The effect of ionizing radiation on properties of fluoride-releasing restorative materials

Abstract

The purpose of this study was to evaluate the effect of ionizing radiation from high energy X-ray on fluoride release, surface roughness, flexural strength, and surface chemical composition of the materials. The study groups comprised five different restorative materials: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer, and Fuji IX GP. Twenty disk-shaped specimens (8x2 mm) for fluoride release and 20 bar-shaped specimens (25 x 2x 2 mm) for flexural strength were prepared from each material. Each material group was divided into two subgroups: irradiated (IR) and non-irradiated (Non-IR). The specimens from IR groups were irradiated with 1.8 Gy/day for 39 days (total IR = 70.2 Gy). The amount of fluoride released into deionized water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours and on days 2, 3, 7, 15, 21, 28, 35, and 39 (n = 10). The flexural strength was evaluated using the three-point bending test (n = 10). After the period of measurement of fluoride release, seven specimens (n = 7) from each group were randomly selected to evaluate surface roughness using AFM and one specimen was randomly selected for the SEM and EDS analyses. Data were analyzed with two-way ANOVA and Tukey tests (p = 0.05). The irradiation significantly increased fluoride release and surface roughness for Amalgomer CR and Zirconomer groups (p < 0.05). No significant change in flexural strength of the materials was observed after irradiation (p > 0.05). The ionizing radiation altered the amount of fluoride release and surface roughness of only Amalgomer CR and Zirconomer. The effect could be related to the chemical compositions of materials.

Influence of Ionizing Radiation on Fluoride-Releasing Dental Restorative Materials

“…Conflicting results were reported by Lima et al, who found a significant increase in surface roughness due to radiotherapy in composites, glass ionomers, and resin-modified glass ionomers [ 37 ]. In a study by Ugurlu et al, Ra was investigated by atomic force microscopy, and radiation had no effect on a conventional glass ionomer and a giomer; however, a significant increase in Ra was observed for ceramic- and zirconia-reinforced glass ionomers, which was explained by increased absorption of radiation by the reinforcing fillers [ 38 ]. Our results for the Ra parameter showed that the surface roughness remained statistically similar for most materials after the 35-day period, regardless of exposure to radiotherapy.…”

Effects of ionizing radiation on surface properties of current restorative dental materials

“…In clinical conditions, dental materials and tooth restorations are exposed to radiotherapy in the presence of saliva. However, the specimens were stored in distilled water in this study following previous investigations [24,29,47,48]. Clinical variables associated with individual biology or oral hygiene such as hyposalivation, caries appearance, and longevity of restorative materials were not evaluated and, therefore, need to be evaluated in further clinical trials.…”

Mechanical properties of composites with bioactive technology Giomer: a literature review

“…The effect of ionizing radiation from X-rays with high energy does not seem to interfere with the flexural properties of restorative materials, especially for the giomer that has shown a higher flexural strength value when compared to glass ionomer cements and a carbomer. In addition, the flexural strength was not influenced by the surface roughness of the materials (Ugurlu, Ozkan, Ozseven, 2020). When subjected to dry and wet conditions, the material presented a flexural strength value superior to that of other bioactive resin, to the ionomer modified by resin and to compomers, being considered the most stable material among those studied (Garoushi, Vallittu, Lassila, 2018).…”