title: Permeability of the root canal wall and occlusion of dentinal tubules by Ag(NH3)2F: a comparison of combined use with pulsed Nd:YAG laser or iontophoresis.
abstract: OBJECTIVE
  We used SEM-EDX and the Vickers hardness test to compare the penetration and hardness of silver resulting from use of either (i) pulsed Nd:YAG laser or (ii) iontophoresis, after root canal wall shaping using the standard method of coating with 38% Ag(NH3)2F solution.
  
  
  BACKGROUND
  There have not been any reports of penetration and hardness following the application of Ag(NH3)2F solution together with laser or iontophoresis.
  
  
  METHODS
  We used 21 extracted human single-rooted teeth randomly divided into three groups. Group 1 was coated with Ag(NH3)2F, Group 2 was irradiated with a Nd:YAG laser after coating with Ag(NH3)2F solution, and Group 3 was iontophoresised after coating. Then we observed the permeability of silver through the root canal wall using SEM-EDX.
  
  
  RESULTS
  The results show that iontophoresis after coating with Ag(NH3)2F solution (Group 3) resulted in the greatest and deepest penetration of silver into the root canal wall. There was no significant difference between teeth in Groups 1 and 2. For the hardness test, the 21 teeth were tested using SEM-EDX test, 7 untreated teeth were used as a control. The results show that Group 2 (laser treatment) teeth were the hardest.
  
  
  CONCLUSIONS
  We therefore propose that root canals should be treated using irradiation with an Nd:YAG laser that has been coated with Ag(NH3)2F solution and that this method provides better results than either iontophoresis after coating, or coating alone.
authors.affiliation: Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan. keikoyo@rr.iij4u.or.jp
authors.forename: K
authors.initials: K
authors.lastname: Yokoyama
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: J
authors.initials: J
authors.lastname: Murase
mesh_terms: D003131:Combined Modality Therapy; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D003806:Dentin Permeability / Q000187:drug effects* / Q000528:radiation effects*; D003808:Dentin Solubility / Q000187:drug effects* / Q000528:radiation effects*; D004353:Drug Evaluation, Preclinical; D005460:Fluorides, Topical; D006245:Hardness Tests; D006801:Humans; D007478:Iontophoresis / Q000379:methods*; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D000644:Quaternary Ammonium Compounds / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D011897:Random Allocation; D018915:Root Canal Preparation; D018030:Silver Compounds; D013052:Spectrometry, X-Ray Emission
chemical_list: D005460:Fluorides, Topical; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; C024633:silver diamine fluoride