58 Dental Press Implantol. 2015 Jan-Mar;9(1):58-65 ©2015 Dental Press Implantology original article Abstract / Introduction: several types of synthetic material have been used to correct bone defects, among which is calcium sulfate. Objective: the present in vitro study aimed at assessing the bioactivity of calcium sulfate in simulated body fluid (SBF). Methods: four specimens were prepared in polyvinyl chloride (PVC) circle matrices by mixing calcium sulfate with distilled water, as recommended by the manufacturer. Samples were immersed in 50 ml of SBF, at 36.5 ºC, for no longer than 21 days. The so- lution was renewed every three days. Bioactivity was assessed by means of Fourier transform infrared spectroscopy (FTIR). Results: The in vitro bioactivity test, carried out by means of FTIR analysis, revealed the presence of apatite formation over calcium sulfate substrate, thereby proving it to be a bioactive material. In addition, there was significant reduction in the size of the sample, which was associated with the process of resorption. Conclusion: within the limitations of the present study, it is reasonable to conclude that calcium sulfate is a bioactive material which is quickly absorbed. Keywords: Calcium sulfate. Biocompatible material. Fourier transform infrared spectroscopy. Studying the behavior of calcium sulfate: bioactivity and solubility in simulated body fluid How to cite this article: Martins TMA, Pavan AJ, Gavazzoni A, Bergamo ETP, Bonadio TGM, Weinand WR. Studying the behavior of calcium sulfate: bioactivity and solubility in simulated body fluid. Dental Press Implantol. 2015 Jan- Mar;9(1):58-65. doi: http://dx.doi.org/10.14436/2237-650X.9.1.058-065.oar Submitted: 28/06/2014 - Revised and accepted: 26/02/2015 Contact address: Thiago Modolo Azevedo Martins. Rua das Azaléias, 456 – casa 2503 – Conjunto Habitacional Inocêncio Vilanova Júnior – Maringá/PR - Brazil - CEP: 87.060-040 – E-mail: thiago_marts@yahoo.com Thiago Modolo Azevedo MARTINS 1 , Ângelo José PAVAN 2 , Alessandro GAVAZZONI 3 , Edmara Tatiely Pedroso BERGAMO 4 , Taiana Gabriela Moretti BONADIO 5 , Wilson Ricardo WEINAND 6 1 MSc in Integrated Clinic, Universidade Estadual de Maringá (UEM), Maringá, Paraná, Brazil. 2 Associate professor, Universidade Estadual de Maringá (UEM), Maringá, Paraná, Brazil. 3 PhD resident in Integrated Clinic, Universidade Estadual de Maringá (UEM), Maringá, Paraná, Brazil. 4 Master’s student in Dental prosthesis, Universidade Estadual de Campinas, (UNICAMP), Campinas, São Paulo, Brazil. 5 PhD resident in Physics, Universidade Estadual de Maringá (UEM), Maringá, Paraná, Brazil. 6 PhD in Physics, Universidade Estadual de Maringá (UEM), Maringá, Paraná, Brazil. » The authors report no commercial, proprietary or financial interest in the products or companies de- scribed in this article.