primary outcome:
Metal‐free materials for fixed prosthodontic restorations
Data for primary outcome failure could be calculated at 12 and 60 months intervals.At 12 months 194 participants were available for analysis. With regard to crown failure or crown complications there was insufficient evidence of a difference between either treatment approach (odds ratio (OR) 0.83 (95% confidence interval (CI) 0.05 to 13.44) and OR 4.31 (95% CI 0.49 to 37.57)) respectively (Analysis 1.1; Analysis 1.3).At 60 months 158 participants were available for analysis. A difference was shown in terms of crown failure (OR 17.52 (95% CI 5.07 to 60.54) (Analysis 1.2) in favour of conventional metal crowns. There was insufficient evidence of a difference when evaluating crown complications (OR 1.44 (95% CI 0.59 to 3.52) (Analysis 1.4).No data were presented with regard to aesthetics.Data for primary outcome failure could be calculated at 12 and 72 months intervals.At 12 months 37 participants were available for analysis. With regard to FDP failure there was insufficient evidence of a difference between either treatment approach (OR 9.00 (95% CI 0.96 to 84.50) (Analysis 2.1). Data for complications were not available at 12 months.At 72 months 22 participants were available for analysis. There was insufficient evidence of a difference in terms of FDP failure (OR 6.86 (95% CI 0.66 to 71.72)) (Analysis 2.2) while a difference for complications was found in favour of metal‐free FDPs (OR 0.07 (95% CI 0.01 to 0.75)) (Analysis 2.3).No data were presented with regard to aesthetics.Data for primary outcome failure could be calculated at 12 and 36 months intervals.At 12 months 34 participants were available for analysis. No FDP failure was reported in either treatment approach. Data for complications were not available at 12 months.At 36 months 34 participants were available for analysis. No FDP failure was reported in either treatment approach. There was insufficient evidence of a difference for complications (OR 1.94 (95% CI 0.38 to 9.88) (Analysis 2.6).At 36 months, an analysis of 34 participants showed insufficient evidence of a difference in patient aesthetic satisfaction changes (OR 15.40 (95% CI 0.78 to 304.61) (Analysis 2.7).At 12 months 19 participants were available for analysis. No failure and no complication were reported in either test and control group.At 24 months 19 participants were available. While no failure was reported there was insufficient evidence of a difference in terms of occurrence of complications (OR 5.59 (95% CI 0.23 to 133.61)) (Analysis 3.4).At 36 months 19 participants were still available. No failure was reported and there was insufficient evidence of a difference for complications (OR 2.00 (95% CI 0.15 to 26.73)) (Analysis 3.6).Patients' subjective ratings for aesthetic performance through visual analogue scale (VAS) was provided at the 24 months time interval. No statistically significant difference was shown (mean difference (MD) ‐0.34 (95% CI ‐0.85 to 0.17)) (Analysis 3.9).At 12 and 24 months 18 participants were available. No failure was reported for the test or control groups at either 12 or 24 months. At 24 months, there was insufficient evidence of a difference for complications (OR 6.33 (95% CI 0.26 to 152.86)) (Analysis 4.3).VAS for patient satisfaction (mm) was provided at one‐ and two‐year time intervals. There was insufficient evidence of any differences (VAS 1 year MD ‐4.65 (95% CI ‐18.75 to 9.45); VAS 2 years MD ‐0.03 (95% CI ‐7.65 to 7.59)) (Analysis 4.8; Analysis 4.9).Aesthetic evaluation through pink aesthetic score (PES) and white aesthetic score WES total was provided at two years with insufficient evidence of a difference (MD ‐0.77 (95% CI ‐3.00 to 1.46)) (Analysis 4.10).At 12 months 47 participants were available. With regard to abutment failure there was insufficient evidence of a difference between either treatment approach (OR 7.63 (95% CI 0.33 to 177.14) (Analysis 5.1), whilst no complications were reported.Primary outcome aesthetic evaluation data was reported as frequency of distribution of the Implant Crown Aesthetic Index (ICAI).At 12 months 18 participants were available. No FDPs failures were reported and with regard to complications there was a difference in favour of zirconia‐toughened alumina (OR 0.04 (95% CI 0.00 to 0.48)) (Analysis 6.2).At 36 months 18 participants were available. No FDPs failures were reported and with regard to complications there was a difference in favour of zirconia‐toughened alumina (OR 0.02 (95% CI 0.00 to 0.30)) (Analysis 6.4).At 60 months 18 participants were available. No FDPs failures were reported and with regard to complications there was a difference in favour of zirconia‐toughened alumina (OR 0.02 (95% CI 0.00 to 0.42)) (Analysis 6.6).At 120 months 17 participants were available. No FDPs failures were reported and with regard to complications there was a statistically significant difference in favour of zirconia‐toughened alumina (OR 0.02 (95% CI 0.00 to 0.48)) (Analysis 6.8).No data were presented with regard to aesthetics.At 12 months 40 participants were available. No FDPs failures were reported, no complications were reported.At 36 months 36 participants were available. No FDPs failures were reported and with regard to complications there was insufficient evidence of a difference (OR 2.80 (95% CI 0.66 to 11.92) (Analysis 7.3).No data were presented with regard to aesthetics.