Objectives: the aim of the study is to evaluate radiographically the crestal bone height change around all on four implant supported hybrid prosthesis Material & Methods: Fourteen patients were selected from Ain shams Outpatient. clinics having completetly edentulous maxilla opposed by full dentulous mandible and they were properly diagnosed for implant placement. Implant sites were planned virtually and a 3D printed surgical guide was made. The implant had been installed in proper position and angulations using the surgical guide. Patients were randomly divided into 2 groups, Group I; received a hybrid prosthesis on delayed loaded four implants, Group II; received a hybrid prosthesis on immediately loaded four implants. Postoperative CBCT was performed at time of pickup (base line), 6 and 12 months Results: Although the data obtained revealed that group I showed lower level of crestal bone height change compared to group II, statistical analysis of the data revealed insignificant difference during the one year follow up period. Conclusion: in all on four implants delayed loading hybrid prosthesis shows no significant difference regarding bone resorption around implants than in all on four implants immediately loaded hybrid prosthesis

The Purpose of this study is to is to compare the effect of occlusal adjustment using T scan III and articulating paper on the vertical bone height changes around dental implants supporting lower single fixed detachable hybrid prosthesis Material and method: Fourteen male patients having completely edentulous mandibular arch and full dentate in the maxillary arch were selected from the outpatient clinic prosthodontics department faculty of dentistry Ain Shams University to participate in this study . All Patients were rehabilitated with six implants retaining mandibular fixed detachable prosthesis designed by CAD/ CAM. According to the method of detection of occlusal errors and adjustment the patients were divided into two groups, Group I in which T scan III device was used to detect occlusal errors and group II where articulating paper was used in the patient mouth and occlusal adjustment were made according to the tool used. Radiographic evaluation using CBCT was done to evaluate the amount of vertical bone loss around the supporting implant throughout the follow -up period.Results : There was increase in vertical bone loss in group I and II through-out the follow up period and on comparing the two groups there was a significant difference in the vertical bone height changes around the supporting implants after one year from the follow up period where group II showed more vertical bone loss. Conclusion :Within the limitation of this study, it could be concluded that the use of t scan III device allow for better occlusal adjustment in case of implant supported lower single denture than articulating paper and resulting in less vertical bone loss around the supporting dental implants.

Purpose: The aim of this study was to evaluate the effect of using different locator attachments with a different retention value and ball and socket attachment on the bone height changes in Implant Supported class I removable Mandibular partial Overdenture. Introduction: The use of osseointegrate dental implants is one of the most successful treatment options to solve the problem of distal extension cases. A critical factor affecting the success of an implant is the manner in which mechanical stresses are transferred from the implant to the bone. One of the factors which affect the amount of force transmitted to the implant is the choice of the attachment. The Locator attachment system is a self-aligning and has dual retention, supplied in different colors; with a different retention value (white, orange and blue). The white housing has light retention, the orange housing has standard retention, and the blue has high retention while the ball and socket attachments consist of a titanium male unit and an easily replaceable rubber ring female unit that is retained in a metal retainer ring. The question is which of the various Locator attachment system used to retain mandibular partial overdenture affect the magnitude of stresses transmitted to the implants thus affecting the bone height changes around the implants. Material and methods: Twelve class I mandibular partially edentulous patients with opposing full dentate maxillary arch were selected from the from the Outpatient clinic, Prosthodontic Department, Faculty of Dentistry, Ain shams University. For all the patients extra and intraoral examinations were done associated with the proper laboratory investigations. Acrylic temporary partial denture was made for all the patients, the partial denture was duplicated into clear acrylic resin model then the model was scanned using CBCT machine and the DICOM data was processed to obtain STL file for the model. The digital image was performed and the virtual implant was placed in the most optimal position at the first molar area according to the surgical and prosthetic design.