Paknahad Maryam, Khaleghi Iman, Mortazavi Seyed Mohammad Javad
Department of Oral and Maxillofacial Radiology, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Front Dent. 2024 Apr 27;21:15. doi: 10.18502/fid.v21i15.15393. eCollection 2024.
This study aimed to evaluate radiofrequency-induced heating of different amalgam restorations and dental implants during 1.5T magnetic resonance imaging (MRI). Standardized class I cavities (5 mm long, 3 mm wide, and 3 mm deep) were prepared on the occlusal surface of 45 extracted human third molars. The samples were restored by three different types of amalgam including Cinalux amalgam (non-gamma-2, spherical), GS-80 (non-gamma-2, admix), and GK-110 amalgam (non-gamma-2, admix in silver). As a separate intervention group (G4), five titanium mini drive-lock implants with 2mm diameter and 10mm length were also selected and mounted to the base of the Eppendorf tube with 3mm of the implants extending above the mounting putty. The box containing the specimens was placed parallel to the long axis of the standard head and neck coil of the MRI device (64MHz radio-frequency energy with 25kW amplifier, 1.5T). Temperature fluctuations of the metallic materials in each group were monitored during MRI scans using a calibrated thermometer. One-way ANOVA was used to compare temperature changes among the amalgam groups (P<0.05). Temperature elevations ranged from 0.21°C to 0.70°C in amalgam restorations and from 0.35 to 0.47°C in dental implants. The temperature changes among the three amalgam agents were not statistically significant. According to our findings, the radiofrequency-induced heating of amalgam restorations and dental implants during MRI examination can be considered within acceptable ranges. Therefore, amalgam restorations and dental implants can be categorized as "MR safe" in terms of radiofrequency-induced heating during 1.5 T MRI.
本研究旨在评估在1.5T磁共振成像(MRI)过程中,不同汞合金修复体和牙种植体的射频感应加热情况。在45颗拔除的人类第三磨牙的咬合面上制备标准化的I类洞形(长5mm、宽3mm、深3mm)。样本用三种不同类型的汞合金进行修复,包括Cinalux汞合金(非γ-2,球形)、GS-80(非γ-2,混合型)和GK-110汞合金(非γ-2,银基混合型)。作为一个单独的干预组(G4),还选择了5颗直径2mm、长度10mm的钛微型驱动锁定种植体,并将其安装到Eppendorf管底部,种植体有3mm伸出安装油灰之上。装有标本的盒子与MRI设备的标准头颈线圈的长轴平行放置(64MHz射频能量,25kW放大器,1.5T)。在MRI扫描期间,使用校准温度计监测每组金属材料的温度波动。采用单因素方差分析比较汞合金组之间的温度变化(P<0.05)。汞合金修复体的温度升高范围为0.21°C至0.70°C,牙种植体的温度升高范围为0.35°C至0.47°C。三种汞合金制剂之间的温度变化无统计学意义。根据我们的研究结果,在MRI检查期间,汞合金修复体和牙种植体的射频感应加热可被认为在可接受范围内。因此,就1.5T MRI期间的射频感应加热而言,汞合金修复体和牙种植体可归类为“MR安全”。