Clear Orthodontic Expander Versus Hyrax

This will be a multicenter randomize clinical trial with two-arm parallel groups, and will be conducted at the Department of Orthodontics, College of Dentistry, University of Baghdad, as well as different specialized dental centers affiliated with the Iraqi Ministry of Health, and some private clinics. The sample size will be calculated based on previous studies with similar aim to measure the skeletal expansion. A minimum sample size of 17 patients was required, and in order to account for a 15% dropout, a total of 20 patients will be recruited for each group (new clear expander and hyrax expander). The amount of 2.5 mm or greater of maxillary sutural opening will be considered clinically effective. Two randomizations will be employed, one for the expander type and the other for the cleaning method of the new expander, a computer random generator will be used to develop a simple randomization with an equal allocation ratio (1:1) and without stratification. Data Collection and Measurements will be include, CBCT evaluation, Intraoral scan of the maxillary arch evaluation, overjet and overbite, CBCT-derived cephalometric images will be used to measure the maxillary mandibular plane angle, Microbial evaluation after using two different methods for cleaning the new clear expander and at the end of the treatment, the patient will be asked to fill out a questionnaire about the treatment, giving information about their experience and satisfaction during treatment. Data will be analyzed using the Statistical Package for Social Sciences for Windows, version 26.0, including Descriptive Statistics 9numbers, frequencies, percentages, mean, median, and standard deviations), Reliability Statistics (an intraclass correlation coefficient), and Inferential Statistics (Levene's test, Shapiro Wilk test, Paired samples t-test and Independent samples t-test).