Black-pigmented bacteria have close relationship with infected root canals, but there are some differences in detection rate. The purpose of this study is to analyze the main factors influencing the detection of these bacteria in infected root canals by comparing the results from a large number of domestic and foreign literatures, which include the sample size, the geographical difference, the sampling site, the clinical symptoms and the detection methods. We hope to find out the specific role of these bacteria in infected root canals by controlling the influential factors in the future.
