This article discusses the use of simulated body fluid (SBF) to test the bioactivity of materials. While many researchers have accepted the idea that SBF can be used to assess bioactivity, the authors argue that there is insufficient scientific evidence to support this assumption. They also suggest that the current methods for testing bioactivity in SBF may not be reliable. The article traces the history of SBF, noting that it was first used in the 1980s to simulate in vivo conditions. Over the years, SBF has become a common tool for testing bioactivity, with many studies using it to evaluate the ability of materials to form apatite. However, the authors argue that this approach is not always accurate, as some materials that form apatite in SBF do not form a bond with bone in vivo. The article also discusses the theory of crystallization, which suggests that the formation of apatite in SBF is not necessarily indicative of bioactivity. It explains that the formation of apatite depends on factors such as the size and shape of the material, the local supersaturation of the solution, and the kinetics of the reaction. The authors also highlight the variability of SBF solutions and the need for standardized protocols. They argue that the current methods for preparing SBF are not always reproducible and may lead to inconsistent results. They suggest that a more controlled and standardized approach to preparing SBF is needed to ensure accurate results. The article concludes that while the use of SBF for testing bioactivity is a useful tool, it is not always reliable. The authors recommend that further research is needed to develop more accurate and reliable methods for testing bioactivity. They also suggest that the use of SBF should be used with caution, as it may lead to false positive or false negative results.This article discusses the use of simulated body fluid (SBF) to test the bioactivity of materials. While many researchers have accepted the idea that SBF can be used to assess bioactivity, the authors argue that there is insufficient scientific evidence to support this assumption. They also suggest that the current methods for testing bioactivity in SBF may not be reliable. The article traces the history of SBF, noting that it was first used in the 1980s to simulate in vivo conditions. Over the years, SBF has become a common tool for testing bioactivity, with many studies using it to evaluate the ability of materials to form apatite. However, the authors argue that this approach is not always accurate, as some materials that form apatite in SBF do not form a bond with bone in vivo. The article also discusses the theory of crystallization, which suggests that the formation of apatite in SBF is not necessarily indicative of bioactivity. It explains that the formation of apatite depends on factors such as the size and shape of the material, the local supersaturation of the solution, and the kinetics of the reaction. The authors also highlight the variability of SBF solutions and the need for standardized protocols. They argue that the current methods for preparing SBF are not always reproducible and may lead to inconsistent results. They suggest that a more controlled and standardized approach to preparing SBF is needed to ensure accurate results. The article concludes that while the use of SBF for testing bioactivity is a useful tool, it is not always reliable. The authors recommend that further research is needed to develop more accurate and reliable methods for testing bioactivity. They also suggest that the use of SBF should be used with caution, as it may lead to false positive or false negative results.