The Clinical Study Of Distalization Of Maxillary Molars By Clearaligner And Pendulum Appliance

Objective (s): To compare the treatment outcome of distalization of maxillary molars using Clearaligner and pendulum appliance in Angle's ?1 patients.Methods: Randomly select 40 patients with Angle's ?1 malocclusion who were treated in the Department of Orthodontics, the Attached Stomatology Hospital of KMMC during 2014.09-2016.12, with 20 patients treated with Clearaligner (group A)and another 20 patients with pendulum appliance (group B) for distalization of maxillary molars. Collect patients CBCT result before and after treatment, use NNT Viewer to measure the Three-dimensional change in distance and angle of molars to the front teeth after distalization. Data were processed by SPSS20.0 software.Results: 1 .Three-dimensional change of maxillary first molar after distalizaion.(1)change in mesio-distal direction: group A with 2.04±0.68mm of distal movement and 1.58±0.59°distal inclination; group B with 3.29±0.95mm distal movement and 10.27±1.32°distal inclination. The differences before and after treatment, and inter-group compare, has statistical significance ( P < 0.05 ) . (2) Change in buccal-palatal direction: group A with 0.78±0.34mm buccal movement and 0.40±0.04°buccal inclination; group B with -0.32±0.07mm buccal movement and 0.45±0.05°buccal inclination. The differences before and after treatment, and inter-group compare, has no statistical significance (P>0.05) .(3)Vertical change:group A with -0.49±0.08mm movement; group B with -0.79±0.05mm movement,suggesting intrusion. The differences before and after treatment, and inter-group compare, has statistical significance (P<0.05) . 2. Three-dimensional change of maxillary second premolar after distalizaion.(1)change in mesio-distal direction:group A with 0.50±0.19mm of distal movement and 3.65±0.71°distal inclination;group B with -1.32±0.18mm distal movement and -3.30±0.81°distal inclination. The differences before and after treatment, and inter-group compare, has statistical significance (P<0.05) . (2) Change in buccal-palatal direction: group A with 1.03±0.27mm buccal movement and 4.94±0.70°buccal inclination,differences before and after treatment has statistical significance (p < 0.05 ) . Group B with 0.23±0.12mm buccal movement and -0.38±0.08°buccal inclination,differences before and after treatment has no statistical significance (P>0.05) . The inter-group compare has statistical significance (p<0.05). (3)Vertical change: group A with -0.11±0.02mm movement, suggesting intrusion, differences before and after treatment has no statistical significance (P>0.05) ; group B with 0.83±0.23mm movement,suggesting extrusion,differences before and after treatment has statistical significance (P<0.05) .3. The angle change of maxillary central incisor before and after treatment.Group A with 1.05±0.35°labial inclination,group B with 7.26±0.80°labial inclination.The differences before and after treatment, and inter-group compare, has statistical significance (P<0.05), suggesting group B has greater labial inclination than group A.Conclusion(s): 1. Both Clearaligner and pendulum appliance are effective appliances for distalization of maxillary molars. 2. Clearaligner has better control in bodily distalization of molars. 3. Clearaligner causes less anterior teeth anchorage loss during distalization of molars.