title: Evaluation of cleaning capacity and instrumentation time of manual, hybrid and rotary instrumentation techniques in primary molars.
abstract: OBJECTIVE
  To compare the cleaning effectiveness of manual, hybrid and rotary instrumentation techniques in primary molar teeth.
  
  
  METHODS
  Fifteen primary molars were selected. After endodontic access, the teeth were immersed in a medium containing Enterococcus faecalis and divided into three groups, according to the root canal instrumentation technique: group 1 - manual, group 2 - hybrid and group 3 - nickel-titanium (NiTi) rotary files. For microbiological evaluation, comparisons before and after instrumentation were performed using the paired Student's t-test. One-way anova complemented with the Student's t-test was used to compare the percentage of microbial reduction. Instrumentation time was evaluated by Kruskal-Wallis and Student-Newman-Keuls tests. Images obtained under scanning electron microscopy were analysed by three blinded examiners, and kappa statistics was used to evaluate calibration among examiners. The most frequent results among examiners were analysed using Kruskal-Wallis and Student-Newman-Keuls tests.
  
  
  RESULTS
  The hybrid technique required a significantly longer instrumentation time than the manual and rotary techniques (P < 0.05). All techniques tested were able to significantly reduce the number of E. faecalis (P < 0.05). The hybrid technique was associated with the highest intracanal bacterial reduction, with a statistically significant difference compared with manual instrumentation (P = 0.01). Manual instrumentation resulted in the lowest amount of debris and the highest amount of smear layer when compared with the rotary and hybrid techniques (P < 0.05). There was no difference between rotary and hybrid instrumentation in the removal of debris and smear layer.
  
  
  CONCLUSIONS
  The use of NiTi rotary files is an option for root canal instrumentation in primary teeth.
authors.affiliation: Department of Paediatric Dentistry, Catholic Pontifical University of Campinas, Campinas, Brazil. slpinho@puc-campinas.edu.br
authors.forename: S L
authors.initials: SL
authors.lastname: Pinheiro
authors.forename: G
authors.initials: G
authors.lastname: Araujo
authors.forename: I
authors.initials: I
authors.lastname: Bincelli
authors.forename: R
authors.initials: R
authors.lastname: Cunha
authors.forename: C
authors.initials: C
authors.lastname: Bueno
mesh_terms: D058491:Bacterial Load; D000077463:Carbamide Peroxide; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000382:microbiology* / Q000648:ultrastructure; D003804:Dentin / Q000382:microbiology; D013293:Enterococcus faecalis / Q000302:isolation & purification; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000382:microbiology* / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry; D010545:Peroxides / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014094:Tooth, Deciduous / Q000382:microbiology* / Q000648:ultrastructure; D014508:Urea / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D003722:Dental Alloys; D010545:Peroxides; D012388:Root Canal Irrigants; C040654:titanium nickelide; D000077463:Carbamide Peroxide; D009532:Nickel; D014508:Urea; D014025:Titanium; D012973:Sodium Hypochlorite