Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials

Abstract

This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm(2) area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 degrees C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials.

Influence of Different Dentin Substrate (Caries-Affected, Caries-Infected, Sound) on Long-Term μTBS

“…Orthodontic looped wires and silicon hot glue were used to individually fix the teeth to the lid of glass vials immersing them in 40 mL sterile distilled water in order to be sterilized using gamma irradiation (GC-220E; MDS Nordion, Ottawa, Canada) for 32 h at 27 ºC with a 14.5 kGy total radiation dose (17). The teeth from groups Ca and Ci were relocated in a sterile second glass vial immersed in 40 mL sterile brain-heart infusion broth (BHI; Difco Laboratories, Detroit, MI, USA) supplemented with yeast extract (Himedia Laboratories, PVT Ltd., Mumbai, India), 0.5% glucose (Synth; LabSynth, São Paulo, SP, Brazil), 1.0% sucrose (Synth; LabSynth) and 2.0% S. mutans strain (UA159) for development of the artificial carious lesions.…”

Adhesion and Initial Colonization of Streptococcus mutans is Influenced by Time and Composition of Different Composites

“…This is the method of choice, once it sterilizes without high temperature and pressure, or neither chemical products or gases. This method also does not affect the antibacterial properties of resin dental materials (Carvalho et al, 2009).…”

Evaluation of three different decontamination techniques on biofilm formation, and on physical and chemical properties of resin composites

“…13 Gamma radiation can destroy or damage living cells, 16 causes degradation of materials by increasing the temperature of the polymer, and leads to increase of resins degree of conversion. 13,20 UV light has biocide effects (UVC: wavelength between 200 and 280 nm) 21,22 and is also used for the sterilization process, especially for heat sensitive materials. 22 Unlike chemical products, chemical residues or byproducts are avoided, and light is nonpolluting and environmentally friendly.…”

“…Farrugia et al stated that EtO affects the chemical and physical characteristics of some restorative materials . Gamma radiation can destroy or damage living cells, causes degradation of materials by increasing the temperature of the polymer, and leads to increase of resins degree of conversion …”