BackgroundDental caries are the most common mouth infectious disease and also chronic disease of childhood. Saliva plays different roles in oral cavity; for example, salivary immunoglobulins play significant role in body and oral immunity. Various studies were conducted on the different effects of IgA on oral cavity, especially dental caries, and reported controversial results. The current study aimed to compare salivary IgA level at different stages of dental caries in adults.Material and MethodsA total of 40 adults, aged 20 to 40 years, referred to the department of oral medicine at Qazvin Faculty of Dentistry, were selected voluntarily based on the number of decayed teeth. Their unstimulated saliva was collected by the spitting method. The cases were assigned to 4 groups each of 10, based on the number of decayed teeth, as follows: Group 1: Caries free, Group 2: With 1 or 2 decayed teeth, Group 3: With 3 or 4 decayed teeth, and Group 4: With 5 or more decayed teeth. None of the cases had systemic diseases or the history of using medicines which affect the quality or quantity of saliva. The salivary IgA level of the cases was measured immunoturbidometrically and analyzed by ANOVA and t test.ResultsSignificant difference was observed between the groups 1 and 4, but there was no significant difference between the other groups.ConclusionsAccording to the results of the current study, the salivary IgA can be considered as an index for the function of immune system, which may be increased by the number of decayed teeth. In fact, the increase of salivary IgA is just the response of immune system to the accumulation of microorganisms and may be the attempt of body to control them. Key words:Saliva, IgA, Dental caries.

BackgroundThe study aims to investigate the effect of incorporation of sepiolite nanoparticles on the microtensile bond strength of an experimental dentin bonding to the human dentin.Material and MethodsThe sepiolite nanoparticles were incorporated into an experimental methacrylate-based dentin bonding system in concentrations of 0.0, 0.2, 1.0, 2.0, and 5.0 weight percents. The specimens were then ultrasonicated to finely disperse the nanoparticles in the adhesive matrix. The coronal enamel of 30 intact human premolars was cut to expose dentin. Having etched, rinsed, and blot dried the experimental bonding agents were applied to dentin surface. Adper Single Bond was used as control group according to the manufactor’s instruction. Then all the teeth were built up by composite and sectioned in stick form for microtensile test. The fracture surface was observed using SEM. The data were analyzed by ANOVA and Tukey’s post-Hoc test.ResultsThe results indicated that the incorporation of the nanofiller, improved the bond strength to dentin with the highest values obtained at 1 w% sepiolite nanoparticle content.ConclusionsSepiolite nanoparticles can be considered as novel fillers to improve the mechanical properties of dentin bonding agents. Key words:Dentin bonding agent, nanoparticles, bond strength, sepiolite, microtensile test.