Clinical Evaluation of Lithium Disilicate Pressed Zirconia and Monolithic Zirconia in Posterior Implant-Supported Prostheses

Purpose: The purpose of this study was to compare the clinical outcomes of lithium disilicate pressed zirconia prostheses and monolithic zirconia prostheses, which are widely used as posterior implant restorations, after 12 months of follow-up. Material and Methods: A total of 17 patients were treated with 60 implant-supported prostheses. After examination of implant survival rate, marginal bone loss, probing depth, plaque index, bleeding index, calculus index, and complications, independent T-test and chi-square test were performed to compare each group (Lithium disilicate pressed zirconia prostheses: n=30, Monolithic zirconia prostheses: n=30). Results: The implant survival rate was 100%. Marginal bone resorption was higher in the monolithic zirconia prostheses group (p<0.05). Probing depth, plaque index, calculus index, and bleeding index were higher in the lithium disilicate pressed zirconia prostheses group (p<0.05). Complications occurred in the monolithic zirconia prostheses group as connector fracture, and in the lithium disilicate pressed zirconia prostheses group as chipping. Conclusion: The periodontal index of lithium disilicate pressed zirconia was slightly worse, but the bone resorption was lower and only one chipping occurred on veneered layer. Therefore, lithium disilicate pressed zirconia is considered as a promising treatment option as much as monolithic zirconia in posterior implant-supported prostheses. However, long-term clinical studies are needed for reliable results (IRB No. PNUDH- 2014-001-MD).