Department of Advanced Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.
Department of Radiation Therapeutics and Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.
J Oral Sci. 2022 Oct 1;64(4):274-278. doi: 10.2334/josnusd.22-0167. Epub 2022 Sep 7.
This study investigates the attenuation of radiation doses by four materials, heat-polymerized, and self-polymerized polymethyl methacrylate (PMMA), putty-type, and injection-type polyvinyl siloxane (PVS) impression material. This in vitro study should aid in the selection of dental materials for radiotherapy prostheses, thereby minimizing the possibility of radiotherapy side effects.
Specimens of each type were fabricated as a 5 × 5 cm squares with a thickness of 10 mm. Heat-polymerizing PMMA, self-polymerizing PMMA, putty-type PVS impression material, and injection-type PVS impression material were selected. A calibration curve was created to determine the association of radiation doses and grayscale value. A linear accelerator was used to irradiate the specimens. The radiation doses above and below the materials were measured using radiochromic film dosimetry. After film irradiation, the pixel scale of color change was used to determine the radiation dose based on the created calibration curve. The results were exported to find average doses to calculate the percentage of the attenuated dose for a comparison of the four materials.
The average attenuated doses of heat-polymerizing PMMA, self-polymerizing PMMA, putty-type PVS, and injection-type PVS were 10.8%, 6.2%, 17.2%, and 14.2% respectively.
PVS showed higher attenuating radiation exposure compared with PMMA.
本研究旨在探讨四种材料（热聚合型和自聚合型聚甲基丙烯酸甲酯（PMMA）、油泥型和注射型聚硅氧烷（PVS）印模材料）对辐射剂量的衰减作用。本体外研究有助于选择用于放射治疗修复体的牙科材料，从而最大程度地降低放射治疗副作用的可能性。
将每种类型的样本制成 5×5cm 见方、厚 10mm 的正方形。选择热聚合型 PMMA、自聚合型 PMMA、油泥型 PVS 印模材料和注射型 PVS 印模材料。制作校准曲线以确定辐射剂量与灰度值之间的关系。使用线性加速器对样本进行照射。使用放射性色带胶片剂量测定法测量材料上方和下方的辐射剂量。胶片照射后，根据创建的校准曲线，使用颜色变化的像素比例确定辐射剂量。导出结果以找到平均剂量，计算四种材料之间的衰减剂量百分比。
热聚合型 PMMA、自聚合型 PMMA、油泥型 PVS 和注射型 PVS 的平均衰减剂量分别为 10.8%、6.2%、17.2%和 14.2%。
与 PMMA 相比，PVS 显示出更高的辐射暴露衰减能力。
