title: Endodontic retreatment: clinical comparison of reciprocating systems versus rotary system in disinfecting root canals.
abstract: BACKGROUND
  This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria in endodontic retreatment.
  
  
  METHODS
  Thirty endodontically treated teeth with post-treatment apical periodontitis were selected. The specimens were divided into three groups according to the system used: WaveOne (n = 10), Reciproc instrument (n = 10), and ProTaper Universal Retreatment system (n = 10). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts.
  
  
  RESULTS
  At baseline, endotoxins and cultivable bacteria were recovered from 100% of the root canal samples in a median value of 5.84 EU/mL and 4.98 × 10(3) CFU/mL, respectively. After CMP, no differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems-WaveOne [94.11%] and Reciproc [93.29%] and with rotary systems-ProTaper [94.98%] (P > 0.05). Both single-file reciprocating systems [WaveOne (98.27%) and Reciproc (99.54%)] and rotary system [ProTaper (98.73%)] were effective in reducing bacterial load (P > 0.05). Moreover, no differences were found among the systems tested.
  
  
  CONCLUSIONS
  The Reciproc and WaveOne reciprocating systems were as effective as the ProTaper system for removal of endotoxins and bacteria in endodontic retreatment.
  
  
  CONCLUSIONS
  All systems tested were effective to remove cultivable bacteria and endotoxin in endodontic retreatment. As no differences among systems were observed, it is possible to suggest that clinicians should choose the preferred technique to perform endodontic.
authors.affiliation: Department of Restorative Dentistry, Endodontics Division-UNESP-UNIV Estadual Paulista, São José dos Campos Dental School, São José dos Campos, São Paulo, Brazil, Frederico.martinho@fosjc.unesp.br.
authors.forename: Frederico C
authors.initials: FC
authors.lastname: Martinho
authors.forename: Lilian F
authors.initials: LF
authors.lastname: Freitas
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Nascimento
authors.forename: Aleteia M
authors.initials: AM
authors.lastname: Fernandes
authors.forename: Fabio R M
authors.initials: FR
authors.lastname: Leite
authors.forename: Ana P M
authors.initials: AP
authors.lastname: Gomes
authors.forename: Izabel C G
authors.initials: IC
authors.lastname: Camões
mesh_terms: D058491:Bacterial Load; D001938:Brazil; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D010485:Periapical Periodontitis / Q000628:therapy*; D019233:Retreatment; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation*; D019553:Tooth, Nonvital / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D012388:Root Canal Irrigants