title: Preventive effect of tooth fracture by pulsed Nd:YAG laser irradiation with diamine silver fluoride solution.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate the preventive effect of pulsed Nd:YAG laser irradiation with 38% diamine silver fluoride [Ag(NH3)2F] solution for the fracture of endodontically treated teeth in vitro.
  
  
  BACKGROUND
  There have been no reports on the preventive effect of tooth fracture using Nd:YAG laser with Ag(NH3)2F solution.
  
  
  METHODS
  Twenty-eight human extracted teeth were used in this study. The teeth were randomly classified into four groups: control group, where tooth surfaces were not submitted to any treatment; group 1, where tooth surfaces were coated with 38% Ag(NH3)2F solution; group 2, where tooth surfaces were coated with Ag(NH3)2F solution and irradiated by pulsed Nd:YAG laser for 2 sec; and group 3, where tooth surfaces were coated with Ag(NH3)2F solution and irradiated by pulsed Nd:YAG laser for 10 sec. After preparation, shear tests were performed and the maximum load for the fracture was measured. Results were analyzed using the Scheffe test, and difference at p < 0.05 was considered significant.
  
  
  RESULTS
  The failure load for group 2 (mean, 182.5 kg) had the highest mean value and differed significantly from those for the control group (mean, 146.3 kg) and group 1 (mean, 147.1 kg; p < 0.05). The failure loads for groups 1 and 3 (mean, 150.0 kg) did not differ significantly from that for the control group (p > 0.05).
  
  
  CONCLUSIONS
  The results show that the application of 38% Ag(NH3)2F solution followed by pulsed Nd:YAG laser irradiation for 2 sec is useful for prevention of tooth fracture at endodontically treated teeth.
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: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: A
authors.initials: A
authors.lastname: Fujishima
authors.forename: T
authors.initials: T
authors.lastname: Miyazaki
mesh_terms: D005460:Fluorides, Topical; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D008963:Molar; D009354:Neodymium; D011336:Probability; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D011897:Random Allocation; D012016:Reference Values; D012680:Sensitivity and Specificity; D018030:Silver Compounds; D012996:Solutions; D014082:Tooth Fractures / Q000517:prevention & control*
chemical_list: D005460:Fluorides, Topical; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; D012996:Solutions; D009354:Neodymium; C024633:silver diamine fluoride