homayon alaghemand

Since recurrent caries are one of the major causes of failure in resin restorations، the production of antibacterial resin composites was always under investigation. The aim of this study was to evaluate the efficacy of fissure sealants containing nanosilver particles against the Streptococcus mutans. In this experimental study، the antibacterial properties of two sealants (with fluoride (Clinpro 3M) and without fluoride (Concise 3M) was investigated with 0، 0. 01، 0. 02، 0. 03، 0. 04، 0. 05% w/w after adding nano-silver using direct contact test. Sealants formed on the walls of 500ml micro tube and after curing، they left in contact with bacterial suspension. In periods of 3، 24، 48h، a 10 µl volume of liquid medium was placed in blood agar culture and after 24 h incubation at 37ºC، the number of S. mutans colony was counted by colony counter. Data were analyzed using ANOVA and T-test. Results reported sealants with fluoride comparing to non fluoride ones had significant effect on inhibition of S. mutans growth (P<0. 001). The direct contact test demonstrated that by increasing the amount of nano particles، the bacterial growth was significantly diminished (P<0. 001). While sealants with fluoride demonstrated antibacterial effect، sealants with incorporation of higher weight percentage of nanosilver particles، had stronger and more significant antibacterial effect in direct contact test.

Before the resin bond endodontic post-cementation, various solutions are used to improve bond strength of these posts to root dentine. The purpose of this study was to evaluate the effect of the different pre-treatments (ethanol, ethylene de amine tetra acetic acid [EDTA] and EDTA + ethanol) on the bond strength of adhesively lutted tooth colored fiber post. Forty-eight human anterior teeth (incisor and canine) were selected in this experimental study. The species were endodontically treated, and the post-space was prepared. The species were randomly divided into four groups of 12 teeth in each and were treated as follows: (i) 0.1 M EDTA, (ii) 99.6% ethanol, (iii) 0.1 M EDTA followed by 99.6% ethanol and (iv) without any treatment (control). A push-out test was carried out after 24 h. Each tooth was cut into three 1 mm-thick sections. Fracture type was assessed using stereomicroscope. The data were analyzed by one way-ANOVA followed by Scheffe post-hoc test at P = 0.05. Almost, in EDTA and (EDTA + ethanol) every sample failed at the interface between post and lutting cement. Predominant failure mode in ethanol and control group was mixed failure. The surface treatment methods did not have any significant effect (P > 0.05) on any group but EDTA group had the highest bond strength. Surface treatment with (ethanol, EDTA, and EDTA + ethanol) does not significantly appear to be effective in improving the bond strength of fiber posts into root dentine. The highest bond strength was observed in EDTA group and the lowest in the control group.