title: The influence of canal curvature on the mechanical efficacy of root canal irrigation in vitro using real-time imaging of bioluminescent bacteria.
abstract: There are no quantitative data on the mechanical efficacy of irrigation in the removal of bacteria from curved canals. This study quantitatively analyzed the effects of root canal curvature and preparation size on the mechanical efficacy of irrigation using 33 mandibular single-rooted bicuspids allocated to groups according to root canal curvatures, group 1 (straight) 4 to 8 degrees, group 2 (intermediate curvature) 15 to 19 degrees, and group 3 (greatest curvature) 24 to 28 degrees. Teeth were sequentially instrumented to sizes 27/.04, 36/.04, and 46/.04 using a crown-down technique. Suspensions of the bioluminescent reporter strain Pseudomonas fluorescens 5RL (1.5 x 10(6) cells) were inoculated into canals of sterilized teeth after each sequential instrumentation. Canals were irrigated with 6 ml of irrigant delivered 1 mm from working length using a 30-gauge needle. Remaining bacteria were quantified using real-time bioluminescent imaging. Irrigation was significantly less effective in 24 to 28 degrees curvature canals prepared to size 27/.04 compared to 46/.04 (p < 0.007, repeated-measures ANOVA).
authors.affiliation: Department of Cariology, Restorative Sciences and Endodontics, University of Michigan, School of Dentistry, Ann Arbor, Michigan 48409-1078, USA.
authors.forename: Donald
authors.initials: D
authors.lastname: Nguy
authors.forename: Christine
authors.initials: C
authors.lastname: Sedgley
mesh_terms: D001641:Bicuspid; D002614:Chelating Agents / Q000627:therapeutic use; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000382:microbiology; D004492:Edetic Acid / Q000627:therapeutic use; D006801:Humans; D007091:Image Processing, Computer-Assisted; D049449:Luminescence; D011551:Pseudomonas fluorescens / Q000166:cytology*; D019252:Radiography, Dental, Digital; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013053:Spectrophotometry
chemical_list: D002614:Chelating Agents; D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite