الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This study was performed to evaluate the radiographicaly the effect of implant number retaining fixed detachable lower single denture designed by CAD/CAM.
Fourteen completely edentulous male patients were selected from the out-patient clinic of Removable Prosthodontics Department, Faculty of Dentistry-Ain Shams University to participate in the study.
Patients were precisely selected and thoroughly examined in an attempt to reduce human variables and eliminate any factor that might adversely affect the results of this study.
All Patients were rehabilitated with fixed detachable lower dentures using Computer-aided design/ computer-aided manufacturing (CAD/CAM) technology. According to the number of implants used to support the dentures, patients were randomly divided into two equal groups
• group I: Patients in this group were rehabilitated by fixed detachable lower single denture retained by six dental implants (4.2 mm in diameter and 13mm in length).
• group II: Patients in this group were rehabilitated by fixed detachable lower single denture retained by four dental implants (4.2 mm in diameter and 13mm in length).
Standard clinical and laboratory techniques were followed for complete denture construction for all patients. The applications of 3-dimensional (3-D) imaging (computerized tomography scan), 3-D software for treatment planning, and fabrication of computer- generated surgical guides using additive prototyping were followed for all patients. Surgical installation of the implants was performed under strict aseptic conditions and the initial implants stability was measured using Osstell to ensure immediate loading was possible. Provisional hybrid PMMA prosthesis was delivered to the patient for immediate use throughout the 3 months healing within 3 days of implant installation. After healing, the adjusted PMMA was scanned for Monolithic Zirconium milling and subsequent veneering.
All patients were scheduled for follow up visits to evaluate marginal bone height changes each implant using linear measurement system supplied by cone beam computed tomography. CBCT records were obtained upon implant loading (Baseline), six Months, twelve Months and eighteen Months of follow-up period. The marginal bone loss at different intervals was obtained by calculating the difference in bone height at that interval from the base line measurements.