title: Effect of 1440-nanometer neodymium:yttrium-aluminum-garnet laser irradiation on pain and neuropeptide reduction: a randomized prospective clinical trial.
abstract: BACKGROUND
  The purpose of this study was to investigate the efficacy of a 1440-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on relieving pain in relation to the levels of inflammatory cytokine and neuropeptides in the root canal exudates of teeth with persistent symptomatic apical periodontitis.
  
  
  METHODS
  Forty teeth with persistent symptomatic apical periodontitis were randomly assigned to treatment groups: group L, intracanal irradiation of 1440-nm Nd:YAG laser with a 300-μm-diameter fiberoptic tip in addition to conventional root canal retreatment, and group C, conventional root canal re-treatment. The degrees of both spontaneous pain and the pain on percussion before and after treatment were recorded, and root canal exudate samples were collected to quantify the associated levels of substance P, calcitonin gene-related peptide (CGRP), and matrix metalloproteinase (MMP)-8 by immunoassay.
  
  
  RESULTS
  All of the measured parameters were significantly reduced in group L (P < .05), whereas the level of pain on percussion, CGRP, and MMP-8 were significantly reduced in group C (P < .05). The 1440-nm Nd:YAG laser had significantly better effect on the relief of pain on percussion and the reduction of substance P, CGRP, and MMP-8 levels. The visual analog scale scores of perceived pain correlated with pain-related neuropeptides and inflammatory cytokine levels in root canal exudates.
  
  
  CONCLUSIONS
  The 1440-nm Nd:YAG laser irradiation via fiberoptic tip to the teeth with persistent apical periodontitis provided promising consequences of pain and inflammation modulation.
authors: Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors: Yeon-Jee
authors: YJ
authors: Yoo
authors: Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors: Won-Jun
authors: WJ
authors: Shon
authors: Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors: Seung-Ho
authors: SH
authors: Baek
authors: Section of Endodontics, School of Dentistry, University of California at Los Angeles, Los Angeles, California.
authors: Mo K
authors: MK
authors: Kang
authors: Department of Conservative Dentistry, School of Dentistry, Pusan National University, Yangsan, Korea.
authors: Hyeon-Cheol
authors: HC
authors: Kim
authors: Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea. Electronic address: jimin525@snu.ac.kr.
authors: WooCheol
authors: W
authors: Lee
mesh_terms: D000328:Adult; D015740:Calcitonin Gene-Related Peptide / Q000528:radiation effects; D016207:Cytokines / Q000528:radiation effects; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D005122:Exudates and Transudates / Q000528:radiation effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018836:Inflammation Mediators / Q000528:radiation effects; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000295:instrumentation*; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000528:radiation effects; D008875:Middle Aged; D009479:Neuropeptides / Q000528:radiation effects*; D018377:Neurotransmitter Agents / Q000528:radiation effects; D055100:Optical Fibers; D010146:Pain / Q000532:radiotherapy*; D010147:Pain Measurement / Q000379:methods; D010474:Percussion; D010485:Periapical Periodontitis / Q000532:radiotherapy*; D011446:Prospective Studies; D019233:Retreatment; D013373:Substance P / Q000528:radiation effects; D014665:Vasodilator Agents / Q000528:radiation effects
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D014665:Vasodilator Agents; D013373:Substance P; C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8; D015740:Calcitonin Gene-Related Peptide
keywords: Fiber-optic tip; Nd:YAG laser; VAS; neuropeptides; pain