloumi et al., 2019; Psomiadis et al., 2025). Therefore, we believe that the simultaneous frontal and profile assessments and the associated findings are more clinically relevant and should be primarily considered during treatment planning and decision-making.

Overall, the different rater groups assessed similarly the patients’ pre-treatment facial attractiveness, as was the case for treatment effects on facial appearance (Psomiadis et al., 2023, 2025). This enhances the generalizability of the findings in terms of treatment benefits related to facial appearance during human interactions. Regarding facial attractiveness scores, there were only few small differences towards a more positive assessment by the patients’ group as compared to specialists’ groups, which were not considered important. Other studies, not directly comparable to ours, showed contradictory findings in this matter (Ng et al., 2013; Gkantidis et al., 2013; Sari-Rieger & Rustemeyer, 2015; Reis et al., 2021).

Among the strengths of the present study is the use of validated questionnaires on the respective population (Tsiouli et al., 2017; Zouloumi et al., 2019), the exclusion of outliers from the sample in terms of facial morphology, the pre-treatment group similarity, the balanced demographic and morphological characteristics of the treatment groups, the diverse groups of raters, including laypeople, the slightly modified entire facial photos, the simultaneous presentation of pre- and post-treatment statuses in random order, and the use of printed questionnaires that were fulfilled at standardized conditions. Furthermore, the multivariate analysis models allowed for simultaneous assessment of several factors and their interactions adding validity to the outcomes and enhancing the study findings interpretation and generalizability.

A limitation of the study is that facial attractiveness, as well as treatment outcomes regarding facial appearance, were assessed statically and functional aspects, such as the smile, were not evaluated. Thus, a potential positive effect of orthodontic treatment alone in dental and smile aesthetics (Coppola et al., 2023; Farshidnia et al., 2023) was not captured. Therefore, the social benefits from orthodontic treatment alone might have been underestimated here. Moreover, the study included only white individuals. The findings may be modified in individuals with different skin color, as well as in individuals with more extreme facial morphology. The aforementioned factors need to be assessed in future research.

Conclusions

This study highlights the critical role of initial facial attractiveness in shaping perceived treatment outcomes for patients with convex facial profiles and increased overjet. Patients treated exclusively with orthodontics were rated as more attractive at baseline compared to those undergoing combined orthodontic and orthognathic surgery. However, after adjusting for initial attractiveness, the surgical group showed significantly greater perceived improvements in facial and profile appearance, particularly among patients with lower initial attractiveness.

Minimal differences among rater groups confirmed the consistency of attractiveness assessments. The inverse association between pre-treatment attractiveness and perceived improvement suggests that less attractive individuals experience greater benefits. Combined orthodontic/orthognathic treatment led to substantial positive changes, while exclusively orthodontic treatment showed minimal impact.

Clinicians should incorporate these findings into patient counseling and treatment planning, providing individualized information on expected outcomes based on initial facial attractiveness to support informed, evidence-based decisions.

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