METHODS: A balanced, randomized, double-blind clinical trial with two parallel experimental arms was conducted without a control group. The arms were \"cylindrical\" abutment and \"concave\" abutment. Eighty hexagonal internal connection implants, each with a diameter of 4 × 10 mm, were placed in healed mature bone. The main variable was the peri-implant tissue stability, which was measured as MBL at 8 weeks and 6 months.
RESULTS: The final sample consisted of 77 implants that were placed in 25 patients. 38 (49.4%) were placed using the cylindrical abutment, and the other 39 (50.6%) were placed using the concave abutment. The early global MBL of -0.6 ± 0.7 mm in the cylindrical abutment group was significantly higher than it was in the concave abutment group, in which the early global MBL was -0.4 ± 0.6 mm (p = .030). The estimated effect size (ES) was negative for the cylindrical abutment (ES = -1.3730, CI -2.5919 to -0.1327; t-value = -2.4893; p = .0139), therefore implying a loss of mean bone level, and it was positive for the concave abutment (ES = 2.8231; CI: 1.4379 to 4.2083; t-value = 4.0957; p = .0002), therefore implying an increase in the average bone level.
CONCLUSIONS: The concave abutments presented significantly less early MBL at 6 months post-loading than classical cylindrical abutments did.
方法:平衡,随机化,在没有对照组的情况下,采用两个平行实验组进行双盲临床试验.臂为“圆柱形”基台和“凹形”基台。八十个内六角连接植入物,每个直径为4×10毫米,被放置在愈合的成熟骨中。主要变量是种植体周围组织的稳定性,在8周和6个月时测量为MBL。
结果:最终样品由放置在25名患者中的77个植入物组成。38(49.4%)使用圆柱形基台放置,和其他39(50.6%)使用凹基台放置。圆柱形基牙组的早期整体MBL为-0.6±0.7mm,明显高于凹形基牙组,其中早期全球MBL为-0.4±0.6mm(p=.030)。圆柱形基台的估计效应大小(ES)为负(ES=-1.3730,CI-2.5919至-0.1327;t值=-2.4893;p=.0139),因此意味着平均骨骼水平的损失,并且对凹基台为正(ES=2.8231;CI:1.4379至4.2083;t值=4.0957;p=.0002),因此意味着平均骨骼水平的增加。
结论:在加载后6个月,凹面基台的早期MBL明显少于经典的圆柱形基台。