Sulfate-Reducing Bacteria: Biofilm Formation and Corrosive Activity in Endodontic Files

Abstract

Aim This study describes the biofilm formation and the corrosive capacity of sulfate-reducing bacteria (SRB) on the metallic structure of used endodontic files. Methods Sulfate-reducing bacteria (SRB) (Desulfovibrio desulfuricans oral and Desulfovibrio fairfieldensis or D. desulfuricans environmental) were inoculated into the culture media (Postgate C culture medium or modified Postgate E culture medium). The biocorrosive potential of these bacteria will be an important component of a biopharmaceutical under development called BACCOR. Afterwards, four used endodontic files (UEFs) were separately inoculated into a specific culture media for 445 days at 30°C in an incubator. The four UEFs were placed in a scanning electron microscope (SEM) and analyzed by the energy-dispersive X-ray spectrometry (EDS). Results The confocal laser scanning microscopic images indicate the presence of biofilm in the four samples. The SEM and SEM-EDS revealed the presence of rough, irregular structures adhering along the metallic surface of the used endodontic files, suggesting a mature calcified biofilm with a high concentration of Ca, P, C, and S. Conclusion The formation of SRB biofilms on used endodontic files shows characteristics that may contribute to the biocorrosion of these files, and the results may also provide complementary data for a biopharmaceutical, which is still under development to assist in the removal of fractured endodontic files inside root channels.

Microbial Community Drivers in Anaerobic Granulation at High Salinity

“…This is in line to the relative hydrophilicity possessed by E. faecium in comparison to the microbial community members present in UASB reactors hydrophobic granules (Daffonchio et al, 1995). Other abundant bacterial groups detected in R4 (without tryptone) and previously associated with biofilms, rather than granules formation, were Thermovirga (Lenhart et al, 2014), Desulfovibrio (Heggendorn et al, 2018) and Marinobacterium (Erable et al, 2009).…”

Text-Mining to Identify Gene Sets Involved in Biocorrosion by Sulfate-Reducing Bacteria: A Semi-Automated Workflow

“…Other factors contributing to the corrosion process can be credited to the production of acetate creating an acidic environment due to the consumption of lactate or pyruvate by D. desulfuricans . Previous studies report that the production of hydrogen sulfide by SRB can act as a pitting (type of localized corrosion) activator, which can be further oxidized to thiosulfate (intermediate in sulfate reduction), which is an even more aggressive pitting activator [ 38 , 39 , 40 , 41 , 42 , 43 ]. This analysis could help us infer that by-products (acids) of substrate utilization and energy metabolism (sulfate reduction) are directly and indirectly involved in pitting metal surfaces and biocorrosion.…”

In-Vitro Assessment of the Corrosion Potential of an Oral Strain of Sulfate-Reducing Bacteria on Metallic Orthodontic Materials

“…A 60-day immersion period was chosen for the study based on the reports of Isa et al [ 17 ] that the SRB in anaerobic reactors were most active between 11 and 24 days after which the activity decreased with a reduction in sulfide production after 50 days as a supersaturation with FeS2 will inhibit the further corrosion of steel [ 18 ]. The corrosive property of SRB has been experimentally elicited by other authors like Heggendorn et al [ 4 , 19 ] who showed the biofilm interaction with the metallic surface of endodontic files and the consequent corrosion. The results of our study are in line with their study wherein we identified localized corrosion induced by SRB of genus Desulfovibrio in stainless steel brackets and wires, NiTi, TMA wires, and Titanium mini-implants.…”

“…These organisms which can cause microbial corrosion are actively involved in the initiation and acceleration of metal dissolution. In one particular literature, SRB’s corrosion potential was being used for dissolving the fractured files in root canals [ 4 ]. Since intraoral corrosion leaks out corrosive products like nickel ions in the oral cavity [ 5 ] and moreover alters the biomechanical properties of the metallic orthodontic materials [ 6 ] and SRB is prevalent in the oral cavity of even healthy patients [ 7 , 8 ], it is not only inquisitive but also imperative to study whether SRB in the oral cavity was capable of causing corrosion of metallic orthodontic materials.…”