Jenks, Daniel B.Ehrlich, YgalSpolnik, KennethGregory, Richard L.Yassen, Ghaeth H.2017-02-172017-02-172016-10Jenks, D. B., Ehrlich, Y., Spolnik, K., Gregory, R. L., & Yassen, G. H. (2016). Residual antibiofilm effects of various concentrations of double antibiotic paste used during regenerative endodontics after different application times. Archives of Oral Biology, 70, 88–93. https://doi.org/10.1016/j.archoralbio.2016.06.006https://hdl.handle.net/1805/11929Objective We investigated the residual antibiofilm effects of different concentrations of double antibiotic paste (DAP) applied on radicular dentin for 1 or 4 weeks. Design Dentin samples were prepared (n = 120), sterilized and pretreated for 1 or 4 weeks with the clinically used concentration of DAP (500 mg/mL), low concentrations of DAP (1, 5 or 50 mg/mL) loaded into a methylcellulose system, calcium hydroxide (Ca(OH)2), or placebo paste. After the assigned treatment time, treatment pastes were rinsed off and the samples were kept independently in phosphate buffered saline for 3 weeks. Pretreated dentin samples were then inoculated with Enterococcus faecalis and bacterial biofilms were allowed to grow for an additional 3 weeks. Biofilms were then retrieved from dentin using biofilm disruption assays, diluted, spiral plated, and quantified. Fisher’s Exact and Wilcoxon rank sum tests were used for statistical comparisons (α=0.05). Results Dentin pretreatment for 4 weeks with 5, 50 or 500 mg/mL of DAP demonstrated significantly higher residual antibiofilm effects and complete eradication of E. faecalis biofilms in comparison to a 1 week pretreatment with similar concentrations. However, dentin pretreated with 1 mg/mL of DAP or Ca(OH)2 did not provide a substantial residual antibiofilm effect regardless of the application time. Conclusions Dentin pretreatment with 5 mg/mL of DAP or higher for 4 weeks induced significantly higher residual antibiofilm effects in comparison to a 1 week pretreatment with the same concentrations.enPublisher Policydouble antibiotic pastecalcium hydroxideantibacterial effectArticle