Effect of various amounts of nanosilver incorporation on the mechanical properties of resin modified glass-ionomer cement

  Background and Aims: Metallic nano-particles show exclusive biological, chemical and physical characteristic. The purpose of this research was to evaluate the effect of various amounts of nanosilver incorporation (0 (as control), 20, 40, 80, 120, 200 ppm) on the mechanical Properties ( compressive and flexural strength) of resin modified Glass ionomer Cement.   Materials and Methods: Based on ISO 4049 and ISO 9971 for polyalkenoid cements, 90 cases in each group were prepared for the flexural and compressive strength. Specimens in 6 groups with different amounts of nanosilver (20, 40, 80, 120 and 200 ppm) and control (Fuji II LC improved), stored in distilled water at 37 ° C for 1 day and 30 days. Flexural strength, using a three-point bending method, Modulus of elasticity and the compressive strength were measured by universal testing machine (Zwick) with crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey post HOC test.   Results: The flexural strength and modulus of various amounts of nanosilver incorporation of resin modified glass-ionomer cement were not significantly different (P>0.05). The compressive strength of incorporating of20 ppm compared with control (P=0.01), 40 ppm (P=0.02) and 80 ppm compared with control (P<0.001) were increased. The flexural strength and compressive strength of Fuji II LC, containing nanosilver particles were increased after 1 day and 1 month significantly (P<0.001).   Conclusion: Incorporation of 20 to 80 ppm nanosilver into Fuji II LC had increased mechanical properties compared to the original cement

Evaluation of parental knowledge, attitudes and practices in preschool children on importance of primary teeth and some related factors among subjects attending Semnan University of Medical Sciences dental clinic

Introduction: Knowledge is a necessary component for behavioral changes, including behaviors related to oral health and oral disease prevention. Families have the most important role in children's teeth and mouth hygiene. This study aimed to determine parental knowledge, attitudes and practices in preschool children on importance of primary teeth and some related factors among subjects referred to the dental clinic in Semnan University of Medical Sciences (SUMS). Materials and Methods: This was a descriptive and cross-sectional study on 267 parents of preschool children reffering to the dental clinic of SUMS. Data was gathered by means of a questionnaire and interview. The questionnaire was composed of 22 parts including 21 multiple-choice questions and one open-ended question. Descriptive statistics containing frequency tables, mean, standard deviation, multiple and simple logistic regression tests was used. Results: About 51.1% of parents had low level knowledge and 48.9% had good knowledge and 60 percent of parents had a good practice. There was a significant relation between Lower economic status, attitudes and lower practice of parents (p<0.05). Conclusion: Educating parents regarding the importance of caring for primary teeth should be in line with the individual needs of children and parents to succeed in the prevention programs of oral diseases in children

Comparison of various concentrations of tricalcium phosphate nanoparticles on mechanical properties and remineralization of fissure sealants.

The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles.This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1-5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0-5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey's Post Hoc analysis/HSD were used to analyze the data.There was no significant difference between the flexural strengths/elastic modulus of the 0-5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (