Evaluation of the Mechanical Reliability of Different Implant-Abutment Connections for Single Crowns According to the ISO 14801 Fatigue Test Protocol

Purpose: The aim of this in vitro study was to evaluate the mechanical behavior regarding dynamic fatigue of different implant-abutment connections and the unitary indication of abutments for all regions of the mouth. Materials and Methods: This experimental study developed according to international standards (ISO 14801:2007) was performed using five types of implants and abutments: G1-external hex smart implant and 17-degree universal abutment (EHS); G2-cortical external hex implant and 17-degree universal abutment (EHTi); G3-internal hex implant and 30-degree universal abutment (IH); G4-Morse taper implant (11.5 degrees) and 17-degree universal abutment (MT11.5); and G5-Morse taper implant (16 degrees) and 30-degree universal abutment (MT16). A 15-Hz cyclic loading was applied to the specimens with the maximum number of cycles set at 5 x 10(6). Success was defined when three samples supported 5 million cycles without failure. The maximum load supported from each group after dynamic loading was recorded. The Spearman correlation and the Lowess method were used to analyze the correlation between the number of cycles and the applied load, and the Kruskal-Wallis and Nemenyi tests were used for comparison between the abutments when reaching 5 million cycles. Results: There was a negative correlation (r < 0.00) and significant difference (P < .05) between the number of cycles and the load for each type of implant and abutment. The load values supported by each group after cyclic loading to achieve 5 million cycles were as follows: EHS, 225 N; EHTi, 215 N; IH, 220 N; MT11.5, 210 N; and MT16, 240 N. The MT16 implant-abutment assembly presented a significantly higher load (P = .024) than the MT11.5 implant-abutment assembly. Conclusion: All implant-abutment connections investigated in this study resisted average occlusal force values reported as acceptable in the literature and may be indicated for any region of the mouth.