Department of Physics, Bogazici University, Bebek, 34342, Istanbul, Turkey.
Kartal Dr. Lutfi Kirdar Education and Research Hospital, Ministry of Health, 34890, Istanbul, Turkey.
Radiat Oncol. 2020 Feb 17;15(1):38. doi: 10.1186/s13014-020-01486-7.
On the elastic profiles of human teeth after radiotherapy for head and neck cancers, generation of dental complications, which may bring several side effects preventing the quality of life, has not well clarified. Thus, we aimed to show the applicability of using 320 MHz Scanning Acoustic Microscopy (SAM) in the evaluation of the tooth damage acoustically at the micrometer level following radiation therapy, and also in the determination of the safe dose limits to impede severe dental damage.
This prospective study was performed by SAM employed at 320 MHz by an azimuthal resolution of 4.7 μm resolving enamel and dentin. A total of 45 sound human third molar teeth collected between September 2018 and May 2019 were used for the acoustic impedance measurements pre- and post irradiation. Nine samples for each group (control, 2 Gy, 8 Gy, 20 Gy, 30 Gy and 60 Gy) were evaluated to acquire the acoustic images and perform a qualitative analysis. Scanning Electron Microscopy (SEM) images were obtained to establish a relationship between micromechanical and morphological characteristics of the teeth. Statistical analysis was conducted using the Student t-test succeded by Mann-Whitney U investigation (p < .05), while SEM images were assessed qualitatively.
The analysis included 45 sound teeth collected from men and women 18 to 50 years old. Post irradiation micromechanical variations of human teeth were significant only in the radiation groups of 30 Gy and 60 Gy compared to pre-irradiation group for enamel (7.24 ± 0.18 MRayl and 6.49 ± 028 MRayl; p < 0.05, respectively). Besides, the teeth subjected to radiation doses of 20, 30 and 60 Gy represented significantly lower acoustic impedance values relative to non-irradiated group for dentin (6.52 ± 0.43 MRayl, 5.71 ± 0.66 MRayl and 4.82 ± 0.53 MRayl p < 0.05), respectively.
These results are evidence for a safe acoustic examination device which may be a useful tool to visualize and follow the safe dose limits to impede severe dental damage through the radiation therapy treatment for head and neck cancers.
在头颈部癌症放疗后的人牙弹性曲线上，可能会产生多种牙科并发症，从而带来一些副作用，影响生活质量，但这些并发症的产生机制尚未完全阐明。因此，我们旨在展示 320MHz 扫描声学显微镜（SAM）在评估放射治疗后牙齿微米级损伤的适用性，以及确定阻止严重牙齿损伤的安全剂量限制。
本前瞻性研究采用 320MHz 的 SAM，方位分辨率为 4.7μm，可分辨釉质和牙本质。共使用 45 颗收集于 2018 年 9 月至 2019 年 5 月之间的健康第三磨牙进行声阻抗测量，在照射前后进行评估。每组（对照组、2Gy、8Gy、20Gy、30Gy 和 60Gy）各有 9 个样本，用于获取声像并进行定性分析。还获得了扫描电子显微镜（SEM）图像，以建立牙齿的微机械和形态特征之间的关系。使用学生 t 检验（随后是曼-惠特尼 U 检验）进行统计分析（p<0.05），同时对 SEM 图像进行定性评估。
该分析包括 45 颗来自 18 至 50 岁男性和女性的健康第三磨牙。与照射前组相比，仅在 30Gy 和 60Gy 的照射组中，人牙的照射后微机械变化具有统计学意义，表现在釉质方面为 7.24±0.18MRayl 和 6.49±0.28MRayl（p<0.05）。此外，与未照射组相比，照射剂量为 20、30 和 60Gy 的牙齿的牙本质的声阻抗值显著降低，分别为 6.52±0.43MRayl、5.71±0.66MRayl 和 4.82±0.53MRayl（p<0.05）。
这些结果为安全的声学检查设备提供了证据，该设备可能是一种有用的工具，可通过对头颈部癌症的放射治疗来可视化和跟踪安全剂量限制，以阻止严重的牙齿损伤。
