Performance of high-translucent zirconia CAD/CAM fixed dental prostheses using a digital workflow: A clinical study up to 6 years

BACKGROUND/PURPOSE: Zirconia has recently become a popular material for fixed restorations. The purpose of this study was to use a digital workflow to fabricate monolithic zirconia fixed dental prostheses (FDPs) and assess the connection between variable connector sizes compared to their clinical performance. MATERIALS AND METHODS: Clinicians evaluated monolithic zirconia FDPs in 58 patients. After definitive impressions were made, stone casts were obtained. The stone casts were scanned to a standard triangle language (STL) file. A digital wax up was fabricated, and corresponding provisional restorations were milled. Final FDPs were fabricated from a high-translucent zirconia material. During digital fabrication, the connector area of each FDP was recorded while meticulous attention was paid to ensure that the connector cross-sectional area was ≥9 mm(2) for the 3-unit restorations (pontic to retainer) and ≥12 mm(2) for the 4-unit restorations (pontic to pontic). Biological an technical outcomes of the FDPs were performed at 1 week, 6 months and then annually for 6 consecutive years. RESULTS: A total of 23 men and 35 women received a total of 63 full-contour zirconia FDPs in the posterior regions and were observed for a time period ranging between 50 and 70 months. No decementation occurred and no caries were detected during the observation period, however signs of gingivitis were detected in 4 patients. The dimension of the connector areas was 12 mm(2) in the two broken 4-unit FDPs. CONCLUSION: The results of this study suggest that the use of digital scanning and milling to fabricate monolithic zirconia FDPs of posterior regions may be an acceptable alternative restorative approach to traditional metal-ceramic restorations.