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.

摘要 本研究旨在评估高能X射线电离辐射对修复材料的氟离子释放、表面粗糙度、抗弯强度及表面化学成分的影响。本次研究共纳入5种不同的修复材料：Beautifil II、GCP Glass Fill、Amalgomer CR、Zirconomer及Fuji IX GP。每种材料分别制备20个用于氟离子释放检测的圆盘状试样（8×2 mm），以及20个用于抗弯强度检测的棒状试样（25×2×2 mm）。每个材料组分为两个亚组：辐照组（IR）与非辐照组（Non-IR）。辐照组试样以1.8 Gy/天的剂量辐照39天，总辐照剂量为70.2 Gy。分别于24小时及第2、3、7、15、21、28、35、39天时，采用氟离子选择性电极与离子分析仪测量去离子水中的氟离子释放量（n=10）。抗弯强度采用三点弯曲试验进行评估（n=10）。氟离子释放检测周期结束后，从每个组中随机选取7个试样用于原子力显微镜（AFM，atomic force microscope）表面粗糙度检测，再随机选取1个试样用于扫描电子显微镜（SEM，scanning electron microscope）与能谱仪（EDS，energy dispersive X-ray spectroscopy）分析。数据采用双因素方差分析与Tukey检验进行分析（p=0.05）。结果显示，辐照可显著提升Amalgomer CR与Zirconomer组的氟离子释放量与表面粗糙度（p<0.05）。辐照后各材料的抗弯强度未出现显著变化（p>0.05）。电离辐射仅对Amalgomer CR与Zirconomer的氟离子释放量及表面粗糙度产生影响，该效应可能与材料的化学成分相关。