title: Photonic real-time monitoring of bacterial reduction in root canals by genetically engineered bacteria after chemomechanical endodontic therapy.
abstract: Microbial infection plays an important role in the development of pulp necrosis and formation of periapical lesions. In vitro and in vivo research in this field, traditionally microbiological culture methods using paper point sampling and quantitative culture, faces difficulties in completely removing bacteria from the root canal system and analyzing sequential procedures. This study employed genetically engineered bioluminescent bacteria and a light-sensitive imaging system to allow real-time visualization of the infection. Ten extracted teeth incubated with P. aeruginosa were treated by mechanical instrumentation with K-files (#30 K-file, #35 K-file and #40 K-file) and chemical irrigation with sodium hypochlorite and hydrogen peroxide. Irrigation alone reduced the contamination in 18%; the first chemomechanical sequence (instrumentation with a #30 K-file + irrigation) provided 41% of reduction; the second sequence (#35 K-file + irrigation) achieved 62%; and the complete therapy (#30 K-file + #35 K-file + #40 K-file + irrigation) achieved 93% of bacterial reduction. These results suggest that the endodontic treatment is dependent on the association of a chemical and mechanical approaches and that root canal enlargement improves bacterial reduction probably because the irrigation has more access to the apical third.
authors.affiliation: Center of Lasers and Applications, IPEN-CNEN, São Paulo, Brazil. garcez.segundo@terra.com.br
authors.forename: Aguinaldo Silva
authors.initials: AS
authors.lastname: Garcez
authors.forename: Silvia Cristina
authors.initials: SC
authors.lastname: Nunez
authors.forename: José Luis
authors.initials: JL
authors.lastname: Lage-Marques
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.forename: Martha Simões
authors.initials: MS
authors.lastname: Ribeiro
mesh_terms: D015169:Colony Count, Microbial / Q000379:methods*; D003481:Cuspid; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004202:Disinfectants / Q000494:pharmacology; D004338:Drug Combinations; D005818:Genetic Engineering; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007180:Incisor; D008163:Luminescent Measurements / Q000379:methods; D008164:Luminescent Proteins / Q000378:metabolism; D008437:Maxilla; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012388:Root Canal Irrigants / Q000494:pharmacology*; D018915:Root Canal Preparation / Q000379:methods*; D012680:Sensitivity and Specificity; D012973:Sodium Hypochlorite / Q000494:pharmacology
chemical_list: D004202:Disinfectants; D004338:Drug Combinations; D008164:Luminescent Proteins; D012388:Root Canal Irrigants; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite