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FULL-MOUTH ZIRCONIA-BASED IMPLANT-SUPPORTED FIXED DENTAL PROSTHESES. FIVE YEAR - RESULTS OF A CLINICAL PILOT STUDY. Figure 1. Patient M.A. (female, 68 y). Intraoral photograph before surgery, frontal view a Figure 2. Patient M.A. Immediately post-surgery X-ray b Figure 3 a, b. Patient M.A. Frontal and lateral smile with the final prostheses the CAD-CAM manufacturing dental technique. Nonetheless, some problems are still unsolved. In particular, technical complications like framework fracture and veneering porcelain chipping (3,4) also in case of implant-supported zirconia-based fixed dental restorations (5,6). Different methods have been suggested to solve the problem of chipping veneering porcelain. In brief they could be summarized as follows: - use of anatomically contoured framework design with respect to the veneering ceramic thickness necessity (between 1.5 to 2 mm) (7); - slow heating and cooling regimes when porcelain is fired on zirconia (8); - the press-over veneering material technique (9); - the sintering technique where CAD-CAM lithium disilicate veneer is linked to a zirconia framework (10). The clinical necessity to collect data in order to understand, control and avoid the high percentage of chipping (40%) that occur in full-mouth implantsupported zirconia-based fixed dental prostheses (FMIZBRs) (11) is the objective of this clinical trial. In this paper we provide the 5-year results of a pilot study on FMIZBRs. STOMA.EDUJ (2014) 1 (2) Figure 4. Patient M.A. Chipping complication at the two-years recall visit. The chipped surface was polished with patient’s satisfaction MATERIALS AND METHODS Patient selection Between March and July 2014 five women aged 55-75 years were selected from dental hygiene clinical recall appointments in a private Milan dental clinic. They all had received FMIZBRs from the same private practice between January 2008 and January 2009. Inclusion criteria were good general health without severe general and local medical or psychological conditions (as reported by the patients), and edentulous maxillary and mandibular dental arches for at least three months (Fig. 1). All subjects provided informed consent for the clinical procedures, in accordance with the Helsinki declaration and the Italian law. Five years extended warranty for the restorations was offered in case of failure. All subjects had confirmed their informed consent already provided to the clinical procedures in conformity with current guidelines for good clinical practice (12). An independent operator, who did not participate in the original prosthetic procedures, performed all evaluations. The survival rate was defined as surviving fixed dental prostheses minus altered fixed dental 139