Evaluation Of Marginal Bone Height Changes And Biting Force In Screw Retained Implant Prostheses Using Reinforced Resin Vs Monolithic Zirconium

Inclusion Criteria: * Mandibular Class II, partially edentulous patients that enables measuring the marginal bone height changes and values of biting forces intra-orally. * Fully dentulous edentulous opposing Maxillary arch. * Patients with normal class I jaw relationship. * Patients that require fixed restorations for functional and esthetic reasons * Age range (30-60 years). * Cooperative patients those are willing to attend all follow-up periods. * Patients with healthy attached mucosa of appropriate thickness free from any inflammation. * Patients with healthy bone of appropriate thickness, width and height free from any inflammation. * Patients without any medical conditions that contraindicates implant placement. Exclusion Criteria: * Patients with Parkinson's disease * Patients with xerostomia. * Patients with a history of allergy to resins and/ or zirconia. * Patients with a medical systematic condition that contraindicate implant placement. * Patients smoking more than 10 cigarettes per day. * Patients with pathological changes of residual ridges as recurrent or persistent ulcers, osteomyelitis and infections. * Patients with large irregular bony exostosis. * Patients with medical or psychological conditions as physical disability or mental retardation that hinder cooperation in the follow up visits and answering the questionnaires.