title: Effects of diode laser therapy and stannous fluoride on dentin resistance under different erosive acid attacks.
abstract: OBJECTIVE
  This in vitro study aimed to evaluate the effect of a low intensity diode laser (λ=808 nm; 60 J/cm2) associated with stannous fluoride on the inhibition of dentin erosion by assessing percentage of superficial hardness loss (%SHL) and calcium release into the acid solution.
  
  
  METHODS
  Human root dentin slabs were assigned to eight groups (n=10), according to treatments (control, stannous fluoride, diode laser therapy, and the combination of stannous fluoride and laser therapy), and acid challenge (hydrochloridric or citric acid). All slabs were subjected to a previous 2 h acquired pellicle formation; laser and fluoride treatments were performed according to the groups. Subsequently, the slabs were exposed to erosive challenge (0.01 M hydrochloridric acid or citric acid 1% for 60 sec). Additionally, calcium released into the acid solution during erosive challenge was analyzed by photometric test. Data were analyzed by ANOVA followed by Tukey's test (p<0.05).
  
  
  RESULTS
  Mean values (±SD) for %SHL of treated groups did not present statistically significant differences, regardless of the erosive challenge. However, in relation to released calcium concentration, groups treated with laser presented statistically significant lower calcium loss under hydrochloridric acid challenge (p<0.001). To groups under citric acid attack, only the combination of treatments (p=0.037) was able to show a protective effect on dentin.
  
  
  CONCLUSIONS
  Under the conditions of this study, 808 nm diode laser with or without stannous fluoride could effectively reduce dentin surface loss under both acid exposures. Only calcium concentration analysis was sensitive enough to measure the effects under the tested conditions.
authors.affiliation: 1 Post-graduation Program, Faculty of Pharmacy, Dentistry and Nursing, Federal University of Ceará , Brazil .
authors.forename: Vanara F
authors.initials: VF
authors.lastname: Passos
authors.forename: Mary Anne S
authors.initials: MA
authors.lastname: Melo
authors.forename: Francisco F C
authors.initials: FF
authors.lastname: Silva
authors.forename: Lidiany Karla A
authors.initials: LK
authors.lastname: Rodrigues
authors.forename: Sérgio L
authors.initials: SL
authors.lastname: Santiago
mesh_terms: D003804:Dentin / Q000187:drug effects; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D028022:Low-Level Light Therapy; D014002:Tin Fluorides / Q000494:pharmacology*; D002579:Uterine Cervical Erosion / Q000517:prevention & control*
chemical_list: D014002:Tin Fluorides