This study was a cross-sectional survey that included male and female students aged 12–18 years. The researchers visited the schools for data collection which were randomly allocated by the Ministry of Education. School administrators were contacted to grant permission to conduct this study. The size of population (≈ 10,000), margin of error (5%), and anticipated proportion of population with the outcome (50%) were used to calculate the sample size (370), which was increased to 10% (N = 407). A convenient sample of 407 students was selected from 31 public male and female middle and high schools in Dammam, Al Khobar, and Dhahran, Eastern Province, Saudi Arabia. School children who provided written informed consent were eligible to participate in the study. Children with special care needs, debilitating medical conditions, or those without written informed consent were excluded from the study. Data collection began in April 2023 and was completed in June 2024. The school visits for data collection were scheduled according to the dates provided by the Ministry of Education.

The study included the distribution of self-administered questionnaires among school children. The questionnaire was divided into three sections. The first section included demographic data of participants, such as age, gender, class year, grade point average (GPA) in previous year, parental education level, and monthly family income. Two categories such as middle school and high school were used for class year question. The participants were asked to mention GPA as the percentage of overall scores earned in the last academic year. No education, school education, and college/university education categories were used for parental education. The economic status of participants was determined based on monthly family income, which had three categories such as low income (< 5,000 Saudi Riyal (SR)/month ), middle income (5,001–20,000 SR/month), and high income (˃20,000 SR/month) [20]. The second section contained an Arabic version of the Big Five Personality Inventory, and the last section included an Arabic version of the Child Oral Health Impact Profile-Short Form.

Literature shows several personality trait models, such as Big Five model (BFM), the HEXACO model, the Psychobiological model, and the Supernumerary Personality Traits, but BFM is the most dominant and most widely used in studies [5]. According to the BFM, conscientiousness is related to self-discipline, responsibility, and dependability; extraversion is characterized by talkativeness, sociability, and assertiveness; agreeableness is related to kindness, generosity, trust, and cooperativeness; neuroticism is characterized by emotional instability and experiencing negative emotions; and Openness is related to curiosity about the world and people, novelty, and trying new things [2, 21]. The Big Five Personality Inventory is a widely accepted scale for understanding personality traits, and has been extensively researched to predict behaviors, attitudes, and life outcomes. The study used the Arabic version of Big Five Personality Inventory, and it’s validity and reliability were assessed in a previous study conducted in Egypt [22]. The inventory consists of 25 statements with a 4-point Likert scale for each statement (No = 1, Some = 2, Much = 3, and Always = 4). Five items were related to the five traits of the BFM (openness, conscientiousness, extraversion, agreeableness, and neuroticism). The total score for each factor/trait ranges from 5 to 20, with higher scores indicating higher levels of personality traits [22]. In the present study, the values of Cronbach’s alpha were calculated and found to have acceptable to good internal reliability for extraversion (0.68), agreeableness (0.86), conscientiousness (0.81), neuroticism (0.82), and openness (0.79).

The study used a previously validated Arabic version of the Child Oral Health Impact Profile-Short Form (COHIP-SF19) was used to measure the OHRQoL of study participants [23]. The COHIP-SF19 questionnaire is comprised 19 items distributed over three conceptual subscales: oral health (5 items), functional well-being (4 items), and socio-emotional well-being (10 items). Responses were recorded as never = 0, almost never = 1, sometimes = 2, fairly often = 3, and almost all the time = 4. The scores on the negatively worded items were reversed. The total score on the COHIP-SF19 scale ranges from 0 to 76, with higher scores reflecting a more positive OHRQoL [24]. The present study showed that internal reliability of the COHIP-SF19 scale was very good (Cronbach’s alpha = 0.88).

Ethical approval (IRB 2023-02-019) for this study was obtained from the Institutional Review Board of the Deanship of Scientific Research, Imam Abdulrahman Bin Faisal University, Dammam. Approval was also obtained from public schools to collect data from the students. Hard copies of written informed consent forms were sent to the parents or legal guardians of school children a day before school visits. The children who returned consent forms were included in the study. The consent form included the purpose, objectives, and details of the study. Participants were assured of the privacy and confidentiality of their responses. The study adhered to the ethical guidelines of the Declaration of Helsinki.

The researchers visited the selected schools and provided hard copies of the questionnaires to 407 students in their classrooms. The participants were informed that there were no right or wrong answers, and they were asked to rate each statement in the questionnaire. They were allowed adequate time to respond to the questionnaire carefully and were provided with explanations if they were unable to understand certain questions or items to ensure that all questions were completely answered.

The collected data were entered into a Microsoft Excel spreadsheet and analyzed using the Statistical Package for Social Sciences (Version 22.0, SPSS Inc., Chicago, IL, USA). Cronbach’s alpha was calculated for the Big Five Personality Inventory and COHIP-SF19 questionnaire to evaluate the internal reliability of these instruments. Descriptive statistical analysis involved calculating the means, standard deviations, and frequencies of different variables, and displaying the results in tables and graphs. Shapiro-Wilk test was used to test the normal distribution of continuous data such as score of OHRQol and personality traits, and accordingly parametric tests were performed in the study. An independent samples T- test was used to compare the mean scores of personality traits between the male and female participants. The relationship between personality traits and OHRQoL was evaluated using the Pearson’s correlation test and multiple linear regression analysis. Statistical analysis was performed using a p-value < 0.05.