title: Effect of propolis gel on the in vitro reduction of dentin permeability.
abstract: OBJECTIVE
  The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro.
  
  
  METHODS
  The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9). The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM) at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level.
  
  
  RESULTS
  Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05). The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis.
  
  
  CONCLUSIONS
  Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity.
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Community Health, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. shcperes@usp.br
authors.forename: Silvia Helena de Carvalho
authors.initials: SH
authors.lastname: Sales-Peres
authors.forename: Flávia Negreiros de
authors.initials: FN
authors.lastname: Carvalho
authors.forename: Juliane Avansini
authors.initials: JA
authors.lastname: Marsicano
authors.forename: Maria Cecília
authors.initials: MC
authors.lastname: Mattos
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Pereira
authors.forename: Moacir Rossi
authors.initials: MR
authors.lastname: Forim
authors.forename: Maria Fatima das Graças Fernandes da
authors.initials: MF
authors.lastname: Silva
mesh_terms: D000704:Analysis of Variance; D002327:Cariostatic Agents / Q000737:chemistry / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D057133:Dentin Desensitizing Agents / Q000737:chemistry; D003806:Dentin Permeability / Q000187:drug effects*; D005459:Fluorides / Q000737:chemistry / Q000494:pharmacology*; D005782:Gels; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D010070:Oxalates / Q000737:chemistry / Q000494:pharmacology*; D011429:Propolis / Q000737:chemistry / Q000494:pharmacology*; D016369:Smear Layer; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D002327:Cariostatic Agents; D057133:Dentin Desensitizing Agents; D005782:Gels; D010070:Oxalates; D014867:Water; D011429:Propolis; D005459:Fluorides