Comparison of Maxillary Dental Expansion Using Smartee Clear Aligner With and Without S11 Expander: A Randomized Clinical Trial

Inclusion Criteria: * 1- healthy cooperative female and male patients who will undergo maxillary expansion with Smartee aligners, A young adult/adult patients starting from age of 18 up to 35 years old. 2- patients with maxillary compression of non-skeletal origin, moderate dental crowding in the upper arch (4-8mm). 3- patients with unilateral or bilateral crossbite, patients will be treated with intermaxillary elastics without distalization or mesialization of the dental arches. 4- patients with sufficient clinical crown height (greater than 4 mm), no mesial rotation of the upper first molar. 5- there is good compliance during the treatment (wearing aligners for 20 hours per day). 6- good quality x-rays with appropriate visualization of landmarks and control of head rotation. 7- absence of periodontal disease, and absence of previous prosthodontic treatments of the upper molars. Exclusion Criteria: * 1- signs and/or symptoms of temporomandibular abnormalities (TMDs). 2- active periodontal disease. 3- prosthodontic rehabilitations of the maxillary molar or ankylosed teeth, and endodontic treatments of the maxillary molars. 4- patients requiring orthognathic surgery