الفهرس 
Introduction .Only 14 pages are availabe for public view
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Abstract
This prospective clinical trial was conducted to assess the correction of class II malocclusion in mandibular retrognathic patients using a new simple and digitally driven technique. Patients were treated using bite raisers beveled in specific directions combined with fixed orthodontic appliance.
Sixteen patients with overjet ranging from 4 mm to 10 mm and mandibular retrognathia were recruited for this study from the outpatient clinic of the Orthodontic Department, Faculty of Dentistry, Ain Shams University. An intraoral scan using 3 shape trios intraoral scanner with advanced bite was performed for each patient using the George guage bite fork. Bite raisers were designed on 3 shape appliance designer on the premolars, and bonded in the oral cavity via a transfer tray of Erkodur 0.6 mm sheet, after 3D printing of the casts with the designed raisers.
Treatment results were assessed using standardized digital lateral cephalometric radiographs. The records were acquired at T0 “before the start of treatment” and T1 “after Class II correction or 8 months of raiser bonding”. Lateral cephalometric radiographs were used to assess the soft tissue, skeletal and dental effects of treatment in both the sagittal and vertical dimensions.
The facial profile was significantly improved. A Statistically significant increase was found in the facial convexity angle and soft tissue facial angle. A statistically significant decrease was found in the upper lip to esthetic plane.
The skeletal sagittal results showed a statistically significant increase in the pogonion to nasion perpendicular linear measurement and maxillo-mandibular differential. Also, the wits appraisal showed a statistically significant decrease.
The overjet and overbite decreased significantly both statistically and clinically. The overbite reduction was probably due to upper and lower first molar extrusion. The labiolingual inclination of upper incisor was found to decrease significantly to be within normal range. The lower incisor was protruded keeping its normal labiolingual inclination. The lower first molar was mesialized significantly.
For the upper transfer trays, the root mean square was 0.7 with S.D. 0.29. For the lower transfer trays, the RMS was 0.57 with S.D. 0.26. This means that the total deviation between the designed upper and lower blocks and the bonded blocks showed no clinical significance. This means that the bite raisers could be accurately produced via this 3D printing technique.