Pereira Jorge, Morsch Carolina S, Henriques Bruno, Nascimento Rubens M, Benfatti Cesar Am, Silva Filipe S, López-López José, Souza Júlio Cm
Int J Oral Maxillofac Implants. 2016 Jul-Aug;31(4):813-9. doi: 10.11607/jomi.4173.
The aim of this study was to evaluate the removal torque and in vitro biofilm penetration at Morse taper and hexagonal implant-abutment joints after fatigue tests.
Sixty dental implants were divided into two groups: (1) Morse taper and (2) external hexagon implant-abutment systems. Fatigue tests on the implant-abutment assemblies were performed at a normal force (FN) of 50 N at 1.2 Hz for 500,000 cycles in growth medium containing human saliva for 72 hours. Removal torque mean values (n = 10) were measured after fatigue tests. Abutments were then immersed in 1% protease solution in order to detach the biofilms for optical density and colony-forming unit (CFU/cm²) analyses. Groups of implant-abutment assemblies (n = 8) were cross-sectioned at 90 degrees relative to the plane of the implant-abutment joints for the microgap measurement by field-emission guns scanning electron microscopy.
Mean values of removal torque on abutments were significantly lower for both Morse taper (22.1 ± 0.5 μm) and external hexagon (21.1 ± 0.7 μm) abutments after fatigue tests than those recorded without fatigue tests (respectively, 24 ± 0.5 μm and 24.8 ± 0.6 μm) in biofilm medium for 72 hours (P = .04). Mean values of microgap size for the Morse taper joints were statistically signicantly lower without fatigue tests (1.7 ± 0.4 μm) than those recorded after fatigue tests (3.2 ± 0.8 μm). Also, mean values of microgap size for external hexagon joints free of fatigue were statistically signicantly lower (1.5 ± 0.4 μm) than those recorded after fatigue tests (8.1 ± 1.7 μm) (P < .05). The optical density of biofilms and CFU mean values were lower on Morse taper abutments (Abs630nm at 0.06 and 2.9 × 10⁴ CFU/cm²) than that on external hexagon abutments (Abs630nm at 0.08 and 4.5 × 10⁴ CFU/cm²) (P = .01).
The mean values of removal torque, microgap size, and biofilm density recorded at Morse taper joints were lower in comparison to those recorded at external hexagon implant-abutment joints after fatigue tests in a simulated oral environment for 72 hours.
本研究的目的是评估在疲劳测试后，莫氏锥度和六角形种植体-基台连接处的拆卸扭矩和体外生物膜渗透情况。
60颗牙种植体分为两组：（1）莫氏锥度和（2）外六角种植体-基台系统。在含有人类唾液的生长培养基中，以50 N的法向力（FN）、1.2 Hz的频率对种植体-基台组件进行500,000次循环的疲劳测试，持续72小时。在疲劳测试后测量拆卸扭矩平均值（n = 10）。然后将基台浸入1%的蛋白酶溶液中，以分离生物膜，进行光密度和菌落形成单位（CFU/cm²）分析。将种植体-基台组件组（n = 8）相对于种植体-基台连接处平面以90度进行横截面切割，通过场发射枪扫描电子显微镜测量微间隙。
在生物膜培养基中培养72小时后，疲劳测试后莫氏锥度基台（22.1±0.5μm）和外六角基台（21.1±0.7μm）的基台拆卸扭矩平均值均显著低于未进行疲劳测试时记录的值（分别为24±0.5μm和24.8±0.6μm）（P = 0.04）。莫氏锥度连接处的微间隙尺寸平均值在未进行疲劳测试时（1.7±0.4μm）统计学上显著低于疲劳测试后记录的值（3.2±0.8μm）。同样，未进行疲劳测试的外六角连接处的微间隙尺寸平均值在统计学上也显著低于疲劳测试后记录的值（1.5±0.4μm）（8.1±1.7μm）（P < .05）。莫氏锥度基台上生物膜的光密度和CFU平均值（630nm处吸光度为0.06，2.9×10⁴ CFU/cm²）低于外六角基台（630nm处吸光度为0.08，4.5×10⁴ CFU/cm²）（P = 0.01）。
在模拟口腔环境中进行72小时疲劳测试后，莫氏锥度连接处记录的拆卸扭矩平均值、微间隙尺寸和生物膜密度均低于外六角种植体-基台连接处记录的值。
