Thesis submitted to Faculty of Dentistry, Ain Shams University, for Partial Fulfillment of the Doctor Degree in Oral and Maxillofacial Prosthodontics

Abstract

Fourteen patients were selected with bilateral distal extension partially edentulous lower arches with the last standing tooth is the premolars from the outpatient clinic, Proshtodontic Department, Faculty of Dentistry, Ain shams University. Preliminary impressions were made for upper and lower arches to produce study casts. Study casts were mounted using provisional jaw relation record. Diagnostic and radiographic template was constructed on the lower cast. Root form conventional implants were inserted according to the manufacturer's instructions in the second molar area bilaterally. The ball and socket was used as posterior retainer. Preliminary surveying of the lower study cast was carried out to establish a suitable path of insertion and removal, determine and measure retentive undercut and to determine the needed mouth preparation. The partial denture was constructed and inserted in patient's mouth three months after implant placement. Patients had the same partial denture design except for the clasps placed on the abutments anterior to the edentulous area. Accordingly patients were randomly divided into two groups seven patients each. Group 1: Patients were received implant retained partial overdentures retained anteriorly by RPI clasps and posteriorly by ball and socket attachment. Group 2: Patients were received implant retained partial overdentures retained anteriorly by Aker clasps and posteriorly by ball and socket attachment. The following data were obtained at denture insertion, six and twelve months post insertion, Pocket depth of the abutment teeth was evaluated using graduated periodontal probe. Radiographic evaluation of changes in bone height of the abutments and implants was carried out using digital panorama. Follow up and data collections were performed at the time of partial overdentures delivery, six and twelve months after denture delivery. At the end of each follow up appointment the patients were motivated to keep proper oral and denture hygiene. The result of this study revealed that Partial overdentures with Aker clasp retainer shows more bone loss around the implants and the abutment teeth than that retained with RPI clasp although this different was statistically non significant while Partial overdentures with Aker clasp retainer shows more increased in pocket depth than that retained with RPI clasp and this different was statistically significant.