الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The treatment of Class II malocclusions has always been a subject of great interest for orthodontists. The use of so-called “distalization” mechanics to correct Class II malocclusions is a common treatment modality. Many devices have been developed and used to distalize the maxillary molars and show positive clinical results. Some appliances need patient compliance but with time many studies try to shorten the treatment period and thus encourage patients to use the method of compliance efficiently to correct Class II malocclusion. With the introduction of skeletal anchorage the problem of loss of anterior anchorage with distalization was overcome.
In this study the MASBD was used for bilateral distalization of maxillary first molars and was tested for its effect on the rate of tooth movement during distalization.
Twenty patients with age ranging from 15 to 30 years were recruited from the out-patient clinic of the Orthodontic Department of the Faculty of Dentistry Ain-Shams University. All patients required maxillary molar distalization as part of their orthodontic treatment plan. Impression for appliance fabrication was done then mini-screw implants were inserted with appliance cementation.
The rate and type of maxillary first molar movement was assessed through the analysis of successive digital model scans taken every 4 weeks. The three-dimensional changes accompanying the maxillary first molar distalization were evaluated by analyzing pre-treatment and post-treatment-distalization CBCT and digital models revealing distal tipping of maxillary permanent canines and molars, statistically significant but clinically insignificant maxillary molar intrusion, no rotational movement were observed throughout the distalization period and reduction in the maxillary inter-molar width. The maxillary canines showed distal tipping tooth movement, palatal crown/labial root movement and significant extrusion was evident.
The mean distalization period was 6 months from the day of appliance cementation in the patients’ mouth and the beginning of class II elastics application with mean distalization amount 2.3 mm at the end of the distalization period, while the mean rate of tooth movement was 0.3 mm/month.