Bacterial reduction with nickel-titanium rotary instrumentation.
The purpose of this study was to compare intracanal bacterial reduction on teeth instrumented with 0.04 tapered nickel-titanium (NiTi) rotary instrumentation to bacterial reduction when using a stainless-steel K-file step-back technique using sterile saline irrigation. Forty-eight patients with apical periodontitis were randomly assigned treatment type. The canals were sampled before, during, and after instrumentation. The samples were incubated anaerobically for 7 days at 37 degrees C, colony-forming unit numbers calculated, and a log transformation performed to normalize the counts. Teeth exhibiting apical periodontitis were uniformly infected, whereas vital control teeth were not. A similar and uniform reduction occurred with progressive filing, regardless of technique (p < 0.0001). There was no detectable difference in colony-forming unit count after NiTi rotary or stainless-steel hand instrumentation (p = 0.42). Neither technique could predictably render canals free of bacteria. The results of this study indicate NiTi rotary and stainless-steel hand K-file step-back instrumentation techniques were not significantly different in their ability to reduce intracanal bacteria.
Dalton
B C
BC
Department of Orthodontics, University of North Carolina School of Dentistry, Chapel Hill 27599, USA.
Orstavik
D
D
Phillips
C
C
Pettiette
M
M
Trope
M
M
D000704:Analysis of Variance; D001419:Bacteria / Q000302:isolation & purification; D015169:Colony Count, Microbial; D003755:Dental High-Speed Technique; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004867:Equipment Design; D006801:Humans; D009532:Nickel; D010485:Periapical Periodontitis / Q000382:microbiology; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013193:Stainless Steel; D014025:Titanium
C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium