الفهرس 
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Abstract
The current study was carried out to evaluate molar intrusion using two different modalities.
This study was conducted on 14 subjects (5 males and 9 females), mean age 15.14±2.81 years who had anterior open bite .The subjects were allocated randomly in two equal groups:
group A (RMI) and group B (TADs).
For all subjects the following records were taken: Medical and dental history, clinical examination, intra-oral and extra-oral photographs, study models and radiographic examination.
CBCT were taken before and after the 4 months of the intervention and the measurements were done by using surgical planning software (Mimics). Before inserting the appliance, a trans-palatal arch as well as lingual arch were inserted in the patient’s mouth in group A (RMI) while a trans-palatal arch only arch were inserted in the patient’s mouth in group B(TADs).
In group A, RMI 800 gms of vertical force were applied. In group B, one micro-screw was placed bilaterally in the buccal sides (1.6 mm in width, 8 mm. in length). They were placed in the interseptal bone between maxillary second premolar and first molar in right and left sides, a force of 250 gms was calculated by the force gauge and attached to apply directly to the micro-screw by using close power chain attached to the upper first molar bands hock.
A periodic follow up each month was done to assess the progress of the case and to check the stability of the appliance. The results were focused on molar intrusion ,molar tipping ,molar rotation ,anterior open bite , ANB angle and mandibular rotation.
In the skeletal measurements, the mean values of SNA has no significant difference in both groups while the mean values of SNB and Mandibular rotation were increased significantly in both groups,but the mean values of ANB and were decreased significantly in both groups.
In the dental measurements, the mean values of the upper first molar has significant difference in both groups while the mean values of the upper first molar buccal tipping has significant difference in group RMI only ,but the mean values of the upper first molar rotation has significant difference in group TADs only.And mean values of the lower first molar intrusion in group RMI has the only significant difference in lower first molar measurements.
In linear measurements, the mean values of the anterior open bite decreased significantly in both groups.
Finally, the mean values of the molar tipping and rotation has the only significant difference between RMI and TADS groups in the upper first molars, while the molar intrusion has the only significant difference between RMI and TADS groups in the lower first molars.