Evaluation of dental and skeletal effects of maxillary expansion in early mixed dentition using modified haas expander or ni-ti memory LEAF-expander

Aim: The aim of this study was to evaluate and compare the dentoalveolar and skeletal effects of maxillary expansion in early treatment between rapid maxillary expansion device Modified Haas and slow maxillary expansion device Ni-Ti Memory Leaf Expander- both anchored to deciduous teeth- and decide whether one is superior to other. Materials and method: A total of 38 patients who were treated between the years 2016-2020 in Orthodontics Department, Baskent University Faculty of Dentistry and met the inclusion criteria were included in the study. Their initial (T0) and post-expansion (T1) records after retention period were taken. Lateral and posteroanterior cephalograms and dental models were evaluated in the study. The patients were divided into two groups according to expansion screw of choice- Group 1 (modified Haas) or Group 2 (Niti Memory Leaf Expander). Group 1 consisted of 18 and group 2 consisted of 20 patients. The lateral and posteroanterior cephalograms were analised using Dolphin Imaging software. The dental models were scanned using 3Shape 3D Scanner and converted to digital stl models. The digital models were evaluated with Blender 2.90 Version Software. Student's test or Mann Whitney U tests were used to evaluate the statistical differences between groups. Results: There were no significant differences between the groups in terms demographic characteristics. Evaluation of lateral cephalometric films at T1 showed no statisticaly significant differences between the two groups in terms of results and the amount of the changes occurred after maxillary expansion (p>0,05). All posteroanterior film measurements- internasal and inter-jugular widths and distance between antegonial notches- were significantly higher for both groups at T1 and there were no significant differences between the groups in terms of the amount of increase (p>0,05). 3D model measurements showed significant changes at T1 for both groups for total surface area, anterior, middle and posterior surface area, molar tipping angle, upper and lower molar widths and arch perimeter. The amount of increase in anterior area and molar tipping angle was higher in Group 1 (p= 0.010 ve p=0.009). Conclusion: Both maxillary expansion devices produced similar successful results. Therefor we can conclude that the new Ni-Ti Leaf expander can be a safe and effective alternative in early treatment of maxillary deficiency with the advantage of eliminating patient and/or parent cooperation.