الفهرس 
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Abstract
SUMMARY
The current study involved two routes in vivo and in vitro investigations conducted on completely edentulous maxillary arch restored by acrylic complete denture and reinforced acrylic denture, then the retention and fracture resistance of the maxillary dentures will be evaluated.
Seven patients with completely edentulous maxilla will be selected from the outpatient clinic of prosthodontic department, faculty of dentistry, Ain shams university.
For each one of the patients three upper denture has been constructed.
1. Conventional heat cured acrylic denture base, (controlled group)
2. CAD/CAM Zirconia reinforced acrylic denture group (Z)
3. CAD/CAM BIOHPP reinforced acrylic denture group(B)
A primary impression was taken from patient presented to the removable prosthodontics department Ain Shams University using impression compound, to pour a stone model for maxillary and mandibular arche.
A special tray was constructed to have a secondary impression, using green stick for border molding and zinc oxide eugenol for the secondary impression. The secondary impression was poured into master cast. A silicone rubber mold was made for maxillary cast to be used for duplicating the model and to have three identical casts.
An occlusion block was made to record jaw relation. Check extension, retention and stability for the trial denture base and then vertical dimension determination the rest and occlusion. then using the face bow record to mount the maxillary cast on the semi adjustable articulator and using centric relation to mount the mandibular cast.
After mounting the casts three identical sheets of acrylic teeth were used for setting up of teeth, according to the anatomical and mechanical considerations (where incisal edges of anterior teeth and central fossa of posterior teeth were arranged on the crest of the ridge). The occlusal plane of the mandibular teeth was set from the tip of the canine to the level of the two third of the retromolar pad.
After try in checked the denture was processed as usual manner for the controlled group (without reinforcement) using heat cured acrylic resin following conventional long polymerization cycle, finished and polished in the usual manner. And for the reinforced dentures the frameworks designed first.
After that Using extra oral scanner to scan the maxillary cast (DS Mizar). And then it was uploaded to dental wings software, the framework was designed as the following it was extended 2 mm buccal, labial and palatal on the residual ridge and palatal extension framework extend from the molar area on the right side to the molar area in the left side. 1 mm tissue stops were made in the fitting surface of the framework and then the design added to the scanned model. Then it was converted to STL file for milling process.
The STL file was milled from BIOHPP blank using sizes (1,2,0.6 mm milling burs with the thickness of the blank was 16 mm. and the same process done for the zirconia blank, which is 22 mm in thickness followed by complete sintering in the furnace at 1,350°C to 1,500°C to achieve its final shape , using five-axis dental milling machine After milling the frameworks, it was seated on the cast to check its fit and accuracy before denture processing.
After processing the dentures was finished and polished and then retention was measured using digital force gauge. Chewing simulator was used to apply dynamic cyclic loading to each complete denture after initial retention was measured. Retention was measured after chewing simulator.
A universal testing machine was used to compare the fracture resistances of the complete dentures made with different reinforcing materials.
Data was collected, tabulated, and statistically analyzed.