Federal University of Uberlândia, School of Dentistry, Department of Periodontology and Implantology, Uberlândia, MG, Brasil.
Federal University of Uberlândia, School of Dentistry, Department of Operative Dentistry and Dental Materials, Uberlândia, MG, Brasil.
J Appl Oral Sci. 2020 Sep 28;28:e20200191. doi: 10.1590/1678-7757-2020-0191. eCollection 2020.
This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant.
Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm3), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm2) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey's test and Student's t-test (α=0.05).
The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02).
Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.
本研究分析了电离辐射对种植体周围骨组织的骨微观结构和生物力学性能的影响。
20 只兔子接受了三个 Morse 锥形连接种植体：一个在左胫骨，两个在右胫骨。动物随机分为两组：未照射组（对照组）和照射组，照射组在植入后 2 周内单次照射 30Gy。植入后 4 周，处死动物，对每个实验的植入/骨标本进行检测。右胫骨的标本（n=10）通过微计算机断层扫描（micro-CT）检测测量皮质体积（CtV，mm3）、皮质厚度（CtTh，mm）和孔隙率（CtPo，%）。其他标本（n=10）通过动态压痕检测测量骨的弹性模量（E，GPa）和维氏硬度（VHN，N/mm2）。左胫骨的标本（n=10）进行了拔出试验，以计算失效载荷（N）、失效点的位移（mm）和界面刚度（N/mm）。在照射组中，进行了两次测量：靠近，在种植体表面周围 1mm 处，以及远离，在第一次测量的外部极限处 2.5mm 处。数据采用单因素方差分析、Tukey 检验和 Student's t 检验（α=0.05）进行分析。
靠近种植体表面的照射骨的弹性模量（E）、维氏硬度（VHN）、Ct.Th 和 Ct.V 值较低，而孔隙率（Ct.Po）值较高，与远离种植体的骨相比（P<0.04）。远离种植体表面的照射骨的 E、VHN 和 Ct.Th 值较低，而孔隙率（Ct.Po）值较高，与未照射骨相比（P<0.04）。未照射骨的失效载荷、位移和刚度值均高于照射骨（P<0.02）。
种植体中的电离辐射对种植体周围骨组织的微观结构和生物力学性能产生了负面影响，主要是在种植体表面附近。
