Effect Of Different Techniques of CAD/CAM Designed Frameworks on The Supporting Structures of Kennedy Class I Cases

Abstract

This study was conducted to radiographically evaluate the effect of the different techniques of PEEK frameworks fabrication that were virtually designed using the CAD/CAM system on the supporting structures in mandibular Kennedy class I distal extension cases, by using long cone parallel technique. Fourteen patients with mandibular Kennedy class I and opposing short Kennedy class I were chosen from the outpatient clinic of the Prosthodontic Department Faculty of Dentistry, Ain Shams University. The last standing abutment for all patients was the second premolar. After receiving zirconia primary crowns that were digitally designed and milled, patients were randomly divided into two groups: Group I: Seven patients were rehabilitated with digitally designed telescopic RPDs, milled from BioHpp blank. Group II: Seven patients were rehabilitated with digitally designed telescopic RPDs, pressed from BioHpp granules. The telescopic partial denture framework was designed using the partial-cad module, which is an add-on module in the Exocad software, as follows: model was surveyed, and undercuts were determined. All unfavourable undercuts were blocked out by the software and a modified cast was created. Denture base meshwork was then outlined. Then the outline of the lingual plate major connector was drawn. External finish line between denture base meshwork and major connector was then drawn. For both groups, the final design was sent to the CAM software to be initially milled from castable polymethyl methacrylate resin, for intra-oral inspection.