使用植入物及其各自的上结构来替换缺失的牙齿已成为牙科中的常见治疗选择。在临床应用之前，所有植入物组件必须在实验室研究中证明合适的耐久性。利用循环负荷的疲劳测试通常在体外模拟咀嚼功能。本系统综述的目的是评估用于种植体基台疲劳测试的加载条件，并比较循环加载后不同类型的种植体基台和基台连接类型的断裂强度。
本系统综述包括1970年1月1日至2014年12月31日期间在MEDLINE（PubMed）和Embase数据库中以英文发表的关于种植体基台循环载荷的原始科学论文。以下MeSH术语，使用搜索词及其组合：“体外”或“离体”或实验或实验室，“牙科植入物”，“植入物，实验性\“，”“假牙，植入物支持\“，“疲劳”，“牙科基台”，\"循环加载\",“循环疲劳”，“机械疲劳”，“耐疲劳性”，\"弯矩\",和“骨折”。两名审阅者进行了筛选和数据抽象。只有报告的研究，植入基台疲劳循环前后的静态断裂值，包括允许通过循环加载比较老化效果。使用加权线性回归分析(α=0.05)分析数据(N)。
选择过程产生了7项研究的最终样本。总的来说,疲劳试验的加载条件揭示了样品中的异质性，但可以对以下参数进行荟萃分析：a）基台材料，b)种植体-基台连接,和(c)疲劳循环次数。循环加载后，钛的平均断裂强度（508.9±334.6N）和氧化锆基台的平均断裂强度（698.6±452.6N）没有显着差异（p>0.05）。与外部连接（内部：774.0±582.3N；外部：481.2±137.5N；p=0.022）相比，循环载荷后的内部植入物-基台连接显示出明显更高的断裂强度。当加载周期数超过1,000,000个周期时，所有基台类型的平均断裂强度均显着降低（<1×10（-6）：1047.0±751.3N；>1×10（-6）：556.7±317.6N；p=0.032）。
这项荟萃分析的结果，有利于使用内部植入物-基牙连接与钛或氧化锆基牙材料相结合。循环次数对循环加载后的断裂强度有显著影响。
The use of implants and their respective suprastructures to replace missing teeth has become a common therapeutic option in dentistry. Prior to their clinical application, all implant components have to demonstrate suitable durability in laboratory studies. Fatigue tests utilising cyclic loading typically simulate masticatory function in vitro. The objectives of this systematic
review were to assess the loading conditions used for fatigue testing of implant abutments and to compare the fracture strength of different types of implant abutment and abutment-connection types after cyclic loading.
Original scientific papers published in MEDLINE (PubMed) and Embase database in English between 01/01/1970 and 12/31/2014 on cyclic loading on implant abutments were included in this systematic
review. The following MeSH terms, search terms and their combinations were used: \"in vitro\" or \"ex vivo\" or experimental or laboratory, \"dental implants\", \"implants, experimental\", \"dental prosthesis, implant-supported\", \"fatigue\", \"dental abutments\", \"cyclic loading\", \"cyclic fatigue\", \"mechanical fatigue\", \"fatigue resistance\", \"bending moments\", and \"fracture\". Two reviewers performed screening and data abstraction. Only the studies that reported, static fracture values before and after fatigue cycling of implant abutments, were included that allowed comparison of aging effect through cyclic loading. Data (N) were analyzed using a weighted linear regression analysis (α=0.05).
The selection process resulted in the final sample of 7 studies. In general, loading conditions of the fatigue tests revealed heterogeneity in the sample but a meta-analysis could be performed for the following parameters: a) abutment material, b) implant-abutment connection, and (c) number of fatigue cycles. Mean fracture strength of titanium (508.9±334.6N) and for zirconia abutments (698.6±452.6N) did not show significant difference after cyclic loading (p>0.05). Internal implant-abutment connections demonstrated significantly higher fracture strength after cyclic loading compared to external ones (internal: 774.0±582.3N; external: 481.2±137.5N; p=0.022). The mean fracture strength of all abutment types decreased significantly when number of loading cycles exceeded 1,000,000 cycles (<1×10(-6): 1047.0±751.3N; >1×10(-6): 556.7±317.6N; p=0.032).
The results of this meta-analysis, favour the use of internal implant-abutment connections in combination with either titanium or zirconia abutment materials. Number of cycles had a significant impact on the fracture strength after cyclic loading.
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