Clinical evaluation of retained preload and cement washout in screw- and cement-retained implant prosthesis

Purpose: The aim of this study was to evaluate the clinical performance of screw- and cement-retained implant prosthesis (SCP) design in terms of retained preload of abut- ment screws and cement washout. Materials and methods: Patients with the partial posterior edentulous areas comprised the study group. Implants were placed, and SCPs were delivered after 3 to 6 months healing. Follow-up examinations were performed. The implant survival rate and the prosthetic success rate were evaluated. The retained pre- load ratio of abutment screws and the prosthetic decementation ratio were measured. Results: Twenty one SCPs (forty three implants)in twenty patients were followed up to 64 months. All of the implants survived during the follow-up period (mean follow-up: 34 months). The prosthetic success rate was 100 % considering no abutment, screw, porce- lain or metal frame fractures, as well as no screw loosening. The retained preload ratio of SCPs at the end of follow-up period was 97.61% (±16.29) and the decementation ratio was 9.5 %. Conclusion: Within the limitations of this clinical study, SCP design showed favorable short-term clinical performances in respect of screw loosening and cement washout. (J Korean Acad Prosthodont 2015;53:301-9)