School of Medicine, Ewha Womans University, Seoul, South Korea.
Department of Oral and Maxillofacial Surgery, School of Medicine, Ewha Womans University, Anyangcheon-ro 1071, Yangcheon-gu, Seoul, 158-710, South Korea.
BMC Oral Health. 2020 Nov 10;20(1):315. doi: 10.1186/s12903-020-01310-4.
Osseointegrated implants are considered as clinically non-movable. Parathyroid hormone (PTH) is known to play a significant role in the regulation of bone remodeling and in intermittent, low doses, result in osteoanabolic effects. This study aimed to investigate the effects of PTH and corticotomy, both under traction force, on osseointegrated implants.
Four implants-two in each hemimandible-were placed in each of the three study mongrels. Each mongrels were designated as control, normal dose PTH (PTH-1), and high dose PTH (PTH-2) groups, with each groups further subdivided into non-surgery implant and surgery implant. After osseointegration, mechanical force with NiTi closed coil springs (500 g) was applied around each implants. Corticotomy was performed around one of four implants in each mongrels. Parathyroid hormone was administered locally on a weekly basis for 20 weeks. Clinical movement of the implants were evaluated with the superimposed 3D- scanned data, bone- microarchitectural and histologic examinations.
Superimposition analysis showed continuous movement of the non-surgery implant of PTH-1 group. Movement was further justified with lowest bone implant contact (adjusted BIC; 44.77%) in histomorphometric analysis. Upregulation of bone remodeling around the implant was observed in the normal dose PTH group. In the surgery implants, the remarkably higher adjusted BIC compared to the non-surgery implants indicated increased bone formation around the implant surface.
The results indicate that the catabolic and anabolic balance of osseointegrated implants in terms of bone remodeling can be shifted via various interventions including pharmacological, surgical and mechanical force.
Upregulated bone remodeling by PTH and corticotomy under continuous mechanical force showed the possible implications for the movement of osseointegrated dental implant.
骨整合种植体被认为在临床上是不可移动的。甲状旁腺激素（PTH）在调节骨重塑方面起着重要作用，并且在间歇性、低剂量的情况下，会产生成骨作用。本研究旨在探讨 PTH 和皮质切开术在牵引力作用下对骨整合种植体的影响。
在三只实验杂种犬的每只半下颌骨中各放置两颗种植体。每只杂种犬分别被指定为对照组、正常剂量 PTH（PTH-1）组和高剂量 PTH（PTH-2）组，每组再分为非手术种植体组和手术种植体组。在骨整合后，用镍钛闭合线圈弹簧（500g）围绕每个种植体施加机械力。在每只杂种犬的四颗种植体中的一颗周围进行皮质切开术。每周局部给予甲状旁腺激素治疗 20 周。通过重叠的 3D 扫描数据、骨微结构和组织学检查评估种植体的临床移动情况。
叠加分析显示 PTH-1 组的非手术种植体持续移动。组织形态计量学分析显示，最低的骨-种植体接触率（调整后的 BIC；44.77%）进一步证明了这种移动。正常剂量 PTH 组观察到种植体周围骨重塑的上调。在手术种植体中，与非手术种植体相比，显著更高的调整后的 BIC 表明种植体表面周围有更多的骨形成。
结果表明，通过各种干预措施，包括药理学、手术和机械力，可以改变骨整合种植体在骨重塑方面的分解代谢和合成代谢平衡。
PTH 和皮质切开术在持续机械力作用下增强的骨重塑表明，这可能对骨整合牙科种植体的移动产生影响。
