Abstract
Objective: To investigate the influence of the combination of patient-specific abutments and titanium adhesive bases on the long-term in vitro performance of anterior crowns. Methods: Ten systems of screw-retained implant and adhesive base combinations (n = 8/group) were restored with zirconia or polyetherketone (PEEK) abutments and identical full-anatomical zirconia crowns. For simulating ...
Abstract
Objective: To investigate the influence of the combination of patient-specific abutments and titanium adhesive bases on the long-term in vitro performance of anterior crowns. Methods: Ten systems of screw-retained implant and adhesive base combinations (n = 8/group) were restored with zirconia or polyetherketone (PEEK) abutments and identical full-anatomical zirconia crowns. For simulating clinical anterior loading, implants were fixed at an angle of 1358 and submitted to prolonged thermal cycling and mechanical loading (TC: 6 x 3000 cycles, 5 degrees C/55 degrees C; ML: 100 N, 3.6 x 10(6) cycles) to cause and register fatigue failure. Failed restorations were examined by means of scanning electron microscopy. Surviving restorations were loaded to fracture. Data (mean +/- standard deviation) were statistically analyzed (ANOVA; Bonferroni; Kaplan-Meier-Log-Rank; alpha = 0.05). Results: Seven systems survived TCML without any failure. The other three systems showed loosening and fracturing of the screw (0.4-1.6 x 10(6) loadings) or debonding between base and abutment (0.002-3.4 x 10(6) loadings). None of the systems showed any fracture of the crown or failed bonding between abutment and crown. The Log-Rank test showed significant (p = 0.000) differences. Fracture data significantly varied (ANOVA p = 0.000) between the individual systems (minimum: 371 N; maximum: 763 N). Failures were mostly caused by bending or fracturing of the screw and in three cases by fracture of the abutment. Conclusions: Anterior implant-supported zirconia crowns on titanium adhesive bases and bonded patient-specific zirconia abutments provided good in vitro performance and high fracture resistance. Sufficient high torque moments and early re-screwing may be advised. Clinical relevance: Most adhesive base and abutment combinations may be appropriate for anterior application. Individual improvements may contribute to enduring success. (C) 2015 Elsevier Ltd. All rights reserved.
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