Department of Prosthodontics, Propaeduetics and Dental Materials, School of Dentistry, Christian-Albrechts-University at Kiel, Germany.
Int J Oral Maxillofac Implants. 2011 Sep-Oct;26(5):941-6.
The vertical location of the implant-abutment connection influences the subsequent reaction of the peri-implant bone. It is not known, however, whether any additional influence is exerted by different microgap configurations. Therefore, the radiographic bone reactions of two different implant systems were monitored for 6 months.
In eight mongrel dogs, two implants with an internal Morse-taper connection (INT group) were placed on one side of the mandible; the contralateral side received two implants with an external-hex connection (EXT group). On each side, one implant was aligned at the bone level (equicrestal) and the second implant was placed 1.5 mm subcrestal. Healing abutments were placed 3 months after submerged healing, and the implants were maintained for another 3 months without prosthetic loading. At implant placement and after 1, 2, 3, 4, 5, and 6 months, standardized radiographs were obtained, and peri-implant bone levels were measured with regard to microgap location and evaluated statistically.
All implants osseointegrated clinically and radiographically. The overall mean bone loss was 0.68 ± 0.59 mm in the equicrestal INT group, 1.32 ± 0.49 mm in the equicrestal EXT group, 0.76 ± 0.49 mm in the subcrestal INT group, and 1.88 ± 0.81 mm in the subcrestal EXT group. The differences between the INT and EXT groups were statistically significant (paired t tests). The first significant differences between the internal and external groups were seen at month 1 in the subcrestal groups and at 3 months in the equicrestal groups. Bone loss was most pronounced in the subcrestal EXT group.
Within the limits of this study, different microgap configurations can cause different amounts of bone loss, even before prosthetic loading. Subcrestal placement of a butt-joint microgap design may lead to more pronounced radiographic bone loss.
种植体-基台连接的垂直位置会影响种植体周围骨的后续反应。然而，目前尚不清楚不同微间隙构型是否会产生任何额外的影响。因此，本研究监测了两种不同种植系统的 6 个月影像学骨反应。
在 8 只杂种犬中，一侧下颌骨植入 2 枚具有内部莫氏锥度连接的种植体（INT 组），对侧下颌骨植入 2 枚具有外部六方连接的种植体（EXT 组）。每侧的 1 枚种植体与骨嵴平齐（平齐组），第 2 枚种植体位于骨下 1.5mm（骨下组）。愈合基台于愈合期结束后 3 个月放置，种植体在无负载状态下维持 3 个月。在种植体植入时以及植入后 1、2、3、4、5 和 6 个月时，获得标准化 X 线片，并测量微间隙位置的种植体周围骨水平，并进行统计学评估。
所有种植体均临床和影像学成功骨整合。平齐 INT 组的总体平均骨吸收量为 0.68±0.59mm，平齐 EXT 组为 1.32±0.49mm，骨下 INT 组为 0.76±0.49mm，骨下 EXT 组为 1.88±0.81mm。INT 组和 EXT 组之间的差异具有统计学意义（配对 t 检验）。在骨下组中，第 1 个月时即可观察到内部组和外部组之间的首次显著差异，而在平齐组中，第 3 个月时则可观察到这种差异。骨下 EXT 组的骨吸收最为显著。
在本研究范围内，即使在未负载修复体之前，不同的微间隙构型也可能导致不同程度的骨吸收。平齐位置的骨下对接微间隙设计可能导致更明显的影像学骨吸收。
