title: Removal of calcium hydroxide from Weine Type II systems using photon-induced photoacoustic streaming, passive ultrasonic, and needle irrigation: a microcomputed tomography study.
abstract: OBJECTIVE
  This study compared the effectiveness of Er:YAG laser-activated irrigation (PIPS), passive ultrasonic irrigation (PUI) with EndoUltra and standard needle irrigation (SNI) in the removal of calcium hydroxide [Ca(OH)2] from the mesial roots of Weine Type II mandibular molars.
  
  
  METHODS
  Thirty mandibular molars were screened by µCT for the presence of mesial roots with complex intra-canal anatomy and a common apical foramen. The teeth were enlarged to a standardized 25/.06 preparation and filled with Ca(OH)2 paste. Specimens were divided into three groups (n=10) according to the technique used for Ca(OH)2 removal: PIPS, at 15 Hz and 20 mJ using a 9 mm long, 600 µm diameter tip; PUI using a 15/.02 tip; and SNI (30 Ga. side-vented needle). Equal volumes of 8.25% NaOCl and 17% EDTA were used in all groups. µCT was used to measure the initial amount of Ca(OH)2 present and to assess the residual volume of Ca(OH)2 following each irrigation protocol. Data were analyzed using Tukey HSD and Kruskal-Wallis tests (α=5%).
  
  
  RESULTS
  The mean volume of Ca(OH)2 before removal was significantly higher in the coronal third than in the middle and apical third (p<0.001). Ca(OH)2 was similarly removed from the coronal and middle thirds with the three methods used (p>0.05). PIPS (median 0%; IQR: 0-0) showed significant higher Ca(OH)2 removal in the apical third than PUI (median 100%, IQR: 85-100) and SNI (median 47%; IQR: 16-72) (p<0.001).
  
  
  CONCLUSIONS
  PIPS laser-activation was more effective for the removal of Ca(OH)2 from mesial roots of mandibular molars with Weine Type II canal configurations than PUI with EndoUltra and SNI.
authors.affiliation: - University of Tennessee Health Science Center, College of Dentistry, Department of Endodontics, Memphis, TN, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Lloyd
authors.affiliation: - University of Tennessee Health Science Center, College of Dentistry, Department of Endodontics, Memphis, TN, USA.
authors.forename: Geraldine
authors.initials: G
authors.lastname: Navarrete
authors.affiliation: - University of Tennessee Health Science Center, College of Dentistry, Department of Endodontics, Memphis, TN, USA.
authors.forename: Melissa Andreia
authors.initials: MA
authors.lastname: Marchesan
authors.affiliation: - The University of Oklahoma, College of Dentistry, Oklahoma City, OK, USA.
authors.forename: David
authors.initials: D
authors.lastname: Clement
mesh_terms: D000704:Analysis of Variance; D002126:Calcium Hydroxide / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000187:drug effects; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use; D008963:Molar; D009339:Needles; D061088:Photoacoustic Techniques / Q000379:methods; D015203:Reproducibility of Results; D012388:Root Canal Irrigants / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D018709:Statistics, Nonparametric; D007507:Therapeutic Irrigation / Q000379:methods; D014464:Ultrasonic Therapy / Q000379:methods; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D012388:Root Canal Irrigants; D002126:Calcium Hydroxide