title: Morphological and atomic analytical changes of root canal wall dentin after treatment with thirty-eight percent Ag(NH3)2F solution and CO2 laser.
abstract: OBJECTIVE
  The morphological and atomic analytical changes of the root canal wall dentin, treated with 38% diamine silver fluoride [Ag(NH3)2F] solution and irradiated by carbon dioxide (CO2) laser at the continuous wave mode were evaluated in vitro.
  
  
  BACKGROUND
  There has been no report on the morphological or atomic analytical changes of the effect of Ag(NH3)2F solution and CO2 laser on root canal walls.
  
  
  METHODS
  Eighty extracted human single-rooted teeth were instrumented using a conventional technique and randomly divided into 8 groups of 10 teeth each. The teeth in group 1 were neither treated with Ag(NH3)2F solution nor lased. Groups 2, 3, and 4 were irradiated by laser at the parameters of 1, 2, and 3 W for 10 seconds, respectively. Group 5 was treated with Ag(NH3)2F solution only. The other 3 groups were treated with Ag(NH3)2F solution and then lased by the same method as groups 2, 3, and 4. After this treatment, 4 specimens each from group 1, 5, and 6 were analyzed by scanning electron microscope-energy dispersive x-ray spectroscopy (SEM-EDX) and other specimens in all groups were examined by scanning electron microscopy (SEM).
  
  
  RESULTS
  The smear layer and debris of the control and lased specimens were not completely removed, but the areas of carbonization of evaporation of smear layer and open dentinal tubules were observed on the specimens treated with Ag(NH3)2F and lased at 1 W (group 6). After laser irradiation, the amount of silver on the root canal surfaces was significantly reduced to approximately one-third level on the measurement of SEM-EDX (p < 0.01).
  
  
  CONCLUSIONS
  These results suggest that CO2 laser is an effective method to remove or melt smear layer of root canal walls after treatment with 38% Ag(NH3)2F solution if an appropriate parameter is selected.
authors: Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan.
authors: J N
authors: JN
authors: Eto
authors: W
authors: W
authors: Niu
authors: F H
authors: FH
authors: Takeda
authors: Y
authors: Y
authors: Kimura
authors: K
authors: K
authors: Matsumoto
mesh_terms: D002245:Carbon Dioxide; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000528:radiation effects*; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects*; D005069:Evaluation Studies as Topic; D005460:Fluorides, Topical; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology; D018915:Root Canal Preparation / Q000295:instrumentation*; D018030:Silver Compounds; D016369:Smear Layer; D018709:Statistics, Nonparametric; D014092:Tooth Root / Q000187:drug effects / Q000528:radiation effects
chemical_list: D005460:Fluorides, Topical; D000644:Quaternary Ammonium Compounds; D012388:Root Canal Irrigants; D018030:Silver Compounds; D002245:Carbon Dioxide; C024633:silver diamine fluoride