title: Effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals: an electrochemical study.
abstract: OBJECTIVE
  The purpose of this laboratory study was to evaluate the effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals using an electrochemical method.
  
  
  METHODS
  Forty extracted single-rooted teeth were selected and the anatomic crown of each tooth was removed. The specimens were randomly divided into four groups. In group 1, the root canals were prepared with K-files and irradiated with Nd:YAG laser (5 W, 20 Hz) via a 300 microns optical fibre. Then the root canals were obturated with laterally condensed gutta-percha and Pulp Canal Sealer EWT. In group 2, the root canals were treated with the same method as those of group 1 but without laser irradiation. In group 3, the root canals were prepared with ProFiles, laser irradiated and then obturated with vertically condensed gutta-percha and Pulp Canal Sealer EWT. In group 4, the root canals were treated with the same method as those of group 3 but without laser irradiation. The electric resistance between standard and experimental electrodes in the canals was measured over a period of 10 days.
  
  
  RESULTS
  At 2 h, groups 1 and 3 irradiated with laser had significantly less apical leakage than group 2 (P < 0.05). After 10 days, group 4 had the highest leakage, followed by groups 2, 1 and 3; the differences between the groups was statistically significant (P < 0.05).
  
  
  CONCLUSIONS
  Laser irradiation following root canal preparation reduced apical leakage following root canal obturation.
authors.affiliation: Department of Conservative Dentistry, Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. dsparkh@samsung.co.kr
authors.forename: D S
authors.initials: DS
authors.lastname: Park
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: H M
authors.initials: HM
authors.lastname: Yoo
authors.forename: T S
authors.initials: TS
authors.lastname: Oh
mesh_terms: D000538:Aluminum Silicates; D000704:Analysis of Variance; D003763:Dental Leakage / Q000145:classification*; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D017097:Electric Impedance; D004563:Electrochemistry; D004567:Electrodes, Implanted; D005336:Fiber Optic Technology / Q000295:instrumentation; D005500:Follow-Up Studies; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D053685:Laser Therapy; D009354:Neodymium; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012389:Root Canal Obturation; D018915:Root Canal Preparation / Q000295:instrumentation; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D012387:Root Canal Filling Materials; D009354:Neodymium; D015019:Yttrium; D006171:Gutta-Percha