title: [Evaluation of root canal isthmus debridement efficacy of Er:YAG laser in combination with sodium hypochlorite].
abstract: OBJECTIVE
  To histologically evaluate the efficacy of sodium hypochlorite (NaClO) in combination with Er:YAG (erbium-doped yttrium aluminium garnet) laser in dissolving necrotic tissue and cleaning root canals as well as canal isthmuses.
  
  
  METHODS
  After scanned by cone-beam CT (CBCT), 50 well-prepared premolars with root canal isthmuses were selected and randomly assigned into 5 groups. They were subsequently subjected to different regimens as followed: group A-irrigated with 1% NaClO for 1 minute, group B- irradiated by Er:YAG laser at 0.5 W combined with 1% NaClO irrigation for 1 minute, group C- irradiated by Er:YAG laser at 1.0 W combined with 1% NaClO irrigation for 1 minute, group D- irradiated by Er:YAG laser at 2.0 W combined with 1% NaClO irrigation for 1 minute,group E- negative control. After histological preparation and staining, the cross-sections were evaluated for percentage of tissue removal from root canals and isthmuses. The cleanliness values were calculated using SPSS 13.0 software package.
  
  
  RESULTS
  The mean percentage of root canals in group A, B, C and D was 95.24%, 96.53%、97.63% and 98.22%, respectively, and the mean percentage of isthmuses was 16.50%, 51.48%, 52.56% and 53.83%, respectively. The mean percentage of root canal and isthmus cleanliness values were significantly higher in group B, C and D (P<0.05) than that in group A. There was no significant differences of root canal and isthmus cleanliness among group B, C and D.
  
  
  CONCLUSIONS
  Er:YAG laser combined with 1% NaClO irrigation may be used effectively in root canal and root canal isthmus cleanliness as a new method.
authors.affiliation: First Dental Department, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; Shanghai Key laboratory of Stomatology. Shanghai 200011, China. E-mail:nancy77hello@sina.com.
authors.forename: Meng-Qi
authors.initials: MQ
authors.lastname: Zhou
authors.forename: Hao-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Xiao
authors.forename: Jin
authors.initials: J
authors.lastname: Hong
mesh_terms: D054893:Cone-Beam Computed Tomography; D003646:Debridement; D003786:Dental Pulp Cavity; D006801:Humans; D053844:Lasers, Solid-State; D018915:Root Canal Preparation / Q000379:methods*; D012390:Root Canal Therapy; D012973:Sodium Hypochlorite
chemical_list: D012973:Sodium Hypochlorite