Ethical Approval
This study received ethical approval from the Institutional Review Board of King Abdullah International Medical Research Center, Riyadh, and is reported according to the Strengthening the Reporting of observational Studies in Epidemiology (STROBE) guidelines for observational studies.[22] Written informed consents were obtained from those parents who agreed to participate in this study.
Study design and study subjects:
This cross-sectional study was conducted among 250 caregiver/child (11-14-year-olds) dyads seeking orthodontic consultation at the orthodontic center at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia. All children who are currently undergoing or had undergone orthodontic treatment in the past were excluded from the study.
Sample Size:
The mean CPQ11–14 score in the unexposed group (those without treatment needs, as defined by the DAI) was taken as 15.7 (standard deviation [SD] 16.7) and in the exposed group (those with treatment needs, as defined by the DAI) was taken as 25.5 (SD 16.5).[4] The ratio of exposed to unexposed was 1:1, and a correction factor of 2 (design effect) was applied to increase precision. The minimum sample size to satisfy the requirements was estimated to be 184 children. Taking into consideration possible nonresponse attrition, it was determined that 250 children would be required to obtain a power of 80% with a 95% confidence interval (95% CI).
Data collection methods, instruments used, measurements :
This cross-sectional study was conducted between September to December, 2017 at the dental center of King Abdulaziz Medical City (KAMC) Riyadh, Saudi Arabia. Convenient sampling technique was adopted to recruit the participants for this study. Data were collected using questionnaires and clinical examination. The questionnaire collected the background information of the parents and the CPQ11–14. CPQ11–14 consists of 16 closed-ended questions that are divided into 4 domains of 4 questions each: oral symptoms; functional limitations; emotional well-being and social well-being. Each questions was scores as: 0-never, 1-once\twice, 2-sometimes, 3-often and 4-every day\almost every day. Each domain was added separately to give a mean total CPQ11–14 score.The scores ranged from 0 to 64, with lower scores representing a better quality of life. In addition, global rating of oral health was assessed using two specific questions: 1) rate the quality of their oral health (scored as: 1-fair, 2-good, 3-very good, 4-excellent; and 2) the importance of good oral health for general well-being (scored as: 1-less important, 2-somewhat important, 3-important, 4-very important).
Malocclusion was assessed using Dental Aesthetic Index (DAI) (number of variables= 10).[23] The DAI measures 10 prominent traits of malocclusion, weighted on the basis of their relative importance, to produce a single score.[24] The 10 traits are: missing teeth, crowding, spacing, diastema, overjet, reverse overjet, and open bite and molar relationship. Each variable is given a certain score according to the criteria proposed by its author. The scores are further calculated according to a formula that will result in a final single score ranging from 0 to 36 or higher. DAI of 25 or below are considered normal; 26-30 are those with definite malocclusion and treatment is elective; 31-35 denote severe malocclusion with treatment considered as highly desirable; scores of 36 and higher represent very severe malocclusion with treatment indicated mandatory. Five final year dental students underwent training and calibration for recording DAI at the College of Dentistry, King Saud Bin Abdulaziz University for Health Science Studies, Riyadh. Kappa scores for inter- and intra-examiner reliability were 0.80 and 0.86 respectively.
Data Management and Analysis Plan:
Data were entered and cleaned using SPSS version 22 (Statistical Package for the Social Sciences for Windows; SPSS Inc., Chicago, IL, USA). Multivariate analysis of variance (MANOVA) was used to assess differences between domain and total CPQ11–14 scores with the co-variates (socio-demographic variables and DAI categories) . Post hoc comparisons between pairs of malocclusion groups were conducted using Bonferroni test. A p value of <0.05 was chosen as the cut off for statistical significance.