Electrochemistry of calcium precipitating bacteria in orthodontic wire

BackgroundCalculus composed of inorganic and organic components with bacteria formed on teeth gets deposited on orthodontic wires. The reason for calculus formation and impact of calcium precipitating bacteria (CPB) on orthodontic wire were studied. A pilot study on electrochemical characterization of CPB on orthodontic wires was done.MethodsCPB were isolated from orthodontic patients and identified by molecular techniques. The electrochemical behavior of two isolates (CPB-1 and CPB-3) on orthodontic wires was studied by employing polarization and impedance techniques. The CPB morphology by scanning electron microscopy and chemical characterization of CPB and tooth pulp stone were studied by Fourier transform infrared (FTIR) and X-ray diffraction (XRD).ResultsThe two isolates Bacillus megaterium (CPB-1) and Paenibacillus sp. (CPB-3) identified with 16S rRNA sequencing method increased pH of B4 medium from 5.32 to 8.3. The carboxylic acid and phosphate groups identified in FTIR analysis acted as nucleation sites for calcium deposition. The biogenic crystal phases identified in teeth pulp stone by XRD were similar to bacterial isolates cultured in the laboratory. The electrochemical studies with two CPB species revealed that biogenic calcium phosphate species act as cathodic inhibitors on orthodontic wire.ConclusionThe present study concluded that teeth pulp stone formation is due to CPB and high pH determines the mineralization process. Diffusion process and dispersive capacitive behavior indicate that the chloride ions may penetrate through calcium deposits and initiate pitting corrosion on orthodontic wire which may enhance the leaching of toxic elements in saliva.