Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

Statement of the problem: Impression making is a critical clinical step to record accurately the three dimensional intraoral relationships among implants, teeth and adjacent structures. Inaccuracy during impression making inevitably leads to laboratory errors resulting in lack of precision and misfit of the final prostheses. Several clinical variables may affect the precision of impression particularly in the presence of multiple angulated implants. The aim of this study was to evaluate the effect of implant angulation tray type on dimensional accuracy of open tray implant impressions. A unilateral free end saddle dentate acrylic maxillary model resembling Kennedy class II starting from a missing canine was used in this study. Three models were duplicated from the acrylic model into epoxy resin master models. In model, three implants were inserted in the sites of missing canine, second premolar second molar. According to the direction of implant insertion, the master models were classified into three groups: Group 1: The three implants were inserted with 0{u00B0} angulation (straight, control group). Group 2: The three implants were inserted with 15{u00B0} angulation. Group 3: The three implants were inserted with 25{u00B0} angulation. For all groups, open tray impressions were taken. Impressions of each group were subdivided according to the tray type into two subgroups: Subgroup A: Open tray impressions using custom made trays. Subgroup B: Open tray impressions using ready made trays. All impressions were poured with type IV dental stone to obtain stone casts. Dimensional accuracy of the impressions was assessed using the travelling microscope

Issued also as CD