Weinlaender Michael, Beumer John, Kenney E Barrie, Lekovic Vojislav, Holmes Ralph, Moy Peter K, Plenk Hanns
Bone and Biomaterials Research, Institute for Histology and Embryology, Medical University of Vienna, Austria.
Int J Oral Maxillofac Implants. 2006 Mar-Apr;21(2):212-24.
Radiation therapy influence on bone healing around 3 types of endosseous dental implants in dogs was evaluated.
Implants with 3 different surfaces (A = machined commercially pure titanium screws, B = commercially pure titanium plasma spray-coated cylinders, C = hydroxyapatite [HA] -ceramic coated cylinders) were first implanted unilaterally into the right posterior edentulous mandibles of 7 dogs as nonirradiated controls. After 12 weeks without functional loading and after sequential fluorochrome labeling these implants were retrieved by block dissection. In this same surgery, implants were placed on the contralateral side. Three weeks postimplantation the implant-containing hemimandibles were Cobalt 60 irradiated with the biologic equivalent of 5,000 cGy. Twelve weeks postimplantation and after labeling these irradiated implants were retrieved at sacrifice. On scanning electron, light, and fluorescence microscopic images of undecalcified longitudinal ground sections of the implants with surrounding tissues, percent bone-to-implant contact (% BIC), bone formation, and remodeling were histometrically and subjectively evaluated.
Woven bone formation started 1 week after implantation at the implant interfaces on both the nonirradiated and the irradiated sides. Average BICs (total/cortical/spongious bone bed) of 26%/49%/36% for surface A, 46%/48%/64% for surface B, and 81%/83%/78% for surface C were observed. In the irradiated hemimandibles average BICs (total/cortical/spongious bone bed) were reduced to 11%/9%/4% for surface A, 43%/46%/43% for surface B, and 63%/85%/76% for surface C, with increased resorption of peri-implant bone and retarded bone formation after irradiation.
Reductions of total % BIC in all irradiated implants, though not statistically significant, were significant (P < or = .05) on implant surfaces A and B in the spongious bone bed.
Retarded bone formation on surfaces A and B in the spongious bone bed represented a more radiation-sensitive situation at the time of radiation onset compared to advanced bone formation and maturation at surface C.
评估放射治疗对犬类三种不同类型骨内牙种植体周围骨愈合的影响。
将具有三种不同表面的种植体（A = 机械加工的商业纯钛螺钉，B = 商业纯钛等离子喷涂圆柱体，C = 羟基磷灰石[HA]陶瓷涂层圆柱体）首先单侧植入7只犬的右侧后牙区无牙下颌骨，作为未照射对照组。在无功能负载12周并进行连续荧光标记后，通过整块解剖取出这些种植体。在同一手术中，将种植体放置在对侧。植入后3周，对含种植体的半侧下颌骨进行钴60照射，生物学等效剂量为5000 cGy。植入后12周并进行标记后，在处死动物时取出这些照射后的种植体。在对带有周围组织的种植体未脱钙纵向磨片进行扫描电子、光学和荧光显微镜观察时，从组织形态计量学和主观方面评估骨与种植体接触百分比（%BIC）、骨形成和骨重塑情况。
在植入后1周，未照射侧和照射侧种植体界面均开始形成编织骨。观察到表面A的平均%BIC（总骨/皮质骨/松质骨床）为26%/49%/36%，表面B为46%/48%/64%，表面C为81%/83%/78%。在照射后的半侧下颌骨中，表面A的平均%BIC（总骨/皮质骨/松质骨床）降至为11%/9%/4%，表面B为43%/46%/43%，表面C为63%/85%/76%，照射后种植体周围骨吸收增加，骨形成延迟。
所有照射后种植体的总%BIC均有所降低，虽然无统计学意义，但在松质骨床中，表面A和B的降低具有显著性（P≤0.05）。
与表面C处已进展的骨形成和成熟相比，松质骨床中表面A和B处骨形成延迟表明在开始照射时是对辐射更敏感的情况。
