## 3 Results
### Studies Included
[PERSON] [55] conducted a study with 230 adolescents to examine the influence of personality traits on the relationship between orthodontic treatment need and OHRQoL. While the treatment need did not differ by gender, girls reported significantly poorer emotional well-being. Regarding personality, girls were more agreeable, whereas boys scored higher in openness to experience and negative valence. Correlation analyses revealed weak associations between treatment need and overall OHRQoL, as well as with its emotional and social well-being subscales. Notably, extraversion, openness, and dispositional optimism were negatively correlated with many quality-of-life scores, while neuroticism was positively correlated with most OHRQoL dimensions. Through regression analyses incorporating ICON scores, extraversion significantly moderates the relationship between malocclusion severity and overall OHRQoL and emotional and social well-being. Similarly, openness to experience moderates the effect of malocclusion severity on the emotional well-being domain, indicating that higher levels of these traits may buffer the negative impact of malocclusion on quality of life. [PERSON] et al. [62] examined the relationship between personality traits and OHRQoL before and after Invaslign treatment in 50 patients. Results indicated that females experienced fewer negative oral health impacts after treatment than at baseline. Furthermore, regression analyses conducted separately by gender indicated that openness, extraversion, and conscientiousness significantly predicted post-treatment OHIP scores among males. In contrast, neither personality traits nor demographic variables significantly predicted treatment outcomes in the female group. [PERSON] et al. [64] explored how personality traits influence the aesthetic perception of different orthodontic appliances. Using an online questionnaire with 461 participants, the researchers examined the role of personality traits in evaluating orthodontic treatment options. Among laypeople, those who considered the smile \"very beautiful\" had significantly higher scores in extraversion, openness, and agreeableness than participants with less favorable evaluations. In addition, significant differences in personality traits were found based on the preferred type of treatment. Participants favoring aligners showed higher openness and agreeableness, while those preferring brackets had significantly higher neuroticism scores. The study of [PERSON] and [PERSON] [58] involved 67 patients aged 12-60 undergoing clear aligner treatment. Participants completed an online questionnaire assessing compliance and personality traits. The study found that 50.75% of patients demonstrated high adherence to aligner wear time and follow-up visits. Notably, younger participants (ages 12-34) and those in treatment for one year or less showed higher compliance. Males were significantly more compliant compared to females. No statistically significant correlations were found between personality traits and compliance behavior, suggesting that other factors, such as age, gender, and treatment duration, may substantially impact patient cooperation. [PERSON] and [PERSON] [65] investigated the relationship between personality traits (via the NEO-FFI) and compliance with Invaslign treatment among 22 adult patients. Of these, 55% were classified as cooperative, whereas 45% were noncompliant. The IOTN indices were similar between compliant and noncompliant groups. The findings showed that noncompliant patients had significantly higher neuroticism scores. Elevated neuroticism was further associated with an increased number of missed appointments, a discrepancy between the planned and actual number of aligners used at 6 months, reduced ability to control financial aspects related to treatment, and a negative correlation with the achieved movement of the upper premolars. Conversely, higher extraversion scores were linked with more frequent complaints about the treatment process and poorer oral hygiene outcomes at the 12-month assessment.