Long-term survival and success of zirconia screw-retained implant-supported prostheses for up to 12 years: A retrospective multicenter study.

STATEMENT OF PROBLEM: Despite the broad clinical application of zirconia for fixed implant-supported prostheses, evidence of long-term performance is sparse. PURPOSE: The purpose of this retrospective study was to evaluate the long-term clinical and radiographic outcomes of zirconia-based partial and complete screw-retained implant-supported zirconia fixed dental prostheses (ISZFDPs). MATERIAL AND METHODS: Records of patients treated with dental implants and ISZFDPs between December 2004 and June 2017 were screened. Eligible study participants, according to inclusion criteria, were contacted and invited to undergo clinical and radiographic examinations. Outcomes were evaluated as implant and prosthetic survival rates, prosthetic success rate, complications, marginal bone level (MBL) change, and soft tissue condition. Along with the effects of zirconia prosthesis type and level, the effects of implant type and connection, type of loading, and follow-up on MBL were tested with a generalized linear effects model (GLEM) (α=.05). RESULTS: A total of 118 patients were identified, of whom 20 (16.9%) were not available for clinical examination for various reasons. Ninety-eight participants (mean age 60.7 ±11.7 years) with 337 implants were included, of which 176 (52.2%) had been immediately loaded. A total of 111 ISZFDPs (96 zirconia connection and 15 titanium base) were investigated: 24 complete ISZFDPs with a zirconia connection (12.9 ±0.97 dental units, minimum 12, maximum 14), 72 partial with a zirconia connection (3.11 ±1.12, minimum 2, maximum 7), 15 partial with a titanium base (3.62 ±1.02, minimum 2, maximum 5). Forty ISZFDPs had been in function for ≥10 years (36%), 38 for 5 to 9 years (34.2%), and 33 for 2 to 4 years (22.8%). The mean follow-up time was 7.2 ±3.4 years. No zirconia fractures were identified. Two implants and 2 ISZFDPs failed, with chipping being the most common complication (13.5%). The implant survival rate was 99.4%, and the prosthetic survival rate was 98.2%. The cumulative prosthetic success rate was 91.9%. MBL change was -0.18 ±0.59 mm. Thirteen implants were treated for peri-implantitis (3.8%), and 9 for mucositis (2.7%), but presented healthy peri-implant soft tissues at the follow-up examination. A significant difference was found between the implant-level and abutment-level prostheses (P=.013), with less marginal bone loss observed in ISZFDPs delivered at the implant level. CONCLUSIONS: Zirconia-based screw-retained implant-supported prosthesis can be considered a reliable long-term treatment option for partial and complete edentulism. No zirconia fractures were experienced. Stable bone levels and low peri-implantitis rates were reported regardless of the ISZFDP type and level, implant type and connection, and type of loading.

Clinical reliability of CAD/CAM cross-arch zirconia bridges on immediately loaded implants placed with computer-assisted/template-guided surgery: a retrospective study with a follow-up between 3 and 5 years.

PURPOSE: The purpose of this study is to retrospectively evaluate the implant and prosthetic survival and success rates of zirconia-based, implant-supported, screw-retained, cross-arch restorations up to 5 years after placement. MATERIALS AND METHODS: Twenty-two consecutive edentulous patients (11 males and females, each; mean age 68.3 years) received 26 CAD/CAM cross-arch zirconia implant bridges (NobelProcera™ Implant Bridge Zirconia; Nobel Biocare AG, Zurich, Switzerland) supported by 4 to 10 implants each. All patients were followed for at least 3 years (range 36-60 months, mean 42.3 months). Clinical assessments were scheduled every 4 months during hygiene maintenance. Outcomes were implant and prosthetic survival rates, prosthetic success rate, any observed clinical complications, patient satisfaction, and soft tissue parameters. Fisher's exact test was used to assess associations between categorical variables. RESULTS: No dropouts occurred. The overall implant and prostheses survival rate up to 5 years was 100%. Three out of 26 restorations (five out of three hundred forty eight dental units) showed an adhesive chip-off fracture of the veneering ceramic, scoring a cumulative prosthetic success rate of 88.5% at the prosthetic level and 98.6% at the unit level. All 22 patients were functionally and aesthetically highly satisfied with their restorations. Successful soft tissue parameters were found around all implants. CONCLUSIONS: Industrially manufactured, zirconia-based, implant-supported, screw-retained, cross-arch restorations are a viable alternative to conventionally manufactured porcelain-fused-to-metal restorations for rehabilitating the edentulous patient.