title: Quantification of cultivable bacteria and endotoxin in post-treatment apical periodontitis before and after chemo-mechanical preparation.
abstract: This clinical study was conducted to quantify cultivable bacteria and endotoxin in root canals with post-treatment apical periodontitis by correlating their levels with clinical features and to evaluate the effect of chemo-mechanical preparation (CMP) with 2 % chlorhexidine gel + 17 % EDTA on bacterial and endotoxin removal/elimination. Moreover, target strict Gram-negative anaerobic bacteria were investigated by polymerase chain reaction (PCR). Fifteen teeth with post-treatment apical periodontitis were sampled before (s1) and after (s2) CMP. Culture techniques determined the number of colony-forming units (CFU). PCR (16S rDNA) and limulus amebocyte lysate (LAL) assay were used for bacterial and endotoxin detection, respectively. Prevotella nigrescens (4/15), Prevotella intermedia (2/15), and Tannerella forsythia (2/15) were the most frequently detected species. Endotoxin was recovered in 100 % of the samples. At s1, bacteria and endotoxin were detected at a median value of 5.14 × 10(3) CFU/mL and 3.96 EU/mL, respectively. Higher levels of endotoxin were related to a larger size of radiolucent area (>5 mm) (p < 0.05). CMP was more effective in reducing bacteria (99.61 %) than endotoxin (60.6 %) (both p < 0.05). Our findings indicated that the levels of endotoxin found in infected root canals were related to a larger size of radiolucent area in the periapical region. Moreover, CMP was effective in reducing both bacterial and endotoxin contents in post-treatment apical periodontitis.
authors.affiliation: Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School-State University of Campinas (UNICAMP), Piracicaba, SP, Brazil.
authors.forename: M S
authors.initials: MS
authors.lastname: Endo
authors.forename: F C
authors.initials: FC
authors.lastname: Martinho
authors.forename: A A
authors.initials: AA
authors.lastname: Zaia
authors.forename: C C R
authors.initials: CC
authors.lastname: Ferraz
authors.forename: J F A
authors.initials: JF
authors.lastname: Almeida
authors.forename: B P F A
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D058491:Bacterial Load / Q000379:methods*; D015373:Bacterial Typing Techniques / Q000379:methods; D002710:Chlorhexidine / Q000494:pharmacology*; D003786:Dental Pulp Cavity / Q000378:metabolism / Q000382:microbiology; D004492:Edetic Acid / Q000494:pharmacology; D004731:Endotoxins / Q000378:metabolism*; D006801:Humans; D050296:Microbial Viability; D010485:Periapical Periodontitis / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D018720:Prevotella / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D016896:Treatment Outcome; D014208:Treponema / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004731:Endotoxins; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D004492:Edetic Acid; D002710:Chlorhexidine