Stavropoulos A, Cochran D, Obrecht M, Pippenger B E, Dard M
Department of Periodontology, Faculty of Odontology, Malmö University, Malmö, Sweden.
University of Texas Health Sciences Center, Department of Periodontics, San Antonio, Texas, USA.
Adv Dent Res. 2016 Mar;28(1):34-41. doi: 10.1177/0022034515624446.
The aim of the present preclinical in vivo study was to evaluate whether a modified "drill-only" protocol, involving slight underpreparation of the implant site, may have an effect on aspects of osseointegration of a novel bone-level tapered implant, compared with the "standard drilling" protocol involving taping and profiling of the marginal aspect of the implant socket. In each side of the edentulated and completely healed mandible of 11 minipigs, 2 tapered implants (8 mm long × 4.1 mm Ø, BLT; Institut Straumann AG, Basel, Switzerland) were installed either with the drill-only or the standard drilling protocol. Significantly lower average insertion torque values were recorded for the standard drilling protocol group (52 ± 29 Ncm) compared with the drill-only group (70 ± 27 Ncm) (t test, P ≤ 0.05); no significant difference was observed between the 2 groups regarding implant stability, by means of resonance frequency analysis (75 ± 8 vs. 75 ± 6, respectively). Half of the implants were immediately loaded and the rest were submerged, providing observation times of 8 or 4 wk, respectively. Non-decalcified histological and histomorphometric analysis of the implants with surrounding tissues showed no significant differences between the 2 drilling protocols regarding the distance from the implant platform to the first coronal bone-to-implant contact (f-BIC), the total bone-to-implant contact (BIC) as a percentage of the total implant perimeter, and the bone density in an area extending 1 mm laterally from the implant (BATA) within 2 rectangular regions of interest (ROIs) 4 mm in height, representing the coronal (parallel-walled) and apical (tapered) aspect of the implant (ROI 1 and ROI 2, respectively) in non-submerged implants. In general, marginal peri-implant bone levels were at or slightly apical to the implant platform, and large amounts of bone-to-implant contact were observed. In contrast, immediately loaded implants placed with the drill-only protocol showed statistically significantly lower BIC values (66% ± 13.7%) compared with those installed with the standard drilling protocol (74.8% ± 11.2%) (P = 0.018). In addition, although marginal bone levels were in most of the immediately loaded implants at or slightly apical to the implant platform, some of the implants installed with the drill-only protocol showed marginal bone loss and crater formation. Thus, in this model system, even slight underpreparation of the implant socket appeared to compromise osseointegration of immediately loaded bone-level tapered implants.
本临床前体内研究的目的是评估一种改良的“仅钻孔”方案（即种植体植入部位准备略有不足）与涉及对种植体窝边缘进行攻丝和成型的“标准钻孔”方案相比，是否会对新型骨水平锥形种植体的骨结合方面产生影响。在11只小型猪已无牙且完全愈合的下颌骨两侧，分别采用仅钻孔方案或标准钻孔方案植入2枚锥形种植体（8毫米长×4.1毫米直径，BLT；瑞士巴塞尔的士卓曼集团）。与仅钻孔组（70±27牛厘米）相比，标准钻孔方案组记录到的平均植入扭矩值显著更低（52±29牛厘米）（t检验，P≤0.05）；通过共振频率分析，两组在种植体稳定性方面未观察到显著差异（分别为75±8和75±6）。一半的种植体立即加载，其余的则进行埋植，分别观察8周或4周。对种植体及其周围组织进行未脱钙组织学和组织形态计量学分析，结果显示，在两个钻孔方案之间，对于未埋植种植体，在代表种植体冠部（平行壁）和根尖部（锥形）的两个高度为4毫米的矩形感兴趣区域（ROI 1和ROI 2）内，从种植体平台到首次冠状骨与种植体接触点（f-BIC）的距离、骨与种植体总接触面积（BIC）占种植体总周长的百分比以及从种植体横向延伸1毫米区域内的骨密度（BATA）方面均无显著差异。总体而言，种植体周围边缘骨水平位于种植体平台处或略低于种植体平台，且观察到大量骨与种植体的接触。相比之下，采用仅钻孔方案立即加载的种植体与采用标准钻孔方案植入的种植体相比，其BIC值在统计学上显著更低（66%±13.7%）（P = 0.018）。此外，尽管在大多数立即加载的种植体中，边缘骨水平位于种植体平台处或略低于种植体平台，但一些采用仅钻孔方案植入的种植体出现了边缘骨丢失和牙槽嵴顶凹陷形成。因此，在该模型系统中，即使种植体窝准备略有不足似乎也会损害立即加载的骨水平锥形种植体骨结合。
