title: Longitudinal study on the influence of Nd:YAG laser irradiation on microleakage associated with two filling techniques.
abstract: OBJECTIVE
  This study investigates the effects of Nd:YAG laser irradiation on apical and coronal seals, when used prior to two root canal filling techniques.
  
  
  BACKGROUND
  Limited information exists regarding the effects of morphologic changes to dentin walls following Nd:YAG laser irradiation on the sealing ability of root fillings.
  
  
  METHODS
  Two hundred forty teeth were analyzed by observing coronal and apical leakage of Indian ink (DL), and 60 were analyzed for through-and-through leakage using the fluid transport model (FTM). The Nd:YAG laser parameters were 1.5 W, 100 mJ, and 15 Hz (four times for 5 s at 20 s intervals). Each group consisted of a lased and a nonlased subgroup: each subgroup had root fills done by either cold lateral condensation (CLC) or hybrid condensation (HC). Leakage was assessed after 48 h, and then at 1, 6, and 12 months. The DL group was divided into four groups of 15 teeth for each evaluation point. Through-and-through leakage (L in microliters/day) was measured for 48 h under a pressure of 1.2 atm using FTM, and recorded as L = 0 (L1), 0 < L <or= 10 (L2), or L > 10 (L3).
  
  
  RESULTS
  Apical and coronal dye leakage was observed in all groups. Significant differences (p < 0.05) in apical leakage were found between HC and HC + Nd after 1, 6, and 12 months, and between CLC and CLC + Nd at 6 and 12 months. No significant differences were found between laser-irradiated and non-laser-irradiated groups with FTM.
  
  
  CONCLUSIONS
  Pulsed Nd:YAG laser irradiation following root canal preparation may reduce apical leakage in association with hybrid gutta-percha condensation.
authors: Department of Operative Dentistry and Endodontology, Ghent Dental Laser Center, Dental School, Ghent University, Gent, Belgium.
authors: Maarten
authors: M
authors: Meire
authors: Athina
authors: A
authors: Mavridou
authors: Nikolaas
authors: N
authors: Dewilde
authors: Geert
authors: G
authors: Hommez
authors: Roeland Jozef Gentil
authors: RJ
authors: De Moor
mesh_terms: D003763:Dental Leakage / Q000209:etiology*; D003804:Dentin / Q000528:radiation effects*; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D053844:Lasers, Solid-State; D008137:Longitudinal Studies; D028022:Low-Level Light Therapy / Q000009:adverse effects*; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D018915:Root Canal Preparation; D012390:Root Canal Therapy / Q000009:adverse effects* / Q000379:methods*
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha